home *** CD-ROM | disk | FTP | other *** search
/ BBS in a Box 5 / BBS in a Box -Volume V (BBS in a Box) (April 1992).iso / Files / Apple / Apple II TNs(Text).cpt / Apple II TNs(Text) / IIGS / TN.IIGS.039 < prev    next >
MacBinary  |  1989-11-15  |  6.9 KB  |  [TEXT/pdos]

open in: MacOS 8.1     |     Win98     |     DOS

view JSON data     |     view as text

This file was processed as: MacBinary (archive/macBinary).

You can browse this item here: TN.IIGS.039

ConfidenceProgramDetectionMatch TypeSupport
10% dexvert MacBinary (archive/macBinary) fallback Supported
1% dexvert Text File (text/txt) fallback Supported
100% file MacBinary II, inited, Wed Nov 15 12:34:52 1989, modified Wed Nov 15 12:34:52 1989, creator Apple ProDOS file system, type ASCII, 6449 bytes "TN.IIGS.039" , at 0x19b1 382 bytes resource default (weak)
99% file data default
74% TrID Macintosh plain text (MacBinary) default
25% TrID MacBinary 2 default (weak)
100% siegfried fmt/1762 MacBinary (II) default
100% lsar MacBinary default


id metadata
keyvalue
macFileType[TEXT]
macFileCreator[pdos]



hex view
+--------+-------------------------+-------------------------+--------+--------+
|00000000| 00 0b 54 4e 2e 49 49 47 | 53 2e 30 33 39 00 00 00 |..TN.IIG|S.039...|
|00000010| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|00000020| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|00000030| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|00000040| 00 54 45 58 54 70 64 6f | 73 01 00 00 00 00 00 00 |.TEXTpdo|s.......|
|00000050| 00 00 00 00 00 19 31 00 | 00 01 7e a1 87 4e bc a1 |......1.|..~..N..|
|00000060| 87 4e bc 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |.N......|........|
|00000070| 00 00 00 00 00 00 00 00 | 00 00 81 81 4a d1 00 00 |........|....J...|
|00000080| 41 70 70 6c 65 20 49 49 | 0d 54 65 63 68 6e 69 63 |Apple II|.Technic|
|00000090| 61 6c 20 4e 6f 74 65 73 | 0d 5f 5f 5f 5f 5f 5f 5f |al Notes|._______|
|000000a0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000000b0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000000c0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000000d0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000000e0| 5f 5f 5f 5f 5f 5f 0d 20 | 20 20 20 20 20 20 20 20 |______. | |
|000000f0| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|00000100| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|00000110| 20 20 20 20 20 20 20 20 | 20 44 65 76 65 6c 6f 70 | | Develop|
|00000120| 65 72 20 54 65 63 68 6e | 69 63 61 6c 20 53 75 70 |er Techn|ical Sup|
|00000130| 70 6f 72 74 0d 0d 0d 41 | 70 70 6c 65 20 49 49 47 |port...A|pple IIG|
|00000140| 53 0d 23 33 39 3a 20 20 | 20 20 4d 65 67 61 20 49 |S.#39: | Mega I|
|00000150| 49 20 56 69 64 65 6f 20 | 43 6f 75 6e 74 65 72 73 |I Video |Counters|
|00000160| 0d 0d 52 65 76 69 73 65 | 64 20 62 79 3a 20 20 20 |..Revise|d by: |
|00000170| 20 44 61 76 65 20 4c 79 | 6f 6e 73 20 20 20 20 20 | Dave Ly|ons |
|00000180| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|00000190| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|000001a0| 20 20 20 20 20 20 4a 75 | 6c 79 20 31 39 38 39 0d | Ju|ly 1989.|
