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Text File  |  1990-03-09  |  59KB  |  2,018 lines
  1. .RR--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!--!
  2. .PL 62
  3. .LM 1
  4. .RM 78
  5. .MT3
  6. .MB4
  7. .HM1
  8. .FM1
  9. .PO10
  10. .CW10
  11. .SR2
  12. .UJ0
  13. .OJ0
  14. .UL1
  15. .hePhysical Characteristics                                                3/9/90
  16. .foSCSI-2 draft proposed American National Standard        4-#      Revision 10c
  17. .pn 1
  18. .cp 30
  19. .aw off
  20. .pm 0
  21. 4. Physica∞ Characteristics
  22. .aw on
  23. .pm 3
  24.  
  25. ááThi≤ sectioε contain≤ thσ physica∞ definitioε oµ SCS╔-2«  Thσ connectors¼ ì
  26. cables¼ signals¼ terminators¼ anΣ bu≤ timinτ value≤ needeΣ t∩ implemen⌠ thσ ì
  27. interfacσ arσ covered.
  28.  
  29. .cp 20
  30. .aw off
  31. .pm 0
  32. 4.1. Physica∞ Description
  33. .aw on
  34. .pm 3
  35.  
  36. ááSCS╔ device≤ arσ dais∙-chaineΣ togethe≥ usinτ ß commoε 5░-conducto≥ Acablσ ì
  37. and¼ optionally¼ ß 6╕-conducto≥ ┬ cable«  BotΦ end≤ oµ eacΦ cablσ arσ ì
  38. terminated«  Al∞ signal≤ arσ commoε betweeε al∞ SCS╔ device≤ oε thσ Acable«  ì
  39. Iε system≤ tha⌠ emplo∙ thσ widσ SCS╔ option¼ widσ SCS╔ device≤ additionall∙ ì
  40. connec⌠ t∩ thσ Bcable«  Variou≤ widtΦ SCS╔ device≤ ma∙ bσ mixed.
  41.  
  42. .lm 3
  43. ááIMPLEMENTOR╙ NOTE║  X3T9.▓ i≤ documentinτ aε alternatσ 1╢-bi⌠ singlσ-cablσ ì
  44. áásolutioε anΣ aε alternatσ 3▓-bi⌠ solutioε anΣ expect≤ t∩ bσ ablσ t∩ removσ ì
  45. ááthσ ┬ cablσ definitioε iε ß futurσ versioε oµ SCSI.
  46. .lm 1
  47.  
  48. ááTw∩ driver/receive≥ alternative≤ arσ specified:
  49. áá(1⌐ Singlσ-endeΣ driver≤ anΣ receivers¼ whicΦ allo≈ ß maximuφ cablσ lengtΦ ì
  50. oµ si° meter≤ (primaril∙ fo≥ connectioε withiε ß cabinet).
  51. áá(2⌐ Differentia∞ driver≤ anΣ receivers¼ whicΦ allo≈ ß maximuφ cablσ lengtΦ ì
  52. oµ 2╡ meter≤ (primaril∙ fo≥ connectioε outsidσ oµ ß cabinet).
  53.  
  54. ááThσ singlσ-endeΣ anΣ differentia∞ alternative≤ arσ mutuall∙ exclusivσ withiε ì
  55. ß system.
  56.  
  57. .lm 3
  58. ááIMPLEMENTOR╙ NOTE║  Usσ oµ singlσ-endeΣ driver≤ anΣ receiver≤ witΦ thσ fas⌠ ì
  59. áásynchronou≤ datß transfe≥ optioε i≤ no⌠ recommended.
  60. .lm 1
  61.  
  62. .cp 20
  63. .aw off
  64. .pm 0
  65. 4.2. Cablσ Requirement≤  
  66. .aw on
  67. .pm 3
  68.  
  69. ááThσ characteristiπ impedancσ oµ thσ cablσ shoulΣ bσ n∩ les≤ thaε 9░ ohm≤ anΣ ì
  70. n∩ greate≥ thaε 14░ ohms«  Thσ characteristiπ impedancσ oµ thσ cablσ useΣ wheε ì
  71. implementinτ thσ fas⌠ synchronou≤ datß transfe≥ optioε i≤ defineΣ iε 4.2.3.
  72.  
  73. .pm 0
  74. .lm 3
  75. ááNOTE║  Therσ arσ successfu∞ singlσ-endeΣ implementation≤ usinτ cable≤ witΦ ì
  76. ááwitΦ les≤ thaε 9░ ohm≤ characteristiπ impedance«  Howeve≥, systeφ integrit∙ ì
  77. ááiε singlσ-endeΣ implementation≤ i≤ improveΣ wheε thσ characteristiπ ì
  78. ááimpedancσ oµ thσ cablσ i≤ greate≥ thaε 9░ ohms«  Cablσ parameter≤ othe≥ thaε ì
  79. áácharacteristiπ impedancσ arσ critica∞ t∩ systeφ integrity«  Thσ X3T9.▓ Tasδ ì
  80. ááGrou≡ i≤ investigatinτ alternativσ way≤ t∩ specif∙ cablσ parameter≤ a≤ ß ì
  81. áápar⌠ oµ ß futurσ versioε oµ SCSI.
  82. .lm 1
  83.  
  84. áá┴ minimuφ conducto≥ sizσ oµ 0.0804▓ squarσ mφ (2╕ AWG⌐ shoulΣ bσ useΣ t∩ ì
  85. minimizσ noisσ effect≤ anΣ ensurσ prope≥ distributioε oµ terminato≥ power«  ì
  86. ┴ smalle≥ conducto≥ sizσ ma∙ bσ useΣ fo≥ signal≤ othe≥ thaε terφinato≥ power. 
  87.  
  88. .pm 0
  89. .lm 3
  90. ááIMPLEMENTOR╙ NOTES:
  91. áá(1⌐ T∩ minimizσ discontinuitie≤ anΣ signa∞ reflections¼ cable≤ oµ differen⌠ ì
  92. ááimpedance≤ shoulΣ no⌠ bσ useΣ iε thσ samσ bus«  Implementation≤ ma∙ requirσ ì
  93. áátradσ-off≤ iε shieldinτ effectiveness¼ cablσ length¼ thσ numbe≥ oµ loads¼ ì
  94. áátransfe≥ rates¼ anΣ cos⌠ t∩ achievσ satisfactor∙ systeφ operation« 
  95. áá(2⌐ T∩ minimizσ discontinuitie≤ duσ t∩ loca∞ impedancσ variation¼ ß fla⌠ ì
  96. áácablσ shoulΣ bσ spaceΣ a⌠ leas⌠ 1.2╖ mφ (0.05░ in⌐ froφ othe≥ cables¼ an∙ ìèááothe≥ conductor¼ o≥ thσ cablσ itselµ wheε thσ cablσ i≤ folded.
  97. áá(3⌐ Regulator∙ agencie≤ ma∙ requirσ usσ oµ large≥ wirσ size«  
  98. .lm 1
  99. .pm 0
  100.  
  101. .cp 10
  102. .aw off
  103. .pm 0
  104. 4.2.1. Singlσ-EndeΣ Cable
  105. .aw on
  106. .pm 3
  107.  
  108. áá┴ 5░-conducto≥ fla⌠ cablσ o≥ 2╡-signa∞ twisteΣ-pai≥ cablσ shal∞ bσ useΣ fo≥ ì
  109. thσ ┴ cable«  ┴ 6╕-conducto≥ fla⌠ cablσ o≥ 3┤-signa∞ twisteΣ-pai≥ cablσ shal∞ ì
  110. bσ useΣ fo≥ thσ ┬ cablσ iµ thσ widσ SCS╔ optioε i≤ implemented«  Thσ maximuφ ì
  111. cumulativσ cablσ lengtΦ shal∞ bσ 6.░ meters«  Iµ twisteΣ-pai≥ cable≤ arσ used¼ ì
  112. theε twisteΣ pair≤ iε thσ cablσ shal∞ bσ wireΣ t∩ physicall∙ opposinτ contact≤ ì
  113. iε thσ connector.
  114.  
  115. .cp 5
  116. áá┴ stuΓ lengtΦ oµ n∩ morσ thaε 0.▒ meter≤ i≤ alloweΣ ofµ thσ mainlinσ ì
  117. interconnectioε withiε an∙ connecteΣ equipmen⌠ o≥ froφ an∙ connecteΣ point.
  118.  
  119. .lm 3
  120. ááIMPLEMENTOR╙ NOTE║  StuΓ clusterinτ shoulΣ bσ avoided«  Stub≤ shoulΣ bσ ì
  121. ááspaceΣ a⌠ leas⌠ 0.│ meter≤ apart.
  122. .lm 1
  123.  
  124. .cp 5
  125. ááSCS╔ bu≤ terminatioε shal∞ bσ a⌠ eacΦ enΣ oµ thσ cablσ anΣ ma∙ bσ interna∞ ì
  126. t∩ thσ SCS╔ device≤ tha⌠ arσ a⌠ thσ end≤ oµ thσ cable.
  127.  
  128. .cp 10
  129. .aw off
  130. .pm 0
  131. 4.2.2. Differentia∞ Cable
  132. .aw on
  133. .pm 3
  134.  
  135. áá┴ 5░-conducto≥ fla⌠ cablσ o≥ 2╡-signa∞ twisteΣ-pai≥ cablσ shal∞ bσ useΣ fo≥ ì
  136. thσ Acable«  ┴ 6╕-conducto≥ fla⌠ cablσ o≥ 3┤-signa∞ twisteΣ-pai≥ cablσ shal∞ ì
  137. bσ useΣ fo≥ thσ Bcablσ iµ thσ widσ SCS╔ optioε i≤ implemented«  Thσ maximuφ ì
  138. cumulativσ cablσ lengtΦ shal∞ bσ 2╡ meters«  Iµ twisteΣ-pai≥ cable≤ arσ used¼ ì
  139. theε twisteΣ pair≤ iε thσ cablσ shal∞ bσ wireΣ t∩ physicall∙ opposinτ contact≤ ì
  140. iε thσ connector.
  141.  
  142. áá┴ stuΓ lengtΦ oµ n∩ morσ thaε 0.▓ meter≤ i≤ alloweΣ ofµ thσ mainlinσ ì
  143. interconnectioε withiε an∙ connecteΣ equipmen⌠ o≥ froφ an∙ connecteΣ point.
  144.  
  145. ááSCS╔ bu≤ terminatioε shal∞ bσ a⌠ eacΦ enΣ oµ thσ cablσ anΣ ma∙ bσ interna∞ ì
  146. t∩ thσ SCS╔ device≤ tha⌠ arσ a⌠ thσ end≤ oµ thσ cable.
  147.  
  148. .pm 0
  149. .lm 3
  150. ááIMPLEMENTOR╙ NOTE║  Thσ usσ oµ twisteΣ pai≥ cablσ (eithe≥ twisteΣ-fla⌠ o≥ ì
  151. áádiscretσ wirσ twisteΣ pairs⌐ i≤ strongl∙ recommended«  Withou⌠ twisteΣ ì
  152. áápairs¼ eveε a⌠ slo≈ datß rate≤ anΣ ver∙ shor⌠ distances¼ crosstalδ betweeε ì
  153. ááadjacen⌠ signal≤ cause≤ spuriou≤ pulse≤ witΦ differentia∞ signals.
  154. .pm 3
  155. .lm 1
  156.  
  157. .cp 5
  158. .aw off
  159. .pm 0
  160. 4.2.3. Cablσ Requirement≤ fo≥ Fas⌠ Synchronou≤ Datß Transfer
  161. .aw on
  162. .pm 3
  163.  
  164. ááIε system≤ whicΦ usσ thσ fas⌠ synchronou≤ datß transfe≥ optioε (seσ 4.8)¼ ì
  165. thσ AanΣ Bcable≤ shoulΣ mee⌠ thσ conducto≥ sizσ recommendatioε iε 4.2«  Thσ ì
  166. cablσ shoulΣ havσ aε overal∞ shielΣ suitablσ fo≥ terminatioε iε ß shieldeΣ ì
  167. connector.
  168.  
  169. .cp 11èááIε sucΦ systems¼ thσ cable≤ shal∞ havσ thσ followinτ electrica∞ ì
  170. characteristics:
  171. .pm 6
  172. áááááCharacteristiπ Impedance║  9░ t∩ 13▓ ohms
  173. áááááSigna∞ Attenuation║  0.09╡ d┬ maximuφ pe≥ mete≥ a⌠ ╡ MHz
  174. áááááPai≥-t∩-Pai≥ Propagatioε Dela∙ Delta║  0.2░ n≤ maximuφ pe≥ meter
  175. áááááD├ Resistance║  0.23░ ohm≤ maximuφ pe≥ mete≥ a⌠ 2░ degree≤ C
  176. .pm3
  177.  
  178.  
  179. .cp 20
  180. .aw off
  181. .pm 0
  182. 4.3. Connecto≥ Requirements
  183. .aw on
  184. .pm 3
  185.  
  186. ááTw∩ type≤ oµ connector≤ arσ defined║ nonshieldeΣ anΣ shielded«  Thσ ì
  187. nonshieldeΣ connector≤ arσ typicall∙ useΣ fo≥ iε-cabine⌠ applications«  ì
  188. ShieldeΣ connector≤ arσ typicall∙ useΣ fo≥ externa∞ application≤ wherσ ì
  189. electromagnetiπ compatibilit∙ (EMC⌐ anΣ electrostatiπ dischargσ (ESD⌐ ì
  190. protectioε ma∙ bσ required«  Eithe≥ typσ oµ connecto≥ ma∙ bσ useΣ witΦ thσ ì
  191. singlσ-endeΣ o≥ differentia∞ drivers.
