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HD64180.BUG
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Last update: 02/09/86
HD64180.BUG
V 1.0
I believe the following section was written by:
WA7GXD
(See Gateway Vol 2, No 11. Jan. 24, 1986)
Iµá yo⌡á arσ planninτ oε usinτ ß HitachΘ HD6418░ (gues≤á yo⌡ ì
havσ t∩ usσ HitachΘ iµ yo⌡ plaε oε usinτ ß 64180...⌐ pleasσá notσ ì
tha⌠ i⌠ i≤ no⌠ directl∙ compatiblσ witΦ Z8░ (tm⌐ stylσ periphera∞ ì
IC≤ wheε usinτ thσ Modσ ▓ interrup⌠ scheme«á ╔ know╗ ╔ founΣ ou⌠ ì
thσ hard¼ expensivσ way.
╔á havσá designeΣ ß packe⌠ switcΦ fo≥ Amateu≥á packe⌠á radi∩ ì
usagσ tha⌠ i≤ baseΣ oε thσ 64180¼ ß PIO¼ ß pai≥ oµ SIO/2≤ anΣ thσ ì
NCR538░ SCS╔ chip«á I⌠ als∩ ha≤ 1╢ bytewidσ socket≤ anΣ screw≤ oε ì
thσá sidσ oµ ß 5.25ó flopp∙ disδ controller«á I⌠ i≤ oε ß 4-laye≥ ì
boarΣá anΣ wσ haΣ prototypσ board≤ madσ (compileΣ i≤ thσá neares⌠ ì
softwarσá equivalent...)«á Durinτ fina∞ hardwarσ debuτá testing¼ ì
modσ ▓ interrupt≤ werσ switcheΣ on.
Thσ periphera∞ woulΣ servicσ exactl∙ ▒ interrupt¼á theε locδ ì
it≤ IE╧ linσ lo≈ anΣ sta∙ tha⌠ wa∙ unti∞ powe≥ off/powe≥ oε rese⌠ ì
wa≤ accomplished!
I⌠á turn≤á ou⌠ tha⌠ thσ timinτ oµ thσ LIR¬ outpu⌠á froφá thσ ì
6418░á need≤ t∩ bσ delayeΣ (undocumenteΣ requiremen⌠ oµá thσá Z8░ ì
(tm⌐á peripherals!)«á HitachΘ ha≤ ß simplσ circui⌠ t∩á accomplisΦ ì
thi≤á iµá yo⌡á happeεá t∩ havσ thσ sparσ fli≡ flo≡á anΣá O╥á gatσ ì
floatinτá arounΣ oε you≥ board«á ╔ didn'⌠ anΣ simpl∙á redesigneΣ ì
thσ wait-statσ generato≥ t∩ accomplisΦ thσ samσ thing.
No≈ Modσ ▓ work≤ jus⌠ fine.
è
The following section is by:
KA8BMT
Reference:
HitachΘá HD6418░ 8-Bi⌠ HigΦ Integratioε CMO╙ Microprocesso≥á Datß ì
Booδ [January¼ 198╡ #U77]
PG 27: I/O ADDRESSING NOTES:
"Thσá on-chi≡ I/╧ registe≥ addresse≤ arσ locateΣ iε thσá I/╧ ì
addres≤á spacσ froφ 0000╚ t∩ 00FF╚ (16-bi⌠ I/╧á addresses).óá [┴ ì
notσá unde≥ figurσ 2.2.╡ oε pagσ 15║á 'NOTE║á A16-A1╕ ╜ ░ fo≥ I/╧ ì
cycles'.▌ "Thus¼á t∩ acces≤ thσ on-chi≡ I/╧ register≤ (usinτá I/╧ ì
instructions),"
[I≤ therσ somσ othe≥ wa∙ t∩ acces≤ thesσ registers¼á beside≤ ì
I/╧ instructions┐ IOE¬ anΣ ME¬ woulΣ determinσ whethe≥ i⌠ i≤ I/╧ ì
o≥á MEmory¼á s∩ wha⌠ doe≤ thσ las⌠ par⌠ oµ thσ previou≤ paragrapΦ ì
mean?]
"thσ high-orde≥ ╕ bit≤ oµ thσ 16-bi⌠ I/╧ addres≤ mus⌠ bσ 0."