|000001b0| 57 72 69 74 74 65 6e 20 | 62 79 3a 20 20 20 20 4a |Written |by: J|
|000001c0| 2e 20 52 69 63 6b 61 72 | 64 20 20 20 20 20 20 20 |. Rickar|d |
|000001d0| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|000001e0| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|000001f0| 20 20 20 20 20 4d 61 79 | 20 31 39 38 38 0d 0d 54 | May| 1988..T|
|00000200| 68 69 73 20 54 65 63 68 | 6e 69 63 61 6c 20 4e 6f |his Tech|nical No|
|00000210| 74 65 20 64 65 73 63 72 | 69 62 65 73 20 74 68 65 |te descr|ibes the|
|00000220| 20 4d 65 67 61 20 49 49 | 20 76 69 64 65 6f 20 6f | Mega II| video o|
|00000230| 75 74 70 75 74 20 72 65 | 67 69 73 74 65 72 73 2c |utput re|gisters,|
|00000240| 20 77 68 69 63 68 20 79 | 6f 75 72 20 0d 61 70 70 | which y|our .app|
|00000250| 6c 69 63 61 74 69 6f 6e | 73 20 63 61 6e 20 75 73 |lication|s can us|
|00000260| 65 20 74 6f 20 67 65 74 | 20 69 6e 66 6f 72 6d 61 |e to get| informa|
|00000270| 74 69 6f 6e 20 61 62 6f | 75 74 20 77 68 65 72 65 |tion abo|ut where|
|00000280| 20 74 68 65 20 62 65 61 | 6d 20 69 73 20 6c 6f 63 | the bea|m is loc|
|00000290| 61 74 65 64 20 6f 6e 20 | 74 68 65 20 0d 41 70 70 |ated on |the .App|
|000002a0| 6c 65 20 49 49 47 53 20 | 64 69 73 70 6c 61 79 2e |le IIGS |display.|
|000002b0| 0d 43 68 61 6e 67 65 73 | 20 73 69 6e 63 65 20 4e |.Changes| since N|
|000002c0| 6f 76 65 6d 62 65 72 20 | 31 39 38 38 3a 20 20 43 |ovember |1988: C|
|000002d0| 6f 72 72 65 63 74 65 64 | 20 64 65 73 63 72 69 70 |orrected| descrip|
|000002e0| 74 69 6f 6e 20 6f 66 20 | 77 68 65 6e 20 56 42 4c |tion of |when VBL|
|000002f0| 20 62 65 67 69 6e 73 20 | 0d 61 6e 64 20 73 69 6d | begins |.and sim|
|00000300| 70 6c 69 66 69 65 64 20 | 65 78 61 6d 70 6c 65 20 |plified |example |
|00000310| 63 6f 64 65 20 74 6f 20 | 72 65 61 64 20 74 68 65 |code to |read the|
|00000320| 20 73 63 61 6e 20 6c 69 | 6e 65 20 6e 75 6d 62 65 | scan li|ne numbe|
|00000330| 72 2e 0d 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |r.._____|________|
|00000340| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000350| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000360| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000370| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000380| 0d 0d 54 68 65 20 4d 65 | 67 61 20 49 49 20 63 6f |..The Me|ga II co|
|00000390| 6e 74 72 6f 6c 73 20 76 | 69 64 65 6f 20 74 69 6d |ntrols v|ideo tim|
|000003a0| 69 6e 67 20 66 6f 72 20 | 74 68 65 20 41 70 70 6c |ing for |the Appl|
|000003b0| 65 20 49 49 47 53 20 77 | 69 74 68 20 61 20 31 36 |e IIGS w|ith a 16|
|000003c0| 2d 62 69 74 20 63 6f 75 | 6e 74 65 72 20 0d 73 70 |-bit cou|nter .sp|
|000003d0| 6c 69 74 20 69 6e 74 6f | 20 61 20 37 2d 62 69 74 |lit into| a 7-bit|
|000003e0| 20 68 6f 72 69 7a 6f 6e | 74 61 6c 20 61 6e 64 20 | horizon|tal and |
|000003f0| 61 20 39 2d 62 69 74 20 | 76 65 72 74 69 63 61 6c |a 9-bit |vertical|
|00000400| 20 70 61 72 74 20 28 46 | 69 67 75 72 65 20 31 29 | part (F|igure 1)|