  192.  
  193. .cp 10
  194. .aw off
  195. .pm 0
  196. 4.3.1. NonshieldeΣ Connecto≥ Requirements
  197. .aw on
  198. .pm 3
  199.  
  200. ááTw∩ nonshieldeΣ connecto≥ alternative≤ arσ specifieΣ fo≥ thσ ┴ cablσ anΣ onσ ì
  201. nonshieldeΣ connecto≥ i≤ specifieΣ fo≥ thσ ┬ cable.
  202.  
  203. .cp 10
  204. .aw off
  205. .pm 0
  206. 4.3.1.1. Nonshielded Connecto≥ Alternativσ ▒ ¡ ┴ Cable
  207. .aw on
  208. .pm 3
  209.  
  210. ááThσ alternativσ ▒ nonshieldeΣ higΦ-densit∙ SCS╔ devicσ connecto≥ fo≥ thσ ┴ ì
  211. cablσ (Figurσ ┤-1⌐ shal∞ bσ ß 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ ì
  212. 2╡ femalσ contact≤ witΦ adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ ì
  213. nonmatinτ portioε oµ thσ connecto≥ i≤ showε fo≥ referencσ only.
  214.  
  215. ááThσ alternativσ ▒ nonshieldeΣ higΦ-densit∙ cablσ connecto≥ fo≥ thσ ┴ cablσ ì
  216. (Figurσ ┤-2⌐ shal∞ bσ ß 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 2╡ ì
  217. malσ contact≤ witΦ adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ ì
  218. portioε oµ thσ connecto≥ i≤ showε fo≥ referencσ only.
  219.  
  220. .cp 10
  221. .aw off
  222. .pm 0
  223. 4.3.1.2. Nonshielded Connecto≥ Alternativσ 2 ¡ ┴ Cable
  224. .aw on
  225. .pm 3
  226.  
  227. ááThσ alternativσ ▓ nonshieldeΣ lo≈-densit∙ SCS╔ devicσ connecto≥ fo≥ thσ ┴ ì
  228. cablσ (Figurσ ┤-3⌐ shal∞ bσ ß 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ ì
  229. 2╡ malσ pin≤ witΦ adjacen⌠ pin≤ 2.5┤ mφ (0.▒ in⌐ apart«  ┴ shrouΣ anΣ heade≥ ì
  230. bod∙ shoulΣ bσ used«  Thσ nonmatinτ portioε oµ thσ connecto≥ i≤ showε fo≥ ì
  231. referencσ only.
  232.  
  233. ááThσ alternativσ ▓ nonshieldeΣ lo≈-densit∙ cablσ connecto≥ fo≥ thσ ┴ cablσ ì
  234. (Figurσ ┤-4⌐ shal∞ bσ ß 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 2╡ ì
  235. femalσ contact≤ witΦ adjacen⌠ contact≤ 2.5┤ mφ (0.▒ in⌐ apart«  I⌠ i≤ ì
  236. recommendeΣ tha⌠ keyeΣ connector≤ bσ used.
  237.  
  238. .cp 10è.aw off
  239. .pm 0
  240. 4.3.1.3. Nonshielded Connecto≥ ¡ B Cable
  241. .aw on
  242. .pm 3
  243.  
  244. ááThσ nonshieldeΣ higΦ-densit∙ SCS╔ devicσ connecto≥ fo≥ thσ ┬ cablσ (Figurσ ì
  245. ┤-1⌐ shal∞ bσ ß 6╕-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 3┤ femalσ ì
  246. contact≤ witΦ adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ ì
  247. portioε oµ thσ connecto≥ i≤ showε fo≥ referencσ only.
  248.  
  249. ááThσ nonshieldeΣ higΦ-densit∙ cablσ connecto≥ fo≥ thσ ┬ cablσ (Figurσ ┤-2⌐ ì
  250. shal∞ bσ ß 6╕-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 3┤ malσ contact≤ ì
  251. witΦ adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ ì
  252. connecto≥ i≤ showε fo≥ referencσ only.
  253.  
  254. .cp 10
  255. .aw off
  256. .pm 0
  257. 4.3.2. ShieldeΣ Connecto≥ Requirements
  258. .aw on
  259. .pm 3
  260.  
  261. ááTw∩ shieldeΣ connecto≥ alternative≤ arσ specifieΣ fo≥ thσ ┴ cablσ anΣ onσ ì
  262. shieldeΣ connecto≥ i≤ specifieΣ fo≥ thσ ┬ cable«  Thσ connecto≥ shieldinτ ì
  263. systeφ shoulΣ providσ ß dπ resistancσ oµ les≤ thaε 10millΘohm≤ froφ thσ ì
  264. cablσ shielΣ a⌠ it≤ terminatioε poin⌠ t∩ thσ SCS╔ devicσ enclosure.
  265.  
  266. ááIε orde≥ t∩ suppor⌠ dais∙-chaiε connections¼ SCS╔ device≤ tha⌠ usσ shieldeΣ ì
  267. connector≤ shoulΣ providσ tw∩ shieldeΣ devicσ connector≤ oε thσ devicσ ì
  268. enclosure«  Thesσ tw∩ connector≤ ma∙ bσ wireΣ "onσ-t∩-oneó witΦ ß stuΓ t∩ thσ ì
  269. SCS╔ device'≤ driver≤ anΣ receiver≤ provideΣ thσ maximuφ stuΓ lengtΦ i≤ no⌠ ì
  270. violated«  Alternatively¼ tw∩ cable≤ ma∙ bσ ruε froφ thσ tw∩ shieldeΣ ì
  271. connector≤ t∩ thσ driver≤ anΣ receiver≤ s∩ tha⌠ thσ maximuφ stuΓ lengtΦ i≤ no⌠ ì
  272. violated«  Thσ lengtΦ oµ thσ cablσ withiε thσ devicσ enclosurσ i≤ includeΣ ì
  273. wheε calculatinτ thσ tota∞ cablσ lengtΦ oµ thσ SCS╔ bus.
  274.  
  275. .lm3
  276. ááIMPLEMENTOR╙ NOTE║  SCS╔-▒ defineΣ threσ shieldeΣ connecto≥ system≤ iε aε ì
  277. ááappendix«  Thσ alternativσ ▒ shieldeΣ connecto≥ oµ SCS╔-▒ ha≤ beeε replaceΣ ì
  278. ááb∙ ß higΦ-densit∙ connecto≥ iε thi≤ standard«  Thσ alternativσ ▓ shieldeΣ ì
  279. ááconnecto≥ remain≤ unchanged«  Thσ EUROCAR─ Boxe≤ shieldeΣ connecto≥ systeφ ì
  280. ááoµ SCS╔-▒ ha≤ beeε deleteΣ iε thi≤ standard.
  281. .lm1
  282.  
  283. .cp 10
  284. .aw off
  285. .pm 0
  286. 4.3.2.1. ShieldeΣ Connecto≥ Alternativσ ▒ ¡ ┴ Cable
  287. .aw on
  288. .pm 3
  289.  
  290. ááThσ shieldeΣ higΦ-densit∙ SCS╔ devicσ connecto≥ fo≥ thσ ┴ cablσ (Figurσ ┤-5⌐ ì
  291. i≤ ß 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 2╡ femalσ contact≤ witΦ ì
  292. adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ ì
  293. connecto≥ i≤ showε fo≥ referencσ only.
  294.  
  295. ááThσ shieldeΣ higΦ-densit∙ cablσ connecto≥ fo≥ thσ ┴ cablσ (Figurσ ┤-6⌐ i≤ ß ì
  296. 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 2╡ malσ contact≤ witΦ ì
  297. adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ ì
  298. connecto≥ i≤ showε fo≥ referencσ only.
  299.  
  300. .cp 10è.aw off
  301. .pm 0
  302. 4.3.2.2. Shielded Connecto≥ Alternativσ 2 ¡ ┴ Cable
  303. .aw on
  304. .pm 3
  305.  
  306. ááThσ shieldeΣ lo≈-densit∙ devicσ connecto≥ fo≥ thσ ┴ cablσ (Figurσ ┤-7⌐ i≤ ß ì
  307. 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ ribboε contact≤ spaceΣ 2.1╢ ì
  308. mφ (0.08╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ connecto≥ i≤ showε fo≥ ì
  309. referencσ only.
  310.  
  311. ááThσ shieldeΣ lo≈-densit∙ cablσ connecto≥ fo≥ thσ ┴ cablσ (Figurσ ┤-8⌐ i≤ ß ì
  312. 5░-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ ribboε contact≤ spaceΣ 2.1╢ ì
  313. mφ (0.08╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ connecto≥ i≤ showε fo≥ ì
  314. referencσ only.
  315.  
  316. .cp 10
  317. .aw off
  318. .pm 0
  319. 4.3.2.3. Shielded Connecto≥ ¡ B Cable
  320. .aw on
  321. .pm 3
  322.  
  323. ááThσ shieldeΣ higΦ-densit∙ SCS╔ devicσ connecto≥ fo≥ thσ ┬ cablσ (Figurσ ┤-5⌐ ì
  324. i≤ ß 6╕-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 3┤ femalσ contact≤ witΦ ì
  325. adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ ì
  326. connecto≥ i≤ showε fo≥ referencσ only.
  327.  
  328. ááThσ shieldeΣ higΦ-densit∙ cablσ connecto≥ fo≥ thσ ┬ cablσ (Figurσ ┤-6⌐ i≤ ß ì
  329. 6╕-conducto≥ connecto≥ consistinτ oµ tw∩ row≤ oµ 3┤ malσ contact≤ witΦ ì
  330. adjacen⌠ contact≤ 1.2╖ mφ (0.0╡ in⌐ apart«  Thσ nonmatinτ portioε oµ thσ ì
  331. connecto≥ i≤ showε fo≥ referencσ only.
  332.  
  333. .aw off
  334. .pm 0
  335. .pa è.. Figure 4-1 is inserted on this page
  336.  
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  384.  
  385.  
  386.  
  387.  
  388.    Figure 4-1: 50/68-Contact Nonshielded HigΦ-Densit∙ SCSI Device Connector
  389.                               (A Cable/┬ Cable)
  390. .paè.. Figure 4-2 is inserted on this page
  391.  
  392.  
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  439.  
  440.  
  441.  
  442.  
  443.       Figure 4-2: 50/68-Contact Nonshielded HigΦ-Densit∙ Cable Connector
  444.                               (A Cable/┬ Cable)
  445. .paè.. Figure 4-3 is inserted on this page
  446.  
  447.  
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  493.  
  494.  
  495.  
  496.  
  497.  
  498.      Figure 4-3: 50-Contact NonshieldeΣ Low-Density SCSI Device Connecto≥
  499.                                   (A Cable)
  500. .paè.. Figure 4-4 is inserted on this page
  501.  
  502.  
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  546.  
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  548.  
  549.  
  550.  
  551.  
  552.  
  553.         Figure 4-4: 50-Contact Nonshielded Low-Densit∙ Cable Connector
  554.                                   (A Cable)
  555. .cp 54è.. Figure 4-5 is inserted on this page
  556.  
  557.  
  558.  
  559.  
  560.  
  561.  
  562.  
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  579.  
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  581.  
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  600.  
  601.  
  602.  
  603.  
  604.  
  605.  
  606.  
  607.  
  608.  
  609.     Figure 4-5: 50/6╕-Contact Shielded High-densit∙ SCSI Device Connector
  610.                               (┴ Cable/┬ Cable)è.cp 54
  611. .. Figure 4-6 is inserted on this page
  612.  
  613.  
  614.  
  615.  
  616.  
  617.  
  618.  
  619.  
  620.  
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  655.  
  656.  
  657.  
  658.  
  659.  
  660.  
  661.  
  662.  
  663.  
  664.  
  665.        Figure 4-6: 50/6╕-Contact Shielded High-densit∙ Cable Connector
  666.                               (┴ Cablσ/┬ Cable)è.cp 54
  667. .. Figure 4-7 is inserted on this page
  668.  
  669.  
  670.  
  671.  
  672.  
  673.  
  674.  
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  714.  
  715.  
  716.  
  717.  
  718.  
  719.  
  720.  
  721.       Figure 4-7: 50-Contac⌠ Shielded Low-Densit∙ SCSI Device Connector
  722. .cp 54è.. Figure 4-8 is inserted on this page
  723.  
  724.  
  725.  
  726.  
  727.  
  728.  
  729.  
  730.  
  731.  
  732.  
  733.  
  734.  
  735.  
  736.  
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  766.  
  767.  
  768.  
  769.  
  770.  
  771.  
  772.  
  773.  
  774.  
  775.  
  776.          Figure 4-8: 50-Contac⌠ Shielded Low-Density Cable Connector
  777. è.cp 10
  778. .aw off
  779. .pm 0
  780. 4.3.3. Connecto≥ Contact Assignments
  781. .aw on
  782. .pm 3
  783.  
  784. ááThσ connecto≥ contac⌠ assignment≤ arσ defineΣ iε Table≤ ┤-▒ througΦ ┤-5«  ì
  785. Tablσ ┤-▒ define≤ whicΦ oµ thσ othe≥ fou≥ table≤ t∩ usσ anΣ whicΦ se⌠ oµ ì
  786. contac⌠ assignment≤ t∩ use.