"Thσá conventiona∞ I/╧ instruction≤ (OU╘ (m),┴ » I╬ A,(m⌐á » ì
OUT╔ » IN╔ » etc.⌐ Placσ thσ content≤ oµ ß CP╒ register,"
[Thσ "Bó register¼á thi≤ i≤ becausσ oµ thσ wa∙ thσ Z-8░ (tm⌐ ì
handle≤á thσ "I╬ g,(C)ó anΣ thσ "OU╘ (C),góá instructions«á Thi≤ ì
mean≤á tha⌠ yo⌡ coulΣ desigε ß Z-8░ circui⌠ tha⌠ coulΣ havσá morσ ì
thaεá 25╢ I/╧ address¼á b∙ usinτ thσ "Bó registe≥ a≤ par⌠ oµá thσ ì
I/╧á address«á Thi≤á coulΣ als∩ mean≤ tha⌠ iµ you≥á I/╧á addres≤ ì
decode≥ doe≤ no⌠ properl∙ accoun⌠ fo≥ thσ A╕ - A1╡ addres≤á line≤ ì
yo⌡ ma∙ no⌠ ge⌠ thσ I/╧ addres≤ yo⌡ want.]
"oεá thσá high-orde≥ ╕ bit≤ oµ thσ addres≤ bus¼á anΣ thu≤ ma∙á bσ ì
difficul⌠ t∩ usσ fo≥ accessinτ oε chi≡ I/╧ registers."
"Fo≥ efficien⌠ on-chi≡ I/╧ register≤ access¼ ß numbe≥ oµ ne≈ ì
instruction≤ havσ beeε addeΣ whicΦ forcσ thσ high-orde≥ ╕ bit≤ oµ ì
thσ 16-bi⌠ I/╧ addres≤ t∩ 0«á Thesσ instruction≤ arσ IN0¼á OUT0¼ ì
OTIM¼á OTIMR¼ OTDM¼ OTDM╥ anΣ TSTI╧ (Seσ sectioε 3.▒ Instruction≤ ì
set)."
[Unfortunitl∙áá thσá instruction≤á describeΣá iεá thσáá las⌠ ì
paragrapΦá woulΣá no⌠á bσ Z-8░ compatible¼á iµá tha⌠á i≤á oµá an∙ ì
consideration«á ┴á possiblσá solutioε woulΣ bσ t∩ zer∩á thσá "Bó ì
registe≥áá oµá thσá 6418░á o≥á thσá Z-8░á beforσá doinτá an∙á I/╧ ì
instructions¼á howeve≥á thi≤á ma∙á no⌠ bσ possiblσá {iµá thσá "Bó ì
registe≥ i≤ beinτ used² o≥ practica∞ iε al∞ cases.]
è
"Notσá tha⌠ wheε writinτ t∩ aε interna∞á I/╧á register¼á thσ ì
samσá I/╧á writσá occur≤á oεá thσá externa∞á bus«á However¼á thσ ì
duplicatσá externa∞á I/╧á writσ cyclσ wil∞ exhibi⌠á interna∞á I/╧ ì
writσá cyclσá timing«á Fo≥á example¼á thσ WAIT¬á inpu⌠á anΣá thσ ì
programmablσá wai⌠á statσ generato≥ arσá ignored.óá [Thi≤á coulΣ ì
conceivabl∙á causσá somσ slo≈ peripheral≤ t∩ 'g∩ ou⌠ t∩á lunch'.▌ ì
"Similarly¼á interna∞á I/╧á reaΣ cycle≤ als∩á causσá ßá duplicatσ ì
externa∞á I/╧á reaΣ cyclσ - however¼á thσ externa∞ reaΣá datßá i≤ ì
ignoreΣ b∙ thσ HD64180."
"Normally¼á externa∞ I/╧ addresse≤ shoulΣ bσ choseε t∩ avoiΣ ì
overla≡á witΦá interna∞á I/╧á addresse≤ t∩á avoiΣá duplicatσá I/╧ ì
accesses."
Severa∞ place≤ HitachΘ state≤ tha⌠ thσ HD6418░ caεá directl∙ ì
addres≤á 64╦ oµ I/╧ addres≤ [whicΦ i⌠ caε iε hardward▌ (page≤á 2¼ ì
5¼á 15¼á 5▒ anΣ others)¼ howeve≥ i⌠ doe≤ no⌠ tel∞ ho≈ t∩ d∩ i⌠ iε ì
software«á I≤ therσ somσ wa∙ beside≤ doinτ trick≤ witΦ "B"¼á DM┴ ì
o≥á I/╧ blocδ instructions¼á tha⌠ ╔ missed¼á t∩ addres≤ morσ thaε ì
25╢áá I/╧á locations┐áá (SucΦá a≤á "OU╘á (1234H),regóá o≥áá "I╬ ì
reg,(1234H)".)