|00000410| 2e 20 20 54 68 65 20 0d | 63 6f 75 6e 74 65 72 20 |. The .|counter |
|00000420| 6f 75 74 70 75 74 73 20 | 61 72 65 20 6d 61 64 65 |outputs |are made|
|00000430| 20 61 76 61 69 6c 61 62 | 6c 65 20 74 6f 20 70 72 | availab|le to pr|
|00000440| 6f 67 72 61 6d 73 20 72 | 75 6e 6e 69 6e 67 20 6f |ograms r|unning o|
|00000450| 6e 20 74 68 65 20 6d 61 | 63 68 69 6e 65 20 74 68 |n the ma|chine th|
|00000460| 72 6f 75 67 68 20 0d 74 | 77 6f 20 61 64 64 72 65 |rough .t|wo addre|
|00000470| 73 73 65 73 20 69 6e 20 | 74 68 65 20 49 2f 4f 20 |sses in |the I/O |
|00000480| 73 70 61 63 65 2c 20 24 | 43 30 32 45 20 66 6f 72 |space, $|C02E for|
|00000490| 20 74 68 65 20 76 65 72 | 74 69 63 61 6c 20 63 6f | the ver|tical co|
|000004a0| 75 6e 74 20 61 6e 64 20 | 24 43 30 32 46 20 66 6f |unt and |$C02F fo|
|000004b0| 72 20 74 68 65 20 0d 68 | 6f 72 69 7a 6f 6e 74 61 |r the .h|orizonta|
|000004c0| 6c 20 63 6f 75 6e 74 2e | 20 20 54 68 65 73 65 20 |l count.| These |
|000004d0| 6f 75 74 70 75 74 73 20 | 63 61 6e 20 62 65 20 75 |outputs |can be u|
|000004e0| 73 65 64 20 62 79 20 61 | 20 70 72 6f 67 72 61 6d |sed by a| program|
|000004f0| 20 66 6f 72 20 66 69 6e | 65 72 20 63 6f 6e 74 72 | for fin|er contr|
|00000500| 6f 6c 20 0d 6f 76 65 72 | 20 64 69 73 70 6c 61 79 |ol .over| display|
|00000510| 20 75 70 64 61 74 65 20 | 74 69 6d 69 6e 67 2e 0d | update |timing..|
|00000520| 0d 20 20 20 20 20 20 5f | 5f 5f 5f 5f 5f 5f 5f 5f |. _|________|
|00000530| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000540| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000550| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000560| 5f 5f 5f 5f 5f 5f 0d 20 | 20 20 20 20 7c 20 20 20 |______. | | |
|00000570| 20 20 20 20 20 20 20 56 | 65 72 74 69 63 61 6c 20 | V|ertical |
|00000580| 43 6f 75 6e 74 65 72 20 | 20 20 20 20 20 20 20 20 |Counter | |
|00000590| 7c 20 20 20 20 20 48 6f | 72 69 7a 6f 6e 74 61 6c || Ho|rizontal|
|000005a0| 20 43 6f 75 6e 74 65 72 | 20 20 20 20 7c 0d 20 20 | Counter| |. |
|000005b0| 20 20 20 7c 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f | |____|________|
|000005c0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000005d0| 5f 5f 5f 5f 5f 5f 5f 7c | 5f 5f 5f 5f 5f 5f 5f 5f |_______||________|
|000005e0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000005f0| 5f 5f 5f 7c 0d 20 20 20 | 20 20 7c 20 56 35 7c 20 |___|. | | V5| |
|00000600| 56 34 7c 20 56 33 7c 20 | 56 32 7c 20 56 31 7c 20 |V4| V3| |V2| V1| |
|00000610| 56 30 7c 20 56 43 7c 20 | 56 42 7c 20 56 41 7c 48 |V0| VC| |VB| VA|H|
|00000620| 50 45 7c 20 48 35 7c 20 | 48 34 7c 20 48 33 7c 20 |PE| H5| |H4| H3| |
|00000630| 48 32 7c 20 48 31 7c 20 | 48 30 7c 0d 20 20 20 20 |H2| H1| |H0|. |
|00000640| 20 7c 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f | |______|________|
|00000650| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000660| 5f 7c 5f 5f 5f 7c 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |_|___|__|________|