  787.  
  788. .cp 30
  789. .aw off
  790. .pm 0
  791.          Table 4-1: Cross-Reference t∩ Connecto≥ Contac⌠ Assignments
  792.  
  793. ==============================================================================
  794.                               Driver/                        Contac⌠
  795.                              Receive≥           Connector  Assignmen⌠  Contact
  796.     Connecto≥ Typσ             Typσ      Cable    Figurσ      Tablσ      Set
  797. ------------------------------------------------------------------------------
  798. Nonshielded Alternativσ 1  Single-EndeΣ    ┴    4-▒ ª 4-▓      4-2        2
  799. Nonshielded Alternativσ 1  Single-EndeΣ    B    4-▒ ª 4-▓      4-│
  800. Nonshielded Alternativσ 1  Differentia∞    A    4-▒ ª 4-▓      4-┤        2
  801. Nonshielded Alternativσ 1  Differentia∞    B    4-▒ ª 4-▓      4-╡
  802.  
  803. Nonshielded Alternativσ 2  Single-EndeΣ    ┴    4-│ ª 4-┤      4-▓        1
  804. Nonshielded Alternativσ 2  Differentia∞    A    4-│ ª 4-┤      4-┤        1
  805.  
  806. Shielded Alternativσ 1     Single-EndeΣ    A    4-╡ ª 4-╢      4-▓        2
  807. Shielded Alternativσ 1     Single-EndeΣ    B    4-╡ ª 4-╢      4-│
  808. Shielded Alternativσ 1     Differentia∞    A    4-╡ ª 4-╢      4-┤        2
  809. ShieldeΣ Alternativσ 1     Differentia∞    B    4-╡ ª 4-╢      4-╡
  810.  
  811. ShieldeΣ Alternativσ 2     Single-EndeΣ    ┴    4-╖ ª 4-╕      4-▓        2
  812. ShieldeΣ Alternativσ 2     Differentia∞    ┴    4-╖ ª 4-╕      4-┤        ▓
  813. ==============================================================================
  814. .aw on
  815.  
  816.  
  817. .cp 42è.aw off
  818. .pm 0
  819.             Table 4-2: Single-Ended Contact Assignment≤ ¡ A Cable
  820.  
  821. ==============================================================================
  822.                   Connecto≥         Cablσ        Connector
  823.       Signa∞    Contact Number    Conducto≥    Contact Number    Signal      
  824.        Namσ      Se⌠ 2  Se⌠ 1      Number       Se⌠ 1  Se⌠ 2      Name       
  825. ------------------------------------------------------------------------------
  826.       GROUND       1      ▒         ▒ |  ▓        ▓     2╢       -DB(0)        
  827.       GROUND       2      3         3 |  4        4     27       -DB(1)        
  828.       GROUND       3      5         5 |  6        6     28       -DB(2)      
  829.       GROUND       4      7         7 |  8        8     29       -DB(3)      
  830.       GROUND       5      9         9 | 10       10     30       -DB(4)      
  831.       GROUND       6     11        11 | 12       12     31       -DB(5)      
  832.       GROUND       7     13        13 | 14       14     32       -DB(6)      
  833.       GROUND       8     15        15 | 16       16     33       -DB(7)      
  834.       GROUND       9     17        17 | 18       18     34       -DB(P)      
  835.       GROUND      10     19        19 | 20       20     35       GROUND      
  836.       GROUND      11     21        21 | 22       22     36       GROUND      
  837.       RESERVED    12     23        23 | 24       24     37       RESERVED    
  838.        OPEN       13     25        25 | 26       26     38       TERMPWR     
  839.       RESERVED    14     27        27 | 28       28     39       RESERVED    
  840.       GROUND      15     29        29 | 30       30     40       GROUND      
  841.       GROUND      16     31        31 | 32       32     41       -ATN        
  842.       GROUND      17     33        33 | 34       34     42       GROUND      
  843.       GROUND      18     35        35 | 36       36     43       -BSY        
  844.       GROUND      19     37        37 | 38       38     44       -ACK        
  845.       GROUND      20     39        39 | 40       40     45       -RST        
  846.       GROUND      21     41        41 | 42       42     46       -MSG        
  847.       GROUND      22     43        43 | 44       44     47       -SEL        
  848.       GROUND      23     4╡        4╡ | 46       46     48       -C/D        
  849.       GROUND      24     47        47 | 48       48     49       -REQ        
  850.       GROUND      25     49        49 | 50       50     50       -I/O        
  851. ==============================================================================
  852. .aw on
  853.  
  854. NOTES:
  855. (1⌐  Thσ minu≤ sigε nex⌠ t∩ ß signa∞ indicate≤ activσ low.
  856. (2⌐  Thσ conducto≥ numbe≥ refer≤ t∩ thσ conducto≥ positioε wheε usinτ 0.05░-ì
  857. incΦ centerlinσ fla⌠ ribboε cablσ witΦ ß lo≈-densit∙ connecto≥ o≥ wheε usinτ ì
  858. 0.02╡-incΦ centerlinσ fla⌠ ribboε cablσ witΦ ß higΦ-densit∙ connector«  Othe≥ ì
  859. cablσ type≤ ma∙ bσ useΣ t∩ implemen⌠ equivalen⌠ contac⌠ assignments.
  860. (3⌐  Tw∩ set≤ oµ contac⌠ assignment≤ arσ shown«  Refe≥ t∩ Tablσ ┤-▒ t∩ ì
  861. determinσ whicΦ se⌠ oµ contact≤ applie≤ t∩ eacΦ connector.
  862. (4⌐  Seσ 4.4.┤ fo≥ ß definitioε oµ thσ RESERVE─ lines.
  863.  
  864.  
  865. .cp 50è.aw off
  866. .pm 0
  867.             Table 4-3: Single-EndeΣ Contact Assignment≤ ¡ B Cable
  868.  
  869. ==============================================================================
  870.                     Connecto≥       Cablσ        Connector
  871.       Signa∞         Contac⌠      Conducto≥       Contact        Signal      
  872.        Namσ           Number       Number          Number         Name       
  873. ------------------------------------------------------------------------------
  874.       GROUND            1           ▒ |  ▓          35           GROUND  
  875.       GROUND            2           3 |  4          36           -DB(8)    
  876.       GROUND            3           5 |  6          37           -DB(9)  
  877.       GROUND            4           7 |  8          38           -DB(10) 
  878.       GROUND            5           9 | 10          39           -DB(11) 
  879.       GROUND            6          11 | 12          40           -DB(12) 
  880.       GROUND            7          13 | 14          41           -DB(13) 
  881.       GROUND            8          15 | 16          42           -DB(14) 
  882.       GROUND            9          17 | 18          43           -DB(15) 
  883.       GROUND           10          19 | 20          44           -DB(P1) 
  884.       GROUND           11          21 | 22          45           -ACKB   
  885.       GROUND           12          23 | 24          46           GROUND  
  886.       GROUND           13          25 | 26          47           -REQB   
  887.       GROUND           14          27 | 28          48           -DB(16) 
  888.       GROUND           15          29 | 30          49           -DB(17) 
  889.       GROUND           16          31 | 32          50           -DB(18) 
  890.      TERMPWRB          17          33 | 34          51           TERMPWRB
  891.      TERMPWRB          18          35 | 36          52           TERMPWRB
  892.       GROUND           19          37 | 38          53           -DB(19) 
  893.       GROUND           20          39 | 40          54           -DB(20) 
  894.       GROUND           21          41 | 42          55           -DB(21) 
  895.       GROUND           22          43 | 44          56           -DB(22) 
  896.       GROUND           23          4╡ | 46          57           -DB(23) 
  897.       GROUND           24          47 | 48          58           -DB(P2) 
  898.       GROUND           25          49 | 50          59           -DB(24) 
  899.       GROUND           26          5▒ ⁿ 5▓          60           -DB(25) 
  900.       GROUND           27          5│ ⁿ 54          61           -DB(26) 
  901.       GROUND           28          5╡ ⁿ 56          62           -DB(27) 
  902.       GROUND           29          5╖ ⁿ 58          63           -DB(28) 
  903.       GROUND           30          5╣ ⁿ 60          64           -DB(29) 
  904.       GROUND           31          6▒ ⁿ 62          65           -DB(30) 
  905.       GROUND           32          6│ ⁿ 64          66           -DB(31) 
  906.       GROUND           33          6╡ ⁿ 66          67           -DB(P3) 
  907.       GROUND           34          6╖ ⁿ 68          68           GROUN─  
  908. ==============================================================================
  909. .aw on
  910.  
  911. NOTES:
  912.   (1⌐  Thσ minu≤ sigε nex⌠ t∩ ß signa∞ indicate≤ activσ low.
  913.   (2⌐  Thσ conducto≥ numbe≥ refer≤ t∩ thσ conducto≥ positioε wheε usinτ 0.02╡-ì
  914. incΦ centerlinσ fla⌠ ribboε cable«  Othe≥ cablσ type≤ ma∙ bσ useΣ t∩ implemen⌠ ì
  915. equivalen⌠ contac⌠ assignments.
  916.  
  917. .lm 3
  918. ááIMPLEMENTOR╙ NOTE║  X3T9.▓ i≤ documentinτ aε alternatσ 1╢-bi⌠ singlσ-cablσ ì
  919. áásolutioε anΣ aε alternatσ 3▓-bi⌠ solutioε anΣ expect≤ t∩ bσ ablσ t∩ removσ ì
  920. ááthσ ┬ cablσ definitioε iε ß futurσ versioε oµ SCSI.
  921. .lm 1
  922.  
  923. .cp 42è.aw off
  924. .pm 0
  925.             Table 4-4: Differential Contact Assignments ¡ ┴ Cable
  926.  
  927. ==============================================================================
  928.                   Connecto≥         Cablσ        Connector
  929.       Signa∞    Contact Number    Conducto≥    Contact Number    Signal      
  930.        Namσ      Se⌠ 2  Se⌠ 1      Number       Se⌠ 1  Se⌠ 2      Name       
  931. ------------------------------------------------------------------------------
  932.       GROUN─       1      ▒         ▒ |  ▓        ▓     2╢       GROUND 
  933.       +DB(0)       2      3         3 |  4        4     27       -DB(0)       
  934.       +DB(1)       3      5         5 |  6        6     28       -DB(1)     
  935.       +DB(2)       4      7         7 |  8        8     29       -DB(2)     
  936.       +DB(3)       5      9         9 | 10       10     30       -DB(3)     
  937.       +DB(4)       6     11        11 | 12       12     31       -DB(4)     
  938.       +DB(5)       7     13        13 | 14       14     32       -DB(5)     
  939.       +DB(6)       8     15        15 | 16       16     33       -DB(6)     
  940.       +DB(7)       9     17        17 | 18       18     34       -DB(7)     
  941.       +DB(P)      10     19        19 | 20       20     35       -DB(P)     
  942.       DIFFSENS    11     21        21 | 22       22     36       GROUND     
  943.       RESERVED    12     23        23 | 24       24     37       RESERVED   
  944.       TERMPWR     13     25        25 | 26       26     38       TERMPWR    
  945.       RESERVED    14     27        27 | 28       28     39       RESERVED   
  946.       +ATN        15     29        29 | 30       30     40       -ATN       
  947.       GROUND      16     31        31 | 32       32     41       GROUND     
  948.       +BSY        17     33        33 | 34       34     42       -BSY       
  949.       +ACK        18     35        35 | 36       36     43       -ACK       
  950.       +RST        19     37        37 | 38       38     44       -RST       
  951.       +MSG        20     39        39 | 40       40     45       -MSG       
  952.       +SEL        21     41        41 | 42       42     46       -SEL       
  953.       +C/D        22     43        43 | 44       44     47       -C/D       
  954.       +REQ        23     4╡        4╡ | 46       46     48       -REQ       
  955.       +I/O        24     47        47 | 48       48     49       -I/O       
  956.       GROUND      25     49        49 | 50       50     50       GROUN─     
  957. ==============================================================================
  958. .aw on
  959.  
  960. NOTES:
  961.   (1⌐  Thσ conducto≥ numbe≥ refer≤ t∩ thσ conducto≥ positioε wheε usinτ 0.05░-ì
  962. incΦ centerlinσ fla⌠ ribboε cablσ witΦ ß lo≈-densit∙ connecto≥ o≥ wheε usinτ ì
  963. 0.02╡-incΦ centerlinσ fla⌠ ribboε cablσ witΦ ß higΦ-densit∙ connector«  Othe≥ ì
  964. cablσ type≤ ma∙ bσ useΣ t∩ implemen⌠ equivalen⌠ contac⌠ assignments.
  965.   (2⌐  Tw∩ set≤ oµ contac⌠ assignment≤ arσ shown«  Refe≥ t∩ Tablσ ┤-▒ t∩ ì
  966. determinσ whicΦ se⌠ oµ contact≤ applie≤ t∩ eacΦ connector.
  967.   (3⌐  Seσ 4.4.┤ fo≥ ß definitioε oµ thσ RESERVE─ lines.
  968.  
  969.  
  970. .cp 50è.aw off
  971. .pm 0
  972.             Table 4-5: Differential Contact Assignments ¡ ┬ Cable
  973.  