|00000670| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000680| 5f 7c 0d 20 20 20 20 20 | 7c 20 20 20 20 20 20 20 |_|. || |
|00000690| 20 20 20 20 20 24 45 30 | 43 30 32 45 20 20 20 20 | $E0|C02E |
|000006a0| 20 20 20 20 20 20 20 20 | 7c 20 20 20 20 20 20 20 | || |
|000006b0| 20 20 20 20 20 20 24 45 | 30 43 30 32 46 20 20 20 | $E|0C02F |
|000006c0| 20 20 20 20 20 20 20 20 | 7c 0d 20 20 20 20 20 7c | ||. ||
|000006d0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000006e0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|000006f0| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00000700| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 7c |________|_______||
|00000710| 0d 0d 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 |.. | |
|00000720| 20 20 20 20 20 20 20 20 | 20 46 69 67 75 72 65 20 | | Figure |
|00000730| 31 20 2d 20 4d 65 67 61 | 20 49 49 20 56 69 64 65 |1 - Mega| II Vide|
|00000740| 6f 20 43 6f 75 6e 74 65 | 72 0d 0d 59 6f 75 20 63 |o Counte|r..You c|
|00000750| 61 6e 20 73 65 65 20 74 | 68 61 74 20 6f 6e 65 20 |an see t|hat one |
|00000760| 62 69 74 20 6f 66 20 74 | 68 65 20 6e 69 6e 65 2d |bit of t|he nine-|
|00000770| 62 69 74 20 76 65 72 74 | 69 63 61 6c 20 63 6f 75 |bit vert|ical cou|
|00000780| 6e 74 65 72 20 69 73 20 | 69 6e 20 6c 6f 63 61 74 |nter is |in locat|
|00000790| 69 6f 6e 20 0d 24 45 30 | 43 30 32 46 20 77 69 74 |ion .$E0|C02F wit|
|000007a0| 68 20 74 68 65 20 73 65 | 76 65 6e 20 62 69 74 73 |h the se|ven bits|
|000007b0| 20 6f 66 20 74 68 65 20 | 68 6f 72 69 7a 6f 6e 74 | of the |horizont|
|000007c0| 61 6c 20 63 6f 75 6e 74 | 65 72 2e 20 20 4b 65 65 |al count|er. Kee|
|000007d0| 70 20 74 68 69 73 20 6c | 6f 63 61 74 69 6f 6e 20 |p this l|ocation |
|000007e0| 69 6e 20 0d 6d 69 6e 64 | 20 77 68 65 6e 20 72 65 |in .mind| when re|
|000007f0| 61 64 69 6e 67 20 74 68 | 65 20 63 6f 75 6e 74 65 |ading th|e counte|
|00000800| 72 73 2e 0d 0d 54 68 65 | 20 73 65 76 65 6e 2d 62 |rs...The| seven-b|
|00000810| 69 74 20 68 6f 72 69 7a | 6f 6e 74 61 6c 20 63 6f |it horiz|ontal co|
|00000820| 75 6e 74 65 72 20 73 74 | 61 72 74 73 20 61 74 20 |unter st|arts at |
|00000830| 24 30 30 20 61 6e 64 20 | 63 6f 75 6e 74 73 20 66 |$00 and |counts f|
|00000840| 72 6f 6d 20 24 34 30 20 | 74 6f 20 24 37 46 20 28 |rom $40 |to $7F (|
|00000850| 74 68 65 20 0d 73 65 71 | 75 65 6e 63 65 20 69 73 |the .seq|uence is|
|00000860| 20 24 30 30 2c 20 24 34 | 30 2c 20 24 34 31 2c 2e | $00, $4|0, $41,.|
|00000870| 2e 2e 2c 24 37 45 2c 20 | 24 37 46 2c 20 24 30 30 |..,$7E, |$7F, $00|
|00000880| 2c 20 24 34 30 2c 2e 2e | 2e 29 2e 20 20 54 68 65 |, $40,..|.). The|
|00000890| 20 61 63 74 69 76 65 20 | 76 69 64 65 6f 20 74 69 | active |video ti|
|000008a0| 6d 65 20 0d 63 6f 6e 73 | 69 73 74 73 20 6f 66 20 |me .cons|ists of |
|000008b0| 34 30 20 6f 6e 65 20 6d | 69 63 72 6f 73 65 63 6f |40 one m|icroseco|
|000008c0| 6e 64 20 63 6c 6f 63 6b | 20 63 79 63 6c 65 73 20 |nd clock| cycles |
|000008d0| 73 74 61 72 74 69 6e 67 | 20 77 69 74 68 20 24 35 |starting| with $5|
|000008e0| 38 20 61 6e 64 20 65 6e | 64 69 6e 67 0d 77 69 74 |8 and en|ding.wit|
|000008f0| 68 20 24 37 46 2e 20 20 | 53 69 6e 63 65 20 74 68 |h $7F. |Since th|
|00000900| 69 73 20 63 6f 75 6e 74 | 20 63 68 61 6e 67 65 73 |is count| changes|
|00000910| 20 61 74 20 39 38 30 20 | 6e 61 6e 6f 73 65 63 6f | at 980 |nanoseco|
|00000920| 6e 64 20 69 6e 74 65 72 | 76 61 6c 73 2c 20 69 74 |nd inter|vals, it|
|00000930| 20 77 69 6c 6c 0d 70 72 | 6f 62 61 62 6c 79 20 62 | will.pr|obably b|
|00000940| 65 20 6f 66 20 6c 69 74 | 74 6c 65 20 75 73 65 20 |e of lit|tle use |
|00000950| 74 6f 20 6d 6f 73 74 20 | 70 72 6f 67 72 61 6d 73 |to most |programs|
|00000960| 2e 0d 0d 54 68 65 20 6e | 69 6e 65 2d 62 69 74 20 |...The n|ine-bit |
|00000970| 76 65 72 74 69 63 61 6c | 20 63 6f 75 6e 74 65 72 |vertical| counter|
|00000980| 20 72 61 6e 67 65 73 20 | 66 72 6f 6d 20 24 46 41 | ranges |from $FA|
|00000990| 20 74 68 72 6f 75 67 68 | 20 24 31 46 46 20 28 32 | through| $1FF (2|
|000009a0| 35 30 20 74 68 72 6f 75 | 67 68 20 35 31 31 29 20 |50 throu|gh 511) |
|000009b0| 0d 69 6e 20 4e 54 53 43 | 20 6d 6f 64 65 20 28 76 |.in NTSC| mode (v|
|000009c0| 65 72 74 69 63 61 6c 20 | 6c 69 6e 65 20 63 6f 75 |ertical |line cou|
|000009d0| 6e 74 20 6f 66 20 32 36 | 32 29 20 61 6e 64 20 66 |nt of 26|2) and f|
|000009e0| 72 6f 6d 20 24 43 38 20 | 74 68 72 6f 75 67 68 20 |rom $C8 |through |
|000009f0| 24 31 46 46 20 28 32 30 | 30 20 0d 74 68 72 6f 75 |$1FF (20|0 .throu|
|00000a00| 67 68 20 35 31 31 29 20 | 69 6e 20 50 41 4c 20 76 |gh 511) |in PAL v|
|00000a10| 69 64 65 6f 20 74 69 6d | 69 6e 67 20 6d 6f 64 65 |ideo tim|ing mode|
|00000a20| 20 28 76 65 72 74 69 63 | 61 6c 20 6c 69 6e 65 20 | (vertic|al line |
|00000a30| 63 6f 75 6e 74 20 6f 66 | 20 33 31 32 29 2e 20 20 |count of| 312). |
|00000a40| 56 65 72 74 69 63 61 6c | 20 0d 63 6f 75 6e 74 65 |Vertical| .counte|
|00000a50| 72 20 76 61 6c 75 65 20 | 24 31 30 30 20 63 6f 72 |r value |$100 cor|
|00000a60| 72 65 73 70 6f 6e 64 73 | 20 74 6f 20 73 63 61 6e |responds| to scan|
|00000a70| 20 6c 69 6e 65 20 7a 65 | 72 6f 20 69 6e 20 4e 54 | line ze|ro in NT|
|00000a80| 53 43 20 6d 6f 64 65 2e | 20 20 54 68 65 20 76 65 |SC mode.| The ve|
|00000a90| 72 74 69 63 61 6c 20 0d | 63 6f 75 6e 74 20 63 68 |rtical .|count ch|
|00000aa0| 61 6e 67 65 73 20 61 74 | 20 36 33 2e 37 20 6d 69 |anges at| 63.7 mi|
|00000ab0| 63 72 6f 73 65 63 6f 6e | 64 20 69 6e 74 65 72 76 |crosecon|d interv|
|00000ac0| 61 6c 73 2c 20 67 69 76 | 69 6e 67 20 61 20 70 72 |als, giv|ing a pr|
|00000ad0| 6f 67 72 61 6d 20 74 69 | 6d 65 20 74 6f 20 72 65 |ogram ti|me to re|
|00000ae0| 73 70 6f 6e 64 0d 74 6f | 20 61 20 73 70 65 63 69 |spond.to| a speci|
|00000af0| 66 69 63 20 63 6f 75 6e | 74 20 62 65 66 6f 72 65 |fic coun|t before|
|00000b00| 20 69 74 20 63 68 61 6e | 67 65 73 2e 20 20 54 68 | it chan|ges. Th|
|00000b10| 65 20 76 65 72 74 69 63 | 61 6c 20 63 6f 75 6e 74 |e vertic|al count|
|00000b20| 65 72 20 62 79 74 65 2c | 20 61 74 20 24 45 30 43 |er byte,| at $E0C|
|00000b30| 30 32 45 2c 20 0d 6f 6e | 6c 79 20 63 68 61 6e 67 |02E, .on|ly chang|