  974. ==============================================================================
  975.                     Connecto≥       Cablσ        Connector
  976.       Signa∞         Contac⌠      Conducto≥       Contact        Signal      
  977.        Namσ           Number       Number          Number         Name       
  978. ------------------------------------------------------------------------------
  979.       GROUND            1           ▒ |  ▓          35           GROUND  
  980.       +DB(8)            2           3 |  4          36           -DB(8)    
  981.       +DB(9)            3           5 |  6          37           -DB(9)  
  982.       +DB(10)           4           7 |  8          38           -DB(10) 
  983.       +DB(11)           5           9 | 10          39           -DB(11) 
  984.       +DB(12)           6          11 | 12          40           -DB(12) 
  985.       +DB(13)           7          13 | 14          41           -DB(13) 
  986.       +DB(14)           8          15 | 16          42           -DB(14) 
  987.       +DB(15)           9          17 | 18          43           -DB(15) 
  988.       +DB(P1)          10          19 | 20          44           -DB(P1) 
  989.       +ACK┬            11          21 | 22          45           -ACKB   
  990.       GROUND           12          23 | 24          46           DIFFSENS
  991.       +REQB            13          25 | 26          47           -REQB   
  992.       +DB(16)          14          27 | 28          48           -DB(16) 
  993.       +DB(17)          15          29 | 30          49           -DB(17) 
  994.       +DB(18)          16          31 | 32          50           -DB(18) 
  995.       TERMPWRB         17          33 | 34          51           TERMPWRB
  996.       TERMPWRB         18          35 | 36          52           TERMPWRB
  997.       +DB(19)          19          37 | 38          53           -DB(19) 
  998.       +DB(20)          20          39 | 40          54           -DB(20) 
  999.       +DB(21)          21          41 | 42          55           -DB(21) 
  1000.       +DB(22)          22          43 | 44          56           -DB(22) 
  1001.       +DB(23)          23          4╡ | 46          57           -DB(23) 
  1002.       +DB(P2)          24          47 | 48          58           -DB(P2) 
  1003.       +DB(24)          25          49 | 50          59           -DB(24) 
  1004.       +DB(25)          26          5▒ ⁿ 5▓          60           -DB(25) 
  1005.       +DB(26)          27          5│ ⁿ 54          61           -DB(26) 
  1006.       +DB(27)          28          5╡ ⁿ 56          62           -DB(27) 
  1007.       +DB(28)          29          5╖ ⁿ 58          63           -DB(28) 
  1008.       +DB(29)          30          5╣ ⁿ 60          64           -DB(29) 
  1009.       +DB(30)          31          6▒ ⁿ 62          65           -DB(30) 
  1010.       +DB(31)          32          6│ ⁿ 64          66           -DB(31) 
  1011.       +DB(P3)          33          6╡ ⁿ 66          67           -DB(P3) 
  1012.       GROUND           34          6╖ ⁿ 68          68           GROUN─  
  1013. ==============================================================================
  1014. .aw on
  1015.  
  1016. NOTE║  Thσ conducto≥ numbe≥ refer≤ t∩ thσ conducto≥ positioε wheε usinτ 0.02╡-ì
  1017. incΦ centerlinσ fla⌠ ribboε cable«  Othe≥ cablσ type≤ ma∙ bσ useΣ t∩ implemen⌠ ì
  1018. equivalen⌠ contac⌠ assignments.
  1019.  
  1020. .lm 3
  1021. ááIMPLEMENTOR╙ NOTE║  X3T9.▓ i≤ documentinτ aε alternatσ 1╢-bi⌠ singlσ-cablσ ì
  1022. áásolutioε anΣ aε alternatσ 3▓-bi⌠ solutioε anΣ expect≤ t∩ bσ ablσ t∩ removσ ì
  1023. ááthσ ┬ cablσ definitioε iε ß futurσ versioε oµ SCSI.
  1024. .lm 1
  1025.  
  1026. .cp 20è.aw off
  1027. .pm 0
  1028. 4.4. Electrica∞ Description
  1029. .aw on
  1030. .pm 3
  1031.  
  1032. ááFo≥ thσ measurement≤ iε thi≤ section¼ SCS╔ bu≤ terminatioε i≤ assumeΣ t∩ bσ ì
  1033. externa∞ t∩ thσ SCS╔ device«  Seσ 4.4.▒ fo≥ thσ terminatinτ requirement≤ fo≥ ì
  1034. thσ RESERVE─ lines«  SCS╔ device≤ ma∙ havσ thσ provisioε fo≥ allowinτ optiona∞ ì
  1035. interna∞ termination.
  1036. .pm 3
  1037. .lm 1
  1038.  
  1039. .cp 10
  1040. .aw off
  1041. .pm 0
  1042. 4.4.1. Singlσ-EndeΣ Alternative
  1043. .aw on
  1044. .pm 3
  1045.  
  1046. ááAl∞ signal≤ no⌠ defineΣ a≤ RESERVED¼ GROUND¼ o≥ TERMPW╥ shal∞ bσ terminateΣ ì
  1047. a⌠ botΦ end≤ oµ thσ cable«  Thσ implemento≥ ma∙ choosσ onσ oµ thσ followinτ ì
  1048. tw∩ method≤ t∩ terminatσ eacΦ enΣ (seσ Figurσ ┤-9):
  1049.  
  1050. áá(1⌐ Thσ terminatioε oµ eacΦ signa∞ shal∞ consis⌠ oµ 22░ ohm≤ (+_5%⌐ t∩ thσ ì
  1051. TERMPW╥ linσ anΣ 33░ ohm≤ (+_5%⌐ t∩ ground«  Usinτ resistor≤ witΦ +_1Ñ tolerancσ ì
  1052. improve≤ noisσ margins.
  1053. áá(2⌐ Thσ terminatioε oµ eacΦ signa∞ shal∞ mee⌠ thesσ requirements:
  1054. .pm 6
  1055. .lm 3
  1056. ááááá(a⌐ Thσ terminator≤ shal∞ eacΦ suppl∙ ß characteristiπ impedancσ betweeε ì
  1057. áá10░ anΣ 13▓ ohms« 
  1058. ááááá(b⌐ Thσ terminator≤ shal∞ bσ powereΣ b∙ thσ TERMPW╥ linσ anΣ ma∙ receivσ ì
  1059. ááadditiona∞ powe≥ froφ othe≥ source≤ bu⌠ shal∞ no⌠ requirσ sucΦ additiona∞ ì
  1060. áápowe≥ fo≥ prope≥ operatioε (seσ 4.4.3).
  1061. ááááá(c⌐ Thσ curren⌠ availablσ t∩ an∙ signa∞ linσ drive≥ shal∞ no⌠ exceeΣ ì
  1062. áá48millΘamp≤ wheε thσ drive≥ assert≤ thσ linσ anΣ pull≤ i⌠ t∩ 0.╡ volt≤ dc«  ì
  1063. ááOnl∙ 44.╕ m┴ oµ thi≤ curren⌠ shal∞ bσ availablσ froφ thσ tw∩ terminators.
  1064. ááááá(d⌐ Thσ voltagσ oε al∞ releaseΣ signa∞ line≤ shal∞ bσ a⌠ leas⌠ 2.╡ volt≤ ì
  1065. áádπ wheε thσ TERMPW╥ linσ i≤ withiε specifieΣ value≤ (seσ 4.4.3)« 
  1066. ááááá(e⌐ Thesσ condition≤ shal∞ bσ me⌠ witΦ an∙ lega∞ configuratioε oµ target≤ ì
  1067. ááanΣ initiator≤ a≤ lonτ a≤ a⌠ leas⌠ onσ devicσ i≤ supplyinτ TERMPWR.
  1068. .pm 3
  1069. .lm 1
  1070.  
  1071. ááThσ firs⌠ terminatioε methoΣ abovσ i≤ thσ samσ a≤ iε SCS╔-1«  Thσ seconΣ ì
  1072. terminatioε methoΣ i≤ recommendeΣ fo≥ bette≥ signa∞ quality.
  1073.  
  1074. .cp 5
  1075. .aw off
  1076. .pm 0
  1077. 4.4.1.1. Outpu⌠ Characteristics
  1078. .aw on
  1079. .pm 3
  1080. ááAl∞ signal≤ shal∞ usσ opeε-collecto≥ o≥ threσ-statσ drivers«  EacΦ signa∞ ì
  1081. driveε b∙ aε SCS╔ devicσ shal∞ havσ thσ followinτ outpu⌠ characteristic≤ wheε ì
  1082. measureΣ a⌠ thσ SCS╔ device'≤ connector:
  1083. .lm 36
  1084. ááVOL (Low-level output voltage) = 0.░ t∩ 0.╡ volt≤ dπ a⌠ 4╕ m┴ sinkinτ ì
  1085. ááááááááááááááááááááááááááááááááááá(signa∞ assertion)
  1086. .lm 1
  1087. ááVOHû (HigΦ-leve∞ outpu⌠ voltage⌐ ╜ 2.╡ t∩ 5.2╡ volt≤ dπ (signa∞ negation)
  1088.  
  1089. .cp 5
  1090. .aw off
  1091. .pm 0
  1092. 4.4.1.2. Inpu⌠ Characteristics
  1093. .aw on
  1094. .pm 3
  1095. ááSCS╔ device≤ witΦ powe≥ oε shal∞ mee⌠ thσ followinτ electrica∞ ì
  1096. characteristic≤ oε eacΦ signa∞ (includinτ botΦ receiver≤ anΣ passivσ drivers):
  1097. ááVILû (Lo≈-leve∞ inpu⌠ voltage⌐ ╜ 0.░ t∩ 0.╕ volt≤ dπ (signa∞ true)
  1098. ááVIHû (HigΦ-leve∞ inpu⌠ voltage⌐ ╜ 2.░ t∩ 5.2╡ volt≤ dπ (signa∞ false)
  1099. ááIILû (Lo≈-leve∞ inpu⌠ current⌐ ╜ -0.┤ t∩ 0.░ m┴ a⌠ VIû ╜ 0.╡ volt≤ dc
  1100. ááIIHû (HigΦ-leve∞ inpu⌠ current⌐ ╜ 0.░ t∩ 0.▒ m┴ a⌠ VIû ╜ 2.╖ volt≤ dc
  1101. ááMinimuφ inpu⌠ hysteresi≤ ╜ 0.▓ volt≤ dc
  1102. .lm 31
  1103. ááMaximum input capacitance = 2╡ p╞ (measureΣ a⌠ thσ devicσ connecto≥ closes⌠ ì
  1104. áááááááááááááááááááááááááááááát∩ thσ stub¼ iµ any¼ withiε thσ device)
  1105. .lm 1
  1106.  
  1107. .cp 2
  1108. ááI⌠ i≤ recommendeΣ tha⌠ SCS╔ device≤ witΦ powe≥ ofµ als∩ mee⌠ thσ abovσ IILû ì
  1109. anΣ IIHû electrica∞ characteristic≤ oε eacΦ signal.
  1110. èááT∩ achievσ maximuφ noisσ immunit∙ anΣ t∩ assurσ prope≥ operatioε witΦ ì
  1111. comple° cablσ configurations¼ i⌠ i≤ recommendeΣ tha⌠ thσ nomina∞ switchinτ ì
  1112. thresholΣ bσ approximatel∙ 1.┤ volts.
  1113.  
  1114. .cp 10
  1115. .aw off
  1116. .pm 0
  1117. 4.4.2. Differentia∞ Alternative
  1118. .aw on
  1119. .pm 3
  1120.  
  1121. ááAl∞ signal≤ consis⌠ oµ tw∩ line≤ denoteΣ +SIGNA╠ anΣ -SIGNAL«  ┴ signa∞ i≤ ì
  1122. truσ wheε +SIGNA╠ i≤ morσ positivσ thaε -SIGNAL¼ anΣ ß signa∞ i≤ falsσ wheε    ì
  1123. -SIGNA╠ i≤ morσ positivσ thaε +SIGNAL«  Al∞ assigneΣ signal≤ oµ thσ ┴ anΣ ┬ ì
  1124. cable≤ describeΣ iε 4.╢ shal∞ bσ terminateΣ a⌠ eacΦ enΣ oµ thσ cablσ witΦ ß ì
  1125. terminato≥ networδ a≤ showε iε Figurσ ┤-10«  Resisto≥ tolerance≤ iε thσ ì
  1126. terminato≥ networδ shal∞ bσ +_5Ñ o≥ less.
  1127.  
  1128. ááThσ DIFFSEN╙ signa∞ oµ thσ connecto≥ i≤ useΣ a≤ aε activσ higΦ enablσ fo≥ ì
  1129. thσ differentia∞ drivers«  Iµ ß singlσ-endeΣ devicσ o≥ terminato≥ i≤ ì
  1130. inadvertentl∙ connected¼ thi≤ signa∞ i≤ grounded¼ disablinτ thσ differentia∞ ì
  1131. driver≤ (seσ Figurσ ┤-11).
  1132.  
  1133. ááThσ characteristiπ impedancσ oµ differentia∞ terminators i≤ 12▓ ohms.
  1134.  
  1135. .cp 20
  1136. .aw off
  1137. .pm 0
  1138. 4.4.2.1. Outpu⌠ Characteristics
  1139. .aw on
  1140. .pm 3
  1141. ááEacΦ signa∞ driveε b∙ aε SCS╔ devicσ shal∞ havσ thσ followinτ outpu⌠ ì
  1142. characteristic≤ wheε measureΣ a⌠ thσ SCS╔ device'≤ connector:
  1143. .lm 36
  1144. .pm 3
  1145. ááVOL (Low-level output voltage) = 1.╖ ╓ maximuφ a⌠ IOLû (Lo≈-leve∞ outpu⌠ ì
  1146. ááááááááááááááááááááááááááááááááááácurrent⌐ ╜ 5╡ mA.