|00000b40| 65 73 20 68 61 6c 66 20 | 61 73 20 6f 66 74 65 6e |es half |as often|
|00000b50| 20 28 61 74 20 31 32 37 | 20 6d 69 63 72 6f 73 65 | (at 127| microse|
|00000b60| 63 6f 6e 64 20 69 6e 74 | 65 72 76 61 6c 73 29 20 |cond int|ervals) |
|00000b70| 73 69 6e 63 65 20 74 68 | 65 20 6c 6f 77 65 73 74 |since th|e lowest|
|00000b80| 20 62 69 74 0d 6f 66 20 | 74 68 65 20 6e 69 6e 65 | bit.of |the nine|
|00000b90| 2d 62 69 74 20 63 6f 75 | 6e 74 65 72 20 69 73 20 |-bit cou|nter is |
|00000ba0| 61 63 74 75 61 6c 6c 79 | 20 73 74 6f 72 65 64 20 |actually| stored |
|00000bb0| 69 6e 20 74 68 65 20 6e | 65 78 74 20 62 79 74 65 |in the n|ext byte|
|00000bc0| 20 28 61 74 20 24 45 30 | 43 30 32 46 29 2e 0d 0d | (at $E0|C02F)...|
|00000bd0| 54 68 65 20 6e 69 6e 65 | 2d 62 69 74 20 63 6f 75 |The nine|-bit cou|
|00000be0| 6e 74 65 72 20 63 6f 6e | 73 69 73 74 73 20 6f 66 |nter con|sists of|
|00000bf0| 20 62 69 74 73 20 56 41 | 2c 20 56 42 2c 20 56 43 | bits VA|, VB, VC|
|00000c00| 2c 20 56 30 2c 20 56 31 | 2c 20 56 32 2c 20 56 33 |, V0, V1|, V2, V3|
|00000c10| 2c 20 56 34 20 61 6e 64 | 20 56 35 2e 20 20 0d 42 |, V4 and| V5. .B|
|00000c20| 69 74 73 20 56 30 20 74 | 68 72 6f 75 67 68 20 56 |its V0 t|hrough V|
|00000c30| 35 20 63 61 6e 20 62 65 | 20 72 65 61 64 20 61 73 |5 can be| read as|
|00000c40| 20 61 20 73 69 78 2d 62 | 69 74 20 76 61 6c 75 65 | a six-b|it value|
|00000c50| 2e 20 20 49 66 20 74 68 | 69 73 20 76 61 6c 75 65 |. If th|is value|
|00000c60| 20 69 73 20 62 65 74 77 | 65 65 6e 20 30 20 0d 61 | is betw|een 0 .a|
|00000c70| 6e 64 20 32 33 2c 20 69 | 74 20 69 73 20 74 68 65 |nd 23, i|t is the|
|00000c80| 20 6c 69 6e 65 20 6f 6e | 20 74 68 65 20 74 65 78 | line on| the tex|
|00000c90| 74 20 73 63 72 65 65 6e | 20 63 75 72 72 65 6e 74 |t screen| current|
|00000ca0| 6c 79 20 62 65 69 6e 67 | 20 75 70 64 61 74 65 64 |ly being| updated|
|00000cb0| 2e 20 20 4f 74 68 65 72 | 20 0d 76 61 6c 75 65 73 |. Other| .values|
|00000cc0| 20 69 6e 64 69 63 61 74 | 65 20 74 68 65 20 76 65 | indicat|e the ve|
|00000cd0| 72 74 69 63 61 6c 20 62 | 6c 61 6e 6b 69 6e 67 20 |rtical b|lanking |
|00000ce0| 63 79 63 6c 65 20 69 73 | 20 6f 63 63 75 72 72 69 |cycle is| occurri|
|00000cf0| 6e 67 2e 20 20 42 69 74 | 73 20 56 41 20 74 68 72 |ng. Bit|s VA thr|
|00000d00| 6f 75 67 68 20 56 43 20 | 0d 63 61 6e 20 62 65 20 |ough VC |.can be |
|00000d10| 72 65 61 64 20 61 73 20 | 61 20 74 68 72 65 65 2d |read as |a three-|
|00000d20| 62 69 74 20 76 61 6c 75 | 65 20 28 30 2d 37 29 20 |bit valu|e (0-7) |
|00000d30| 69 6e 64 69 63 61 74 69 | 6e 67 20 77 68 69 63 68 |indicati|ng which|
|00000d40| 20 73 63 61 6e 20 6c 69 | 6e 65 20 6f 66 20 61 20 | scan li|ne of a |
|00000d50| 74 65 78 74 20 0d 63 68 | 61 72 61 63 74 65 72 20 |text .ch|aracter |
|00000d60| 28 63 68 61 72 61 63 74 | 65 72 73 20 61 72 65 20 |(charact|ers are |
|00000d70| 63 6f 6d 70 6f 73 65 64 | 20 6f 66 20 65 69 67 68 |composed| of eigh|
|00000d80| 74 20 6c 69 6e 65 73 29 | 20 69 73 20 63 75 72 72 |t lines)| is curr|
|00000d90| 65 6e 74 6c 79 20 62 65 | 69 6e 67 20 64 72 61 77 |ently be|ing draw|
|00000da0| 6e 2e 0d 0d 54 68 65 20 | 76 65 72 74 69 63 61 6c |n...The |vertical|
|00000db0| 20 63 6f 75 6e 74 65 72 | 20 63 61 6e 20 61 6c 73 | counter| can als|
|00000dc0| 6f 20 62 65 20 75 73 65 | 64 20 74 6f 20 64 65 74 |o be use|d to det|
|00000dd0| 65 72 6d 69 6e 65 20 77 | 68 69 63 68 20 73 63 61 |ermine w|hich sca|
|00000de0| 6e 20 6c 69 6e 65 20 28 | 30 2d 31 39 31 20 66 6f |n line (|0-191 fo|
|00000df0| 72 20 0d 6d 6f 73 74 20 | 76 69 64 65 6f 20 6d 6f |r .most |video mo|
|00000e00| 64 65 73 2c 20 69 6e 63 | 6c 75 64 69 6e 67 20 68 |des, inc|luding h|
|00000e10| 69 67 68 2d 72 65 73 6f | 6c 75 74 69 6f 6e 20 61 |igh-reso|lution a|
|00000e20| 6e 64 20 64 6f 75 62 6c | 65 20 68 69 67 68 2d 72 |nd doubl|e high-r|
|00000e30| 65 73 6f 6c 75 74 69 6f | 6e 2c 20 61 6e 64 0d 30 |esolutio|n, and.0|
|00000e40| 2d 31 39 39 20 66 6f 72 | 20 73 75 70 65 72 20 68 |-199 for| super h|
|00000e50| 69 67 68 2d 72 65 73 6f | 6c 75 74 69 6f 6e 29 20 |igh-reso|lution) |
|00000e60| 69 73 20 62 65 69 6e 67 | 20 75 70 64 61 74 65 64 |is being| updated|
|00000e70| 20 61 74 20 61 6e 79 20 | 67 69 76 65 6e 20 6d 6f | at any |given mo|
|00000e80| 6d 65 6e 74 2e 0d 0d 45 | 78 61 6d 70 6c 65 0d 0d |ment...E|xample..|
|00000e90| 53 75 70 70 6f 73 65 20 | 79 6f 75 20 77 61 6e 74 |Suppose |you want|
|00000ea0| 20 74 6f 20 72 65 70 61 | 69 6e 74 20 61 20 70 6f | to repa|int a po|
|00000eb0| 72 74 69 6f 6e 20 6f 66 | 20 74 68 65 20 73 75 70 |rtion of| the sup|
|00000ec0| 65 72 20 68 69 67 68 2d | 72 65 73 6f 6c 75 74 69 |er high-|resoluti|
|00000ed0| 6f 6e 20 73 63 72 65 65 | 6e 20 74 68 61 74 20 0d |on scree|n that .|
|00000ee0| 77 69 6c 6c 20 72 65 71 | 75 69 72 65 20 6d 6f 72 |will req|uire mor|
|00000ef0| 65 20 74 69 6d 65 20 74 | 68 61 6e 20 74 68 65 20 |e time t|han the |
|00000f00| 76 65 72 74 69 63 61 6c | 20 62 6c 61 6e 6b 69 6e |vertical| blankin|
|00000f10| 67 20 70 65 72 69 6f 64 | 20 61 6c 6c 6f 77 73 2e |g period| allows.|
|00000f20| 20 20 59 6f 75 20 77 69 | 6c 6c 20 0d 68 61 76 65 | You wi|ll .have|
|00000f30| 20 61 20 74 65 61 72 20 | 69 6e 20 79 6f 75 72 20 | a tear |in your |
|00000f40| 61 6e 69 6d 61 74 69 6f | 6e 20 77 68 65 6e 20 74 |animatio|n when t|
|00000f50| 68 65 20 73 63 72 65 65 | 6e 27 73 20 72 65 66 72 |he scree|n's refr|
|00000f60| 65 73 68 20 63 79 63 6c | 65 20 63 61 74 63 68 65 |esh cycl|e catche|
|00000f70| 73 20 75 70 20 77 69 74 | 68 20 0d 79 6f 75 72 20 |s up wit|h .your |
|00000f80| 64 72 61 77 69 6e 67 2e | 0d 0d 4f 6e 65 20 73 6f |drawing.|..One so|
|00000f90| 6c 75 74 69 6f 6e 20 74 | 6f 20 74 68 69 73 20 70 |lution t|o this p|
|00000fa0| 72 6f 62 6c 65 6d 20 77 | 6f 75 6c 64 20 62 65 20 |roblem w|ould be |
|00000fb0| 6c 6f 63 61 74 69 6e 67 | 20 74 68 65 20 61 70 70 |locating| the app|
|00000fc0| 72 6f 78 69 6d 61 74 65 | 20 70 6c 61 63 65 20 74 |roximate| place t|
|00000fd0| 68 65 20 74 65 61 72 20 | 0d 6f 63 63 75 72 73 20 |he tear |.occurs |
|00000fe0| 61 6e 64 20 73 74 61 72 | 74 69 6e 67 20 79 6f 75 |and star|ting you|