  1147. .lm 37
  1148. ááVOH (High-level output voltage) = 2.╖ ╓ minimuφ a⌠ IOHû (HigΦ-leve∞ outpu⌠ ì
  1149. áááááááááááááááááááááááááááááááááááácurrent⌐ ╜ -5╡ mA.
  1150. .lm 39
  1151. ááVOD (Differential output voltage) = 1.░ ╓ minimuφ witΦ commoε-modσ voltagσ ì
  1152. áááááááááááááááááááááááááááááááááááááárange≤ froφ -╖ t∩ +1▓ volt≤ dc.
  1153. .lm 1
  1154.  
  1155. ááVOLû anΣ VOHû shal∞ bσ a≤ measureΣ betweeε thσ outpu⌠ termina∞ anΣ thσ SCS╔ ì
  1156. device'≤ logiπ grounΣ reference.
  1157.  
  1158. ááThσ outpu⌠ characteristic≤ shal∞ additionall∙ conforφ t∩ IS╧ 8482.
  1159.  
  1160. .cp 5
  1161. .aw off
  1162. .pm 0
  1163. 4.4.2.2. Inpu⌠ Characteristics
  1164. .aw on
  1165. .pm 3
  1166. ááSCS╔ device≤ shal∞ mee⌠ thσ followinτ electrica∞ characteristic≤ oε eacΦ ì
  1167. signa∞ (includinτ botΦ receiver≤ anΣ passivσ drivers):
  1168. ááIIû (Inpu⌠ curren⌠ oε eithe≥ input⌐ ╜ +▀ 2.░ m┴ maximum.
  1169. ááMaximuφ inpu⌠ capacitancσ ╜ 2╡ pF.
  1170.  
  1171. ááThσ IIû requiremen⌠ shal∞ bσ me⌠ witΦ thσ inpu⌠ voltagσ varyinτ betweeε -╖ ì
  1172. anΣ +1▓ volt≤ dc¼ witΦ powe≥ oε o≥ off¼ anΣ witΦ thσ hysteresi≤ equalinτ 3╡ ì
  1173. millΘvolts¼ minimum.
  1174.  
  1175. ááThσ inpu⌠ characteristic≤ shal∞ additionall∙ conforφ t∩ IS╧ 8482.
  1176.  
  1177. .cp 10è.aw off
  1178. .pm 0
  1179. 4.4.3. Terminato≥ Power
  1180. .aw on
  1181. .pm 3
  1182.  
  1183. ááSCS╔ initiator≤ shal∞ suppl∙ terminato≥ powe≥ t∩ thσ TERMPW╥ contact(s⌐ and¼ ì
  1184. iµ i⌠ implement≤ thσ widσ SCS╔ option¼ t∩ thσ TERMPWR┬ contacts«  Thi≤ powe≥ ì
  1185. shal∞ bσ supplieΣ througΦ ß diodσ o≥ simila≥ semiconducto≥ tha⌠ prevent≤ ì
  1186. backflo≈ oµ powe≥ t∩ thσ SCS╔ device«  Target≤ anΣ SCS╔ device≤ tha⌠ becomσ ì
  1187. temporar∙ initiator≤ (e.g.¼ target≤ whicΦ implemen⌠ thσ COP┘ commanΣ o≥ ì
  1188. asynchronou≤ even⌠ notification⌐ arσ no⌠ requireΣ t∩ suppl∙ terminato≥ power«  ì
  1189. An∙ SCS╔ devicσ ma∙ suppl∙ terminato≥ power«  Interfacσ erro≥ rate≤ arσ lowe≥ ì
  1190. iµ thσ terminatioε voltagσ i≤ maintaineΣ a⌠ thσ extremσ end≤ oµ thσ cable.
  1191.  
  1192. .cp 4
  1193. ááAl∞ terminator≤ independen⌠ oµ locatioε shal∞ bσ powereΣ froφ thσ TERMPW╥ ì
  1194. anΣ TERMPWR┬ contact(s)«  Thσ usσ oµ keyeΣ connector≤ i≤ recommendeΣ iε SCS╔ ì
  1195. device≤ tha⌠ providσ terminato≥ powe≥ t∩ preven⌠ accidenta∞ groundinτ o≥ ì
  1196. thσ incorrec⌠ connectioε oµ terminato≥ power.
  1197.  
  1198. .pm 0
  1199. .lm 3
  1200. ááIMPLEMENTOR╙ NOTE║ Regulator∙ agencie≤ ma∙ requirσ limitinτ maximuφ (shor⌠ ì
  1201. áácircuit⌐ curren⌠ t∩ thσ terminato≥ powe≥ lines«  RecommendeΣ curren⌠ ì
  1202. áálimitinτ i≤ 1.╡ ampere≤ fo≥ TERMPW╥ anΣ ▓ ampere≤ fo≥ TERMPWRB«  Fo≥ system≤ ì
  1203. ááutilizinτ multiplσ initiators¼ thσ initiator≤ ma∙ bσ configureΣ witΦ optioε ì
  1204. áástrap≤ o≥ curren⌠ limitinτ devices«  Maximuφ availablσ curren⌠ shoulΣ no⌠ ì
  1205. ááexceeΣ ╡ amperes.
  1206. .pm 3
  1207. .lm 1
  1208.  
  1209. ááSCS╔ device≤ shal∞ sinδ n∩ morσ thaε 1.░ m┴ froφ TERMPW╥ anΣ n∩ morσ thaε ì
  1210. 1.░ m┴ froφ TERMPWR┬ excep⌠ t∩ powe≥ aε optiona∞ interna∞ terminator.
  1211.  
  1212. .cp 6
  1213. ááSinglσ-endeΣ SCS╔ device≤ providinτ terminato≥ powe≥ oε cablσ ┴ shal∞ havσ ì
  1214. thσ followinτ characteristics:
  1215. ááVTermû ╜ 4.2╡ t∩ 5.2╡ volt≤ dc
  1216. .pm 11
  1217. áááááááááá90░ m┴ minimuφ sourcσ drivσ capability
  1218. .pm 3
  1219.  
  1220. .cp 6
  1221. ááDifferentia∞ SCS╔ device≤ providinτ terminato≥ powe≥ oε cablσ ┴ shal∞ havσ ì
  1222. thσ followinτ characteristics:
  1223. ááVTermû ╜ 4.░ t∩ 5.2╡ volt≤ dc
  1224. .pm 11
  1225. áááááááááá60░ m┴ minimuφ sourcσ drivσ capability
  1226. .pm 3
  1227.  
  1228. .cp 6
  1229. áá Singlσ-endeΣ SCS╔ device≤ providinτ terminato≥ powe≥ oε cablσ ┬ shal∞ havσ ì
  1230. thσ followinτ characteristics:
  1231. ááVTermû ╜ 4.2╡ t∩ 5.2╡ volt≤ dc
  1232. .pm 11
  1233. áááááááááá150░ m┴ minimuφ sourcσ drivσ capability
  1234. .pm3
  1235.  
  1236. .cp 6
  1237. ááDifferentia∞ SCS╔ device≤ providinτ terminato≥ powe≥ oε cablσ ┬ shal∞ havσ ì
  1238. thσ followinτ characteristics:
  1239. ááVTermû ╜ 4.░ t∩ 5.2╡ volt≤ dc
  1240. .pm 11
  1241. áááááááááá100░ m┴ minimuφ sourcσ drivσ capability
  1242. .pm 3
  1243.  
  1244. .lm 3
  1245. ááIMPLEMENTOR╙ NOTE║  I⌠ i≤ recommendeΣ tha⌠ thσ terminato≥ powe≥ line≤ bσ ì
  1246. áádecoupleΣ a⌠ eacΦ terminato≥ witΦ a⌠ leas⌠ ß 2.▓ microfaraΣ higΦ-frequenc∙ ì
  1247. áácapacito≥ t∩ improvσ signa∞ quality.
  1248. .lm 1
  1249.  
  1250. .aw off
  1251. .pm 0
  1252. .cp 54è.. insert Figure 4-9
  1253.  
  1254.  
  1255.  
  1256.  
  1257.  
  1258.  
  1259.  
  1260.  
  1261.  
  1262.  
  1263.  
  1264.  
  1265.  
  1266.  
  1267.  
  1268.  
  1269.  
  1270.  
  1271.  
  1272.                           Alternativσ ▒ Termination
  1273.  
  1274.  
  1275.  
  1276.  
  1277.  
  1278.  
  1279.  
  1280.  
  1281.  
  1282.  
  1283.  
  1284.  
  1285.  
  1286.  
  1287.  
  1288.  
  1289.  
  1290.  
  1291.  
  1292.  
  1293.  
  1294.  
  1295.  
  1296.  
  1297.  
  1298.  
  1299.  
  1300.  
  1301.  
  1302. .. Paul wants to change note 2 to say R2 = 124 ohms.
  1303.  
  1304.  
  1305.                           Alternativσ ▓ Termination
  1306.  
  1307.                Figure 4-9: Termination for Single-Ended Device≤
  1308. .aw on
  1309. .pm 3
  1310. è.aw off
  1311. .pm 0
  1312. .cp 20
  1313. .. insert Figure 4-10
  1314.  
  1315.  
  1316.  
  1317.  
  1318.  
  1319.  
  1320.  
  1321.  
  1322.  
  1323.  
  1324.  
  1325.  
  1326.  
  1327.  
  1328.  
  1329.  
  1330.  
  1331.  
  1332.  
  1333.                Figure 4-10: Termination for Differential Devices
  1334. .aw on
  1335. .pm 3
  1336.  
  1337. .aw off
  1338. .pm 0
  1339. .cp 20
  1340. .. insert Figure 4-11
  1341.  
  1342.  
  1343.  
  1344.  
  1345.  
  1346.  
  1347.  
  1348.  
  1349.  
  1350.  
  1351.  
  1352.  
  1353.  
  1354.  
  1355.  
  1356.  
  1357.  
  1358.  
  1359.  
  1360.               Figure 4-11: Differential Driver Protection Circuit
  1361. .aw on
  1362. .pm 3
  1363.  
  1364. .cp 10
  1365. .aw off
  1366. .pm 0
  1367. 4.4.4. RESERVE─ Lines
  1368. .aw on
  1369. .pm 3
  1370.  
  1371. ááThσ line≤ labeleΣ RESERVE─ iε thσ ┴ cablσ contac⌠ assignmen⌠ table≤ (Tablσ ì
  1372. ┤-▓ anΣ Tablσ ┤-4⌐ shal∞ bσ connecteΣ t∩ grounΣ iε thσ bu≤ terminato≥ ì
  1373. assemblie≤ o≥ iε thσ enΣ device≤ oε thσ SCS╔ cable«  Thσ RESERVE─ line≤ shoulΣ ì
  1374. bσ opeε iε thσ othe≥ SCS╔ devices¼ bu⌠ ma∙ bσ connecteΣ t∩ ground.
  1375.  
  1376. .cp 20è.aw off
  1377. .pm 0
  1378. 4.5. SCS╔ Bus
  1379. .aw on
  1380. .pm 3
  1381.  
  1382. ááCommunicatioε oε thσ SCS╔ bu≤ i≤ alloweΣ betweeε onl∙ tw∩ SCS╔ device≤ a⌠ ì
  1383. an∙ giveε time«  Therσ i≤ ß maximuφ oµ eigh⌠ SCS╔ devices«  EacΦ SCS╔ devicσ ì
  1384. ha≤ aε SCS╔ I─ bi⌠ assigneΣ a≤ showε iε Figurσ ┤-12«  Threσ samplσ systeφ ì
  1385. configuration≤ arσ showε iε Figurσ ┤-13.
  1386.  
  1387. ááWheε tw∩ SCS╔ device≤ communicatσ oε thσ SCS╔ bus¼ onσ act≤ a≤ aε initiato≥ ì
  1388. anΣ thσ othe≥ act≤ a≤ ß target«  Thσ initiato≥ originate≤ aε operatioε anΣ thσ ì
  1389. targe⌠ perform≤ thσ operation«  Aε SCS╔ devicσ usuall∙ ha≤ ß fixeΣ rolσ a≤ aε ì
  1390. initiato≥ o≥ target¼ bu⌠ somσ device≤ ma∙ bσ ablσ t∩ assumσ eithe≥ role.
  1391.  
  1392. ááAε initiato≥ ma∙ addres≤ u≡ t∩ eigh⌠ periphera∞ device≤ tha⌠ arσ connecteΣ ì
  1393. t∩ ß target«  Thσ targe⌠ ma∙ bσ physicall∙ houseΣ withiε thσ periphera∞ devicσ ì
  1394. iε whicΦ casσ thσ periphera∞ devicσ i≤ referreΣ t∩ a≤ aε embeddeΣ SCS╔ device.
  1395.  
  1396. .cp 20
  1397. .aw off
  1398. .pm 0
  1399.      DB(7) DB(6) DB(5) DB(4) DB(3) DB(2) DB(1) DB(0)  <-- DATA BUS
  1400.      |     |     |     |     |     |     |     |
  1401.      |     |     |     |     |     |     |     SCSI ID = 0
  1402.      |     |     |     |     |     |     | 
  1403.      |     |     |     |     |     |     SCSI ID = 1
  1404.      |     |     |     |     |     |
  1405.      |     |     |     |     |     SCSI ID = 2
  1406.      |     |     |     |     |
  1407.      |     |     |     |     SCSI ID = 3
  1408.      |     |     |     |
  1409.      |     |     |     SCSI ID = 4
  1410.      |     |     |
  1411.      |     |     SCSI ID = 5
  1412.      |     |
  1413.      |     SCSI ID = 6
  1414.      |
  1415.      SCSI ID = 7
  1416.  
  1417.  
  1418.  
  1419.                            Figure 4-12: SCSI ID Bits
  1420. .aw on
  1421. .pm 3
  1422.  
  1423. .aw off
  1424. .pm 0
  1425. .cp 54è.. insert Figure 4-13
  1426.  
  1427.  
  1428.  
  1429.  
  1430.  
  1431.  
  1432.  
  1433.  
  1434.  
  1435.  
  1436.  
  1437.  
  1438.  
  1439.  
  1440.  
  1441.  
  1442.  
  1443.  
  1444.  
  1445.  
  1446.  
  1447.  
  1448.  
  1449.  
  1450.  
  1451.  
  1452.  
  1453.  
  1454.  
  1455.  
  1456.  
  1457.  
  1458.  
  1459.  
  1460.  
  1461.  
  1462.  
  1463.  
  1464.  
  1465.  
  1466.  
  1467.  
  1468.  
  1469.  
  1470.  
  1471.  
  1472.  
  1473.  
  1474.  
  1475.  
  1476.  
  1477.  
  1478.  
  1479.                     Figure 4-13: Sample SCSI Configurations
  1480. .aw on
  1481. .pm 3
  1482. è.cp 5
  1483. ááU≡ t∩ eigh⌠ SCS╔ device≤ caε bσ supporteΣ oε thσ SCS╔ bus«  The∙ caε bσ an∙ ì
  1484. combinatioε oµ initiator≤ anΣ target≤ provideΣ therσ i≤ a⌠ leas⌠ onσ oµ each.
  1485.  
  1486. .cp 6
  1487. ááCertaiε SCS╔ bu≤ function≤ arσ assigneΣ t∩ thσ initiato≥ anΣ certaiε SCS╔ ì
  1488. bu≤ function≤ arσ assigneΣ t∩ thσ target«  Thσ initiato≥ ma∙ arbitratσ fo≥ thσ ì
  1489. SCS╔ bu≤ anΣ selec⌠ ß particula≥ target«  Thσ targe⌠ ma∙ reques⌠ thσ transfe≥ ì
  1490. oµ COMMAND¼ DATA¼ STATUS¼ o≥ othe≥ informatioε oε thσ DAT┴ BUS¼ anΣ iε somσ ì
  1491. case≤ i⌠ ma∙ arbitratσ fo≥ thσ SCS╔ bu≤ anΣ reselec⌠ aε initiato≥ fo≥ thσ ì
  1492. purposσ oµ continuinτ aε operation.
  1493.  
  1494. ááInformatioε transfer≤ oε thσ DAT┴ BU╙ arσ asynchronou≤ anΣ follo≈ ß defineΣ ì
  1495. REQ/AC╦ handshakσ protocol«  Onσ bytσ oµ informatioε ma∙ bσ transferreΣ witΦ ì
  1496. eacΦ handshakσ oε thσ ┴ cablσ and¼ iµ thσ widσ datß transfe≥ optioε i≤ ì
  1497. implemented¼ onσ o≥ threσ byte≤ oµ informatioε ma∙ bσ transferreΣ witΦ eacΦ ì
  1498. handshakσ oε thσ ┬ cable«  Aε optioε i≤ defineΣ fo≥ synchronou≤ datß transfer.
  1499.  
  1500. .cp 20
  1501. .aw off
  1502. .pm 0
  1503. 4.6. SCS╔ Bu≤ Signals
  1504. .aw on
  1505. .pm 3
  1506.  
  1507. ááTherσ arσ ß tota∞ oµ 1╕ signal≤ oε thσ ┴ cablσ anΣ 2╣ signal≤ oε thσ ┬ ì
  1508. cable«  ┴ tota∞ oµ 1▒ signal≤ arσ useΣ fo≥ contro∞ anΣ 3╢ arσ useΣ fo≥ datß ì
  1509. (messages¼ commands¼ status¼ anΣ data)¼ includinτ parity«  Thesσ signal≤ arσ ì
  1510. describeΣ a≤ follows:
  1511.  
  1512. .pm 0
  1513. .c≡ 2
  1514. BS┘ (BUSY).é  Aε "O╥-tiedó signa∞ tha⌠ indicate≤ tha⌠ thσ bu≤ i≤ beinτ used.
  1515.  
  1516. .cp 2
  1517. SE╠ (SELECT).é  Aε "O╥-tiedó signa∞ useΣ b∙ aε initiato≥ t∩ selec⌠ ß targe⌠ o≥ ì
  1518. b∙ ß targe⌠ t∩ reselec⌠ aε initiator.
  1519.  
  1520. .cp 4
  1521. .lm 3
  1522. ááIMPLEMENTOR╙ NOTE║  Thσ SE╠ signa∞ wa≤ no⌠ defineΣ a≤ "O╥-tiedó iε SCS╔-1«  ì
  1523. ááI⌠ ha≤ beeε defineΣ a≤ "O╥-tiedó iε SCS╔-▓ iε anticipatioε oµ needinτ ì
  1524. ááanothe≥ "O╥-tiedó signa∞ fo≥ futurσ standardization«  Thi≤ doe≤ no⌠ causσ aε ì
  1525. ááoperationa∞ probleφ iε mixinτ SCS╔-▒ anΣ SCS╔-▓ devices.
  1526. .lm 1
  1527.  
  1528. .cp 2
  1529. C/─  (CONTROL/DATA).é  ┴ signa∞ driveε b∙ ß targe⌠ tha⌠ indicate≤ whethe≥ ì
  1530. CONTRO╠ o≥ DAT┴ informatioε i≤ oε thσ DAT┴ BUS«  Truσ indicate≤ CONTROL.
  1531.  
  1532. .cp 4
  1533. I/╧ (INPUT/OUTPUT).é  ┴ signa∞ driveε b∙ ß targe⌠ tha⌠ control≤ thσ directioε ì
  1534. oµ datß movemen⌠ oε thσ DAT┴ BU╙ witΦ respec⌠ t∩ aε initiator« Truσ indicate≤ ì
  1535. inpu⌠ t∩ thσ initiator«  Thi≤ signa∞ i≤ als∩ useΣ t∩ distinguisΦ betweeε ì
  1536. SELECTIO╬ anΣ RESELECTIO╬ phases.
  1537.  
  1538. .cp 2
  1539. MS╟ (MESSAGE).é  ┴ signa∞ driveε b∙ ß targe⌠ durinτ thσ MESSAG┼ phase.
  1540.  
  1541. .cp 2
  1542. RE╤ (REQUEST).é  ┴ signa∞ driveε b∙ ß targe⌠ oε thσ ┴ cablσ t∩ indicatσ ß ì
  1543. reques⌠ fo≥ ß REQ/AC╦ datß transfe≥ handshake.
  1544.  
  1545. .cp 2
  1546. REQ┬ (REQUEST).é  ┴ signa∞ driveε b∙ ß targe⌠ oε thσ ┬ cablσ t∩ indicatσ ß ì
  1547. reques⌠ fo≥ ß REQB/ACK┬ datß transfe≥ handshake.
  1548.  
  1549. .cp 2
  1550. AC╦ (ACKNOWLEDGE).é  ┴ signa∞ driveε b∙ aε initiato≥ oε thσ ┴ cablσ t∩ indicatσ ì
  1551. aε acknowledgmen⌠ fo≥ ß REQ/AC╦ datß transfe≥ handshake.
  1552.  
  1553. .cp 2
  1554. ACK┬ (ACKNOWLEDGE).é  ┴ signa∞ driveε b∙ aε initiato≥ oε thσ ┬ cablσ t∩ ì
  1555. indicatσ aε acknowledgmen⌠ fo≥ ß REQB/ACK┬ datß transfe≥ handshake.
  1556. è.cp 2
  1557. AT╬ (ATTENTION).é  ┴ signa∞ driveε b∙ aε initiato≥ t∩ indicatσ thσ ATTENTIO╬ ì
  1558. condition.
  1559.  
  1560. .cp 2
  1561. RS╘ (RESET).é  Aε "O╥-tiedó signa∞ tha⌠ indicate≤ thσ RESE╘ condition.
  1562.  
  1563. .cp 6
  1564. DB(╖-0,P⌐ (DAT┴ BUS).é  Eigh⌠ datß-bi⌠ signals¼ plu≤ ß parit∙-bi⌠ signa∞ tha⌠ ì
  1565. forφ ß DAT┴ BUS«  DB(7⌐ i≤ thσ mos⌠ significan⌠ bi⌠ anΣ ha≤ thσ highes⌠ ì
  1566. priorit∙ durinτ thσ ARBITRATIO╬ phase«  Bi⌠ number¼ significance¼ anΣ priorit∙ ì
  1567. decreasσ downwarΣ t∩ DB(0)«  ┴ datß bi⌠ i≤ defineΣ a≤ onσ wheε thσ signa∞ ì
  1568. valuσ i≤ truσ anΣ i≤ defineΣ a≤ zer∩ wheε thσ signa∞ valuσ i≤ false«  Datß ì
  1569. parit∙ DB(P⌐ shal∞ bσ odd«  Parit∙ i≤ undefineΣ durinτ thσ ARBITRATIO╬ phase.
  1570.  
  1571. .cp 6
  1572. DB(3▒-8,P1,P2,P3⌐ (DAT┴ BUS).é  Twent∙-fou≥ datß-bi⌠ signals¼ plu≤ threσ ì
  1573. parit∙-bi⌠ signal≤ tha⌠ forφ aε extensioε t∩ thσ DAT┴ BUS«   DB(P1,P2,P3⌐ arσ ì
  1574. parit∙ bit≤ fo≥ DB(1╡-8)¼ DB(2│-16)¼ anΣ DB(3▒-24⌐ respectively«  ┴ datß bi⌠ ì
  1575. i≤ defineΣ a≤ onσ wheε thσ signa∞ valuσ i≤ truσ anΣ i≤ defineΣ a≤ zer∩ wheε ì
  1576. thσ signa∞ valuσ i≤ false«  Datß parit∙ DB(Px⌐ shal∞ bσ odd«  
  1577. .pm 3
  1578.  
  1579. .cp 10
  1580. .aw off
  1581. .pm 0
  1582. 4.6.1. Signa∞ Values
  1583. .aw on
  1584. .pm 3
  1585.  
  1586. ááSignal≤ ma∙ assumσ truσ o≥ falsσ values«  Therσ arσ tw∩ method≤ oµ drivinτ ì
  1587. thesσ signals«  Iε botΦ cases¼ thσ signa∞ shal∞ bσ activel∙ driveε true¼ o≥ ì
  1588. asserted«  Iε thσ casσ oµ O╥-tieΣ drivers¼ thσ drive≥ doe≤ no⌠ drivσ thσ ì
  1589. signa∞ t∩ thσ falsσ state¼ rathe≥ thσ bia≤ circuitr∙ oµ thσ bu≤ terminator≤ ì
  1590. pull≤ thσ signa∞ falsσ wheneve≥ i⌠ i≤ releaseΣ b∙ thσ driver≤ a⌠ ever∙ SCS╔ ì
  1591. device«  Iµ an∙ drive≥ i≤ asserted¼ theε thσ signa∞ i≤ true«  Iε thσ casσ oµ ì
  1592. noε-O╥-tieΣ drivers¼ thσ signa∞ ma∙ bσ activel∙ driveε false«  Iε thi≤ ì
  1593. standard¼ whereve≥ thσ terφ negateΣ i≤ used¼ i⌠ mean≤ tha⌠ thσ signa∞ ma∙ bσ ì
  1594. activel∙ driveε false¼ o≥ ma∙ bσ simpl∙ releaseΣ (iε whicΦ casσ thσ bia≤ ì
  1595. circuitr∙ pull≤ i⌠ false)¼ a⌠ thσ optioε oµ thσ implementor«  Thσ advantagσ t∩ ì
  1596. activel∙ drivinτ signal≤ falsσ durinτ informatioε transfe≥ i≤ tha⌠ thσ ì
  1597. transitioε froφ truσ t∩ falsσ occur≤ morσ quickl∙ anΣ thσ noisσ margiε i≤ mucΦ ì
  1598. highe≥ thaε iµ thσ signa∞ i≤ simpl∙ released«  Thi≤ facilitate≤ reliablσ datß ì
  1599. transfe≥ a⌠ higΦ rates¼ especiall∙ a⌠ thσ longe≥ cablσ length≤ useΣ witΦ ì
  1600. differentia∞ drivers« 
  1601.  
  1602. .cp 10
  1603. .aw off
  1604. .pm 0
  1605. 4.6.2. O╥-TieΣ Signals
  1606. .aw on
  1607. .pm 3
  1608.  
  1609. ááThσ BSY¼ SEL¼ anΣ RS╘ signal≤ shal∞ bσ O╥-tieΣ only«  Iε thσ ordinar∙ ì
  1610. operatioε oµ thσ bus¼ thσ BS┘ anΣ RS╘ signal≤ ma∙ bσ simultaneousl∙ driveε ì
  1611. truσ b∙ severa∞ drivers«  N∩ signal≤ othe≥ thaε BSY¼ RST¼ anΣ DB(P⌐ arσ ì
  1612. simultaneousl∙ driveε b∙ tw∩ o≥ morσ drivers¼ anΣ an∙ signa∞ othe≥ thaε BSY¼ ì
  1613. SEL¼ anΣ RS╘ ma∙ emplo∙ O╥-tieΣ o≥ noε-O╥-tieΣ drivers«  DB(P⌐ shal∞ no⌠ bσ ì
  1614. driveε falsσ durinτ thσ ARBITRATIO╬ phasσ bu⌠ ma∙ bσ driveε falsσ iε othe≥ ì
  1615. phases«  Therσ i≤ n∩ operationa∞ probleφ iε mixinτ O╥-tieΣ anΣ noε-O╥-tieΣ ì
  1616. driver≤ oε signal≤ othe≥ thaε BS┘ anΣ RST.
  1617.  
  1618. .cp 10è.aw off
  1619. .pm 0
  1620. 4.6.3. Signa∞ Sources
  1621. .aw on
  1622. .pm 3
  1623.  
  1624. ááTablσ ┤-╢ indicate≤ whicΦ typσ oµ SCS╔ devicσ i≤ alloweΣ t∩ sourcσ eacΦ ì
  1625. signal«  N∩ attemp⌠ i≤ madσ t∩ sho≈ iµ thσ sourcσ i≤ drivinτ asserted¼ drivinτ ì
  1626. negated¼ o≥ i≤ passive«  Al∞ SCS╔ devicσ driver≤ tha⌠ arσ no⌠ activσ source≤ ì
  1627. shal∞ bσ iε thσ passivσ state«  Thσ RS╘ signa∞ ma∙ bσ asserteΣ b∙ an∙ SCS╔ ì
  1628. devicσ a⌠ an∙ time.
  1629.  
  1630. .cp 20
  1631. .aw off
  1632. .pm 0
  1633.  
  1634.                           Table 4-6: Signal Sources
  1635.  
  1636. ==============================================================================
  1637.                          A Cable Signal≤                B Cable Signals
  1638.                  ------------------------------¡    -----------------------¡
  1639.                              C/D,
  1640.                              I/O¼
  1641.                              MSG¼  ACK¼  DB(7-0⌐                DB(31-8),
  1642.   Bus Phasσ      BSY   SEL   REQ   ATN   DB(P)      REQ┬  ACK┬  DB(P1,P2,P3⌐
  1643.   ----------¡    ---¡  ---¡  ---¡  ---¡  -------    ---¡  ---¡  ------------
  1644.   BUS FREE       None  None  None  None  None       None  None  None
  1645.   ARBITRATIO╬    All   Wiε   None  None  S I─       None  None  None
  1646.   SELECTION      I&T   Ini⌠  None  Init  Init       None  None  None
  1647.   RESELECTION    I&T   Tarτ  Targ  Init  Targ       None  None  None
  1648.   COMMAND        Targ  None  Targ  Init  Ini⌠       None  None  None
  1649.   DATA IN        Targ  None  Targ  Init  Targ       Targ  Init  Targ
  1650.   DATA OU╘       Targ  None  Targ  Init  Init       Targ  Init  Init
  1651.   STATUS         Targ  None  Targ  Init  Targ       None  None  None
  1652.   MESSAGE IN     Targ  None  Targ  Init  Targ       None  None  None
  1653.   MESSAGE OUT    Targ  None  Targ  Init  Init       Nonσ  Nonσ  Nonσ
  1654. ==============================================================================
  1655. .aw on
  1656. .pm 3
  1657.  
  1658. .lm 9
  1659. .pm 1
  1660.  
  1661. .cp 2
  1662. All:    Thσ signa∞ shal∞ bσ driveε b∙ al∞ SCS╔ device≤ tha⌠ arσ activel∙ ì
  1663. ááááááááarbitrating.
  1664.  
  1665. .cp 5
  1666. S ID:   ┴ uniquσ datß bi⌠ (thσ SCS╔ ID⌐ shal∞ bσ driveε b∙ eacΦ SCS╔ devicσ ì
  1667. áááááááátha⌠ i≤ activel∙ arbitrating╗ thσ othe≥ seveε datß bit≤ shal∞ bσ ì
  1668. ááááááááreleaseΣ (i.e.¼ no⌠ driven⌐ b∙ thi≤ SCS╔ device«  Thσ parit∙ bi⌠ ì
  1669. áááááááá(DB(P)⌐ ma∙ bσ releaseΣ o≥ driveε t∩ thσ truσ state¼ bu⌠ shal∞ neve≥ ì
  1670. áááááááábσ driveε t∩ thσ falsσ statσ durinτ thi≤ phase.
  1671.  
  1672. .cp 2
  1673. I&T:    Thσ signa∞ shal∞ bσ driveε b∙ thσ initiator¼ target¼ o≥ both¼ a≤ ì
  1674. ááááááááspecifieΣ iε thσ SELECTIO╬ phasσ anΣ RESELECTIO╬ phase.
  1675.  
  1676. .cp 2
  1677. Init:   Iµ driven¼ thi≤ signa∞ shal∞ bσ driveε onl∙ b∙ thσ activσ initiator.
  1678.  
  1679. .cp 3
  1680. None:   Thσ signa∞ shal∞ bσ released╗ tha⌠ is¼ no⌠ bσ driveε b∙ an∙ SCS╔ ì
  1681. áááááááádevice«  Thσ bia≤ circuitr∙ oµ thσ bu≤ terminator≤ pull≤ thσ signa∞ t∩ ì
  1682. ááááááááthσ falsσ state.
  1683.  
  1684. .cp 2
  1685. Win:    Thσ signa∞ shal∞ bσ driveε b∙ thσ onσ SCS╔ devicσ tha⌠ win≤ ì
  1686. ááááááááarbitration.
  1687.  
  1688. .cp 2
  1689. Targ:   Iµ thσ signa∞ i≤ driven¼ i⌠ shal∞ bσ driveε onl∙ b∙ thσ activσ target.
  1690. .lm 1
  1691. .pm 3
  1692. è
  1693. .cp 20
  1694. .aw off
  1695. .pm 0
  1696. 4.7. SCS╔ Bu≤ Timing
  1697. .aw on
  1698. .pm 3
  1699.  
  1700. ááUnles≤ otherwisσ indicated¼ thσ dela∙-timσ measurement≤ fo≥ eacΦ SCS╔ ì
  1701. device¼ showε iε Tablσ ┤-7¼ shal∞ bσ calculateΣ froφ signa∞ condition≤ ì
  1702. existinτ a⌠ tha⌠ SCS╔ device'≤ owε SCS╔ bu≤ connection«  Thus¼ thesσ ì
  1703. measurement≤ (excep⌠ cablσ ske≈ delay⌐ caε bσ madσ withou⌠ considerinτ delay≤ ì
  1704. iε thσ cable«  Thσ timinτ characteristic≤ oµ eacΦ signa∞ arσ describeΣ iε thσ ì
  1705. followinτ paragraphs.
  1706.  
  1707. .cp 25
  1708. .pm 1
  1709. .aw off
  1710.                       Table 4-7: SCS╔ Bu≤ Timinτ Values
  1711.  
  1712.         ==============================================================
  1713.         Arbitratioε Dela∙ . . . . . . . « 2.4 microseconds
  1714.         Assertioε PerioΣ  . . . . . . . .  9░ nanoseconds
  1715.         Bu≤ Clea≥ Dela∙ . . . . . . . . . 80░ nanoseconds
  1716.         Bu≤ Freσ Dela∙  . . . . . . . . . 80░ nanoseconds
  1717.         Bu≤ Se⌠ Dela∙ . . . . . . . . . . 1.╕ microseconds
  1718.         Bu≤ Settlσ Dela∙  . . . . . . . . 40░ nanoseconds
  1719.         Cablσ Ske≈ Dela∙  . . . . . . . .  1░ nanoseconds
  1720.         Datß Releasσ Dela∙  . . . . . . . 40░ nanoseconds
  1721.         Deske≈ Dela∙  . . . . . . . . . .  4╡ nanoseconds  
  1722.         Disconnectioε Dela∙ . . . . . . . 20░ microseconds
  1723.         HolΣ Timσ . . . . . . . . . . . .  4╡ nanoseconds
  1724.         Negatioε PerioΣ . . . . . . . . .  9░ nanoseconds
  1725.         Power-Oε t∩ Selectioε Timσ  . . .  1░ second≤ recommended
  1726.         Reset t∩ Selectioε Time . . . . . 25░ millisecond≤ recommended
  1727.         Rese⌠ HolΣ Timσ . . . . . . . . .  2╡ microseconds
  1728.         Selectioε Abor⌠ Timσ  . . . . . . 20░ microseconds
  1729.         Selectioε Time-out Dela∙  . . . . 25░ milliseconds recommended
  1730.         Transfe≥ PerioΣ . . . . . . . . . se⌠ durinτ ßε SDTR messagσ
  1731.         Fas⌠ Assertioε PerioΣ . . . . . .  3░ nanoseconds
  1732.         Fas⌠ Cablσ Ske≈ Dela∙ . . . . . .   ╡ nanoseconds
  1733.         Fas⌠ Deske≈ Dela∙ . . . . . . . .  2░ nanoseconds
  1734.         Fas⌠ HolΣ Timσ  . . . . . . . . .  1░ nanoseconds
  1735.         Fas⌠ Negatioε PerioΣ  . . . . . .  3░ nanoseconds
  1736.         ==============================================================
  1737. .aw on
  1738. .pm 3
  1739.  
  1740.  
  1741. .cp 10
  1742. .aw off
  1743. .pm 0
  1744. 4.7.1. Arbitratioε Dela∙ 
  1745. .aw on
  1746. .pm 3
  1747.  
  1748. ááThσ minimuφ timσ aε SCS╔ devicσ shal∞ wai⌠ froφ assertinτ BS┘ fo≥ ì
  1749. arbitratioε unti∞ thσ DAT┴ BU╙ caε bσ examineΣ t∩ seσ iµ arbitratioε ha≤ beeε ì
  1750. won«  Therσ i≤ n∩ maximuφ time.
  1751.  
  1752. .cp 10
  1753. .aw off
  1754. .pm 0
  1755. 4.7.2. Assertioε PerioΣ 
  1756. .aw on
  1757. .pm 3
  1758.  
  1759. ááThσ minimuφ timσ tha⌠ ß targe⌠ shal∞ asser⌠ RE╤ (o≥ REQB⌐ whilσ usinτ ì
  1760. synchronou≤ datß transfers«  Also¼ thσ minimuφ timσ tha⌠ aε initiato≥ shal∞ ì
  1761. asser⌠ AC╦ (o≥ ACKB⌐ whilσ usinτ synchronou≤ datß transfers«  REQ┬ anΣ ACK┬ ì
  1762. timing≤ onl∙ appl∙ t∩ optiona∞ widσ datß transfers« 
  1763. .pm0
  1764.  
  1765. .cp 10è.aw off
  1766. .pm 0
  1767. 4.7.3. Bu≤ Clea≥ Dela∙ 
  1768. .aw on
  1769. .pm 3
  1770.  
  1771. ááThσ maximuφ timσ fo≥ aε SCS╔ devicσ t∩ sto≡ drivinτ al∞ bu≤ signal≤ after:
  1772. .lm 3
  1773. áá(1⌐ Thσ BU╙ FRE┼ phasσ i≤ detecteΣ (BS┘ anΣ SE╠ botΦ falsσ fo≥ ß bu≤ settlσ ì
  1774. áádelay)
  1775. áá(2⌐ SE╠ i≤ receiveΣ froφ anothe≥ SCS╔ devicσ durinτ thσ ARBITRATIO╬ phase
  1776. áá(3⌐ Thσ transitioε oµ RS╘ t∩ true.
  1777. .lm 1
  1778.  
  1779. ááFo≥ thσ firs⌠ conditioε above¼ thσ maximuφ timσ fo≥ aε SCS╔ devicσ t∩ clea≥ ì
  1780. thσ bu≤ i≤ 120░ nanosecond≤ froφ BS┘ anΣ SE╠ firs⌠ becominτ botΦ false«  Iµ aε ì
  1781. SCS╔ devicσ require≤ morσ thaε ß bu≤ settlσ dela∙ t∩ detec⌠ BU╙ FRE┼ phase¼ i⌠ ì
  1782. shal∞ clea≥ thσ bu≤ withiε ß bu≤ clea≥ dela∙ minu≤ thσ exces≤ time.
  1783.  
  1784. .cp 10
  1785. .aw off
  1786. .pm 0
  1787. 4.7.4. Bu≤ Freσ Dela∙ 
  1788. .aw on
  1789. .pm 3
  1790.  
  1791. ááThσ minimuφ timσ tha⌠ aε SCS╔ devicσ shal∞ wai⌠ froφ it≤ detectioε oµ thσ ì
  1792. BU╙ FRE┼ phasσ (BS┘ anΣ SE╠ botΦ falsσ fo≥ ß bu≤ settlσ delay⌐ unti∞ it≤ ì
  1793. assertioε oµ BS┘ wheε goinτ t∩ thσ ARBITRATIO╬ phase.
  1794.  
  1795. .cp 10
  1796. .aw off
  1797. .pm 0
  1798. 4.7.5. Bu≤ Se⌠ Dela∙ 
  1799. .aw on
  1800. .pm 3
  1801.  
  1802. ááThσ maximuφ timσ fo≥ aε SCS╔ devicσ t∩ asser⌠ BS┘ anΣ it≤ SCS╔ I─ bi⌠ oε thσ ì
  1803. DAT┴ BU╙ afte≥ i⌠ detect≤ BU╙ FRE┼ phasσ (BS┘ anΣ SE╠ botΦ falsσ fo≥ ß bu≤ ì
  1804. settlσ delay⌐ fo≥ thσ purposσ oµ enterinτ thσ ARBITRATIO╬ phase.
  1805.  
  1806. .cp 10
  1807. .aw off
  1808. .pm 0
  1809. 4.7.6. Bu≤ Settlσ Dela∙ 
  1810. .aw on
  1811. .pm 3
  1812.  
  1813. ááThσ minimuφ timσ t∩ wai⌠ fo≥ thσ bu≤ t∩ settlσ afte≥ changinτ certaiε ì
  1814. contro∞ signal≤ a≤ calleΣ ou⌠ iε thσ protoco∞ definitions.
  1815.  
  1816. .cp 10
  1817. .aw off
  1818. .pm 0
  1819. 4.7.7. Cablσ Ske≈ Dela∙ 
  1820. .aw on
  1821. .pm 3
  1822.  
  1823. ááThσ maximuφ differencσ iε propagatioε timσ alloweΣ betweeε an∙ tw∩ SCS╔ bu≤ ì
  1824. signal≤ measureΣ betweeε an∙ tw∩ SCS╔ devices.
  1825.  
  1826. .cp 10
  1827. .aw off
  1828. .pm 0
  1829. 4.7.8. Datß Releasσ Dela∙ 
  1830. .aw on
  1831. .pm 3
  1832.  
  1833. ááThσ maximuφ timσ fo≥ aε initiato≥ t∩ releasσ thσ DAT┴ BU╙ signal≤ followinτ ì
  1834. thσ transitioε oµ thσ I/╧ signa∞ froφ falsσ t∩ true.
  1835.  
  1836. .cp 10
  1837. .aw off
  1838. .pm 0
  1839. 4.7.9. Deske≈ Dela∙ 
  1840. .aw on
  1841. .pm 3
  1842.  
  1843. ááThσ minimuφ timσ requireΣ fo≥ deske≈ oµ certaiε signals.
  1844. .pm0
  1845.  
  1846. .cp 10
  1847. .aw off
  1848. .pm 0
  1849. 4.7.10. Disconnectioε Dela∙ 
  1850. .aw on
  1851. .pm 3
  1852.  
  1853. ááThσ minimuφ timσ tha⌠ ß targe⌠ shal∞ wai⌠ afte≥ releasinτ BS┘ beforσ ì
  1854. participatinτ iε aε ARBITRATIO╬ phasσ wheε honorinτ ß DISCONNEC╘ messagσ froφ ì
  1855. thσ initiator.
  1856.  
  1857. .cp 10è.aw off
  1858. .pm 0
  1859. 4.7.11. HolΣ Timσ 
  1860. .aw on
  1861. .pm 3
  1862.  
  1863. ááThσ minimuφ timσ addeΣ betweeε thσ assertioε oµ RE╤ (o≥ REQB⌐ o≥ AC╦ (o≥ ì
  1864. ACKB⌐ anΣ thσ changinτ oµ thσ datß line≤ t∩ providσ holΣ timσ iε thσ initiato≥ ì
  1865. o≥ targe⌠ whilσ usinτ synchronou≤ datß transfers«  REQ┬ anΣ ACK┬ timing≤ onl∙ ì
  1866. appl∙ t∩ optiona∞ widσ datß transfers« 
  1867.  
  1868. .cp 10
  1869. .aw off
  1870. .pm 0
  1871. 4.7.12. Negatioε PerioΣ 
  1872. .aw on
  1873. .pm 3
  1874.  
  1875. ááThσ minimuφ timσ tha⌠ ß targe⌠ shal∞ negatσ RE╤ (o≥ REQB⌐ whilσ usinτ ì
  1876. synchronou≤ datß transfers«  Also¼ thσ minimuφ timσ tha⌠ aε initiato≥ shal∞ ì
  1877. negatσ AC╦ (o≥ ACKB⌐ whilσ usinτ synchronou≤ datß transfers«  REQ┬ anΣ ACK┬ ì
  1878. timing≤ onl∙ appl∙ t∩ optiona∞ widσ datß transfers« 
  1879.  
  1880. .cp 10
  1881. .aw off
  1882. .pm 0
  1883. 4.7.13. Power-Oε t∩ Selectioε Time 
  1884. .aw on
  1885. .pm 3
  1886.  
  1887. ááThσ recommendeΣ maximuφ timσ froφ powe≥ applicatioε unti∞ aε SCS╔ targe⌠ i≤ ì
  1888. ablσ t∩ responΣ witΦ appropriatσ statu≤ anΣ sensσ datß t∩ thσ TES╘ UNI╘ READY¼ ì
  1889. INQUIRY¼ anΣ REQUES╘ SENS┼ commands.
  1890.  
  1891. .cp 10
  1892. .aw off
  1893. .pm 0
  1894. 4.7.14. Reset t∩ Selectioε Time 
  1895. .aw on
  1896. .pm 3
  1897.  
  1898. ááThσ recommendeΣ maximuφ timσ afte≥ ß harΣ RESE╘ conditioε unti∞ aε SCS╔ ì
  1899. targe⌠ i≤ ablσ t∩ responΣ witΦ appropriatσ statu≤ anΣ sensσ datß t∩ thσ TES╘ ì
  1900. UNI╘ READY¼ INQUIRY¼ anΣ REQUES╘ SENS┼ commands.
  1901.  
  1902. .cp 10
  1903. .aw off
  1904. .pm 0
  1905. 4.7.15. Rese⌠ HolΣ Timσ 
  1906. .aw on
  1907. .pm 3
  1908.  
  1909. ááThσ minimuφ timσ fo≥ whicΦ RS╘ i≤ asserted«  Therσ i≤ n∩ maximuφ time.
  1910.  
  1911. .cp 10
  1912. .aw off
  1913. .pm 0
  1914. 4.7.16. Selectioε Abor⌠ Timσ 
  1915. .aw on
  1916. .pm 3
  1917.  
  1918. ááThσ maximuφ timσ tha⌠ ß targe⌠ (o≥ initiator⌐ shal∞ takσ froφ it≤ mos⌠ ì
  1919. recen⌠ detectioε oµ beinτ selecteΣ (o≥ reselected⌐ unti∞ assertinτ ß BS┘ ì
  1920. response«  Thi≤ timσ-ou⌠ i≤ requireΣ t∩ ensurσ tha⌠ ß targe⌠ (o≥ initiator⌐ ì
  1921. doe≤ no⌠ asser⌠ BS┘ afte≥ ß SELECTIO╬ (o≥ RESELECTION⌐ phasσ ha≤ beeε aborted«  ì
  1922. Thi≤ i≤ no⌠ thσ selectioε timσ-ou⌠ period╗ seσ 5.1.3.▒ anΣ 5.1.4.▓ fo≥ ß ì
  1923. completσ description.
  1924.  
  1925. .cp 10
  1926. .aw off
  1927. .pm 0
  1928. 4.7.17. Selectioε Time-out Dela∙ 
  1929. .aw on
  1930. .pm 3
  1931.  
  1932. ááThσ minimuφ timσ tha⌠ aε initiato≥ (o≥ target⌐ shoulΣ wai⌠ fo≥ ß BS┘ ì
  1933. responsσ durinτ thσ SELECTIO╬ (o≥ RESELECTION⌐ phasσ beforσ startinτ thσ timσ-ì
  1934. ou⌠ procedure«  Notσ tha⌠ thi≤ i≤ onl∙ ß recommendeΣ timσ period.
  1935.  
  1936. .cp 10
  1937. .aw off
  1938. .pm 0
  1939. 4.7.18. Transfe≥ PerioΣ 
  1940. .aw on
  1941. .pm 3
  1942.  
  1943. ááThσ Transfe≥ PerioΣ specifie≤ thσ minimuφ timσ alloweΣ betweeε thσ leadinτ ì
  1944. edge≤ oµ successivσ RE╤ pulse≤ anΣ oµ successivσ AC╦ pulse≤ whilσ usinτ ì
  1945. synchronou≤ datß transfers«  (Seσ 5.1.5.▓ anΣ 5.6.21.)
  1946.  
  1947. .cp 20è.aw off
  1948. .pm 0
  1949. 4.8. Fas⌠ Synchronou≤ Transfe≥ Option
  1950. .aw on
  1951. .pm 3
  1952.  
  1953. ááWheε device≤ negotiatσ ß synchronou≤ datß transfe≥ perioΣ oµ les≤ thaε 20░ ì
  1954. n≤ the∙ arσ saiΣ t∩ bσ usinτ "fas⌠ synchronou≤ datß transfers"«  Device≤ whicΦ ì
  1955. negotiatσ ß synchronou≤ datß transfe≥ perioΣ greate≥ thaε 20░ n≤ usσ timinτ ì
  1956. parameter≤ specifieΣ iε 4.7«  Wheε ß fas⌠ synchronou≤ datß transfe≥ perioΣ i≤ ì
  1957. negotiated¼ thosσ specifiπ time≤ redefineΣ iε thi≤ sectioε arσ used╗ thosσ no⌠ ì
  1958. redefineΣ remaiε thσ same«  Thσ minimuφ synchronou≤ datß transfe≥ perioΣ i≤ ì
  1959. 10░ ns.
  1960.  
  1961. .cp 10
  1962. .aw off
  1963. .pm 0
  1964. 4.8.1. Fas⌠ Assertioε PerioΣ 
  1965. .aw on
  1966. .pm 3
  1967.  
  1968. ááThi≤ valuσ i≤ thσ minimuφ timσ tha⌠ ß targe⌠ shal∞ asser⌠ RE╤ (o≥ REQB⌐ ì
  1969. whilσ usinτ fas⌠ synchronou≤ datß transfers«  Also¼ thσ minimuφ timσ tha⌠ aε ì
  1970. initiato≥ shal∞ asser⌠ AC╦ (o≥ ACKB⌐ whilσ usinτ fas⌠ synchronou≤ datß ì
  1971. transfers«  REQ┬ anΣ ACK┬ timing≤ onl∙ appl∙ t∩ optiona∞ widσ datß transfers« 
  1972.  
  1973. .cp 10
  1974. .aw off
  1975. .pm 0
  1976. 4.8.2. Fas⌠ Cablσ Ske≈ Dela∙ 
  1977. .aw on
  1978. .pm 3
  1979.  
  1980. ááThi≤ valuσ i≤ thσ maximuφ differencσ iε propagatioε timσ alloweΣ betweeε an∙ ì
  1981. tw∩ SCS╔ bu≤ signal≤ measureΣ betweeε an∙ tw∩ SCS╔ device≤ whilσ usinτ fas⌠ ì
  1982. synchronou≤ datß transfers.
  1983.  
  1984. .cp 10
  1985. .aw off
  1986. .pm 0
  1987. 4.8.3. Fas⌠ Deske≈ Dela∙ 
  1988. .aw on
  1989. .pm 3
  1990.  
  1991. ááThi≤ valuσ i≤ thσ minimuφ timσ requireΣ fo≥ deske≈ oµ certaiε signal≤ whilσ ì
  1992. usinτ fas⌠ synchronou≤ datß transfers.
  1993.  
  1994. .cp 10
  1995. .aw off
  1996. .pm 0
  1997. 4.8.4. Fas⌠ HolΣ Timσ 
  1998. .aw on
  1999. .pm 3
  2000.  
  2001. ááThi≤ valuσ i≤ thσ minimuφ timσ addeΣ betweeε thσ assertioε oµ RE╤ (o≥ REQB⌐ ì
  2002. o≥ AC╦ (o≥ ACKB⌐ anΣ thσ changinτ oµ thσ datß line≤ t∩ providσ holΣ timσ iε ì
  2003. thσ initiato≥ o≥ target¼ respectively¼ whilσ usinτ fas⌠ synchronou≤ datß ì
  2004. transfers«  REQ┬ anΣ ACK┬ timing≤ onl∙ appl∙ t∩ optiona∞ widσ datß transfers« 
  2005.  
  2006. .cp 10
  2007. .aw off
  2008. .pm 0
  2009. 4.8.5. Fas⌠ Negatioε PerioΣ 
  2010. .aw on
  2011. .pm 3
  2012.  
  2013. ááThi≤ valuσ i≤ thσ minimuφ timσ tha⌠ ß targe⌠ shal∞ negatσ RE╤ (o≥ REQB⌐ ì
  2014. whilσ usinτ fas⌠ synchronou≤ datß transfers«  Also¼ thσ minimuφ timσ tha⌠ aε ì
  2015. initiato≥ shal∞ negatσ AC╦ (o≥ ACKB⌐ whilσ usinτ fas⌠ synchronou≤ datß ì
  2016. transfers«  REQ┬ anΣ ACK┬ timing≤ onl∙ appl∙ t∩ optiona∞ widσ datß transfers« 
  2017. ..end of section
  2018. .paè