|00000ff0| 72 20 64 72 61 77 69 6e | 67 20 77 68 65 6e 20 74 |r drawin|g when t|
|00001000| 68 65 20 73 79 73 74 65 | 6d 20 69 73 20 73 63 61 |he syste|m is sca|
|00001010| 6e 6e 69 6e 67 20 74 68 | 61 74 20 6c 69 6e 65 20 |nning th|at line |
|00001020| 6f 66 20 0d 67 72 61 70 | 68 69 63 73 2e 20 20 4c |of .grap|hics. L|
|00001030| 65 74 27 73 20 73 61 79 | 20 79 6f 75 20 61 72 65 |et's say| you are|
|00001040| 20 70 61 69 6e 74 69 6e | 67 20 61 6e 20 61 72 65 | paintin|g an are|
|00001050| 61 20 74 68 61 74 20 69 | 73 20 61 62 6f 75 74 20 |a that i|s about |
|00001060| 28 66 6f 72 20 65 78 61 | 6d 70 6c 65 29 20 31 30 |(for exa|mple) 10|
|00001070| 30 20 0d 70 69 78 65 6c | 73 20 77 69 64 65 20 61 |0 .pixel|s wide a|
|00001080| 6e 64 20 32 30 30 20 70 | 69 78 65 6c 73 20 74 61 |nd 200 p|ixels ta|
|00001090| 6c 6c 20 69 6e 20 33 32 | 30 20 6d 6f 64 65 2c 20 |ll in 32|0 mode, |
|000010a0| 61 6e 64 20 74 68 61 74 | 20 74 68 65 20 74 65 61 |and that| the tea|
|000010b0| 72 20 77 69 6c 6c 20 6f | 63 63 75 72 20 0d 73 6f |r will o|ccur .so|
|000010c0| 6d 65 77 68 65 72 65 20 | 61 72 6f 75 6e 64 20 73 |mewhere |around s|
|000010d0| 63 61 6e 20 6c 69 6e 65 | 20 38 30 2e 20 20 54 6f |can line| 80. To|
|000010e0| 20 61 76 6f 69 64 20 74 | 68 65 20 74 65 61 72 2c | avoid t|he tear,|
|000010f0| 20 79 6f 75 20 77 6f 75 | 6c 64 20 77 61 69 74 20 | you wou|ld wait |
|00001100| 75 6e 74 69 6c 20 74 68 | 65 20 0d 73 79 73 74 65 |until th|e .syste|
|00001110| 6d 20 69 73 20 73 63 61 | 6e 6e 69 6e 67 20 6c 69 |m is sca|nning li|
|00001120| 6e 65 20 38 30 2c 20 74 | 68 65 6e 20 79 6f 75 20 |ne 80, t|hen you |
|00001130| 77 6f 75 6c 64 20 73 74 | 61 72 74 20 72 65 64 72 |would st|art redr|
|00001140| 61 77 69 6e 67 20 61 74 | 20 74 68 65 20 74 6f 70 |awing at| the top|
|00001150| 20 6f 66 20 74 68 65 20 | 0d 73 63 72 65 65 6e 2e | of the |.screen.|
|00001160| 20 20 54 68 69 73 20 77 | 61 79 2c 20 79 6f 75 20 | This w|ay, you |
|00001170| 73 68 6f 75 6c 64 20 62 | 65 20 66 69 6e 69 73 68 |should b|e finish|
|00001180| 65 64 20 64 72 61 77 69 | 6e 67 20 77 68 65 6e 20 |ed drawi|ng when |
|00001190| 74 68 65 20 73 79 73 74 | 65 6d 20 69 73 20 62 61 |the syst|em is ba|
|000011a0| 63 6b 20 74 6f 20 0d 73 | 63 61 6e 6e 69 6e 67 20 |ck to .s|canning |
|000011b0| 6c 69 6e 65 20 38 30 20 | 61 67 61 69 6e 20 61 6e |line 80 |again an|
|000011c0| 64 20 79 6f 75 20 77 69 | 6c 6c 20 68 61 76 65 20 |d you wi|ll have |
|000011d0| 66 6c 69 63 6b 65 72 2d | 66 72 65 65 20 73 63 72 |flicker-|free scr|
|000011e0| 65 65 6e 20 75 70 64 61 | 74 69 6e 67 2e 0d 0d 54 |een upda|ting...T|
|000011f0| 68 65 20 74 72 69 63 6b | 79 20 70 61 72 74 20 69 |he trick|y part i|
|00001200| 73 20 74 72 79 69 6e 67 | 20 74 6f 20 64 65 74 65 |s trying| to dete|
|00001210| 72 6d 69 6e 65 20 6a 75 | 73 74 20 77 68 65 6e 20 |rmine ju|st when |
|00001220| 74 68 65 20 73 79 73 74 | 65 6d 20 69 73 20 73 63 |the syst|em is sc|
|00001230| 61 6e 6e 69 6e 67 20 61 | 6e 79 20 0d 67 69 76 65 |anning a|ny .give|
|00001240| 6e 20 73 63 61 6e 20 6c | 69 6e 65 2e 20 20 4f 6e |n scan l|ine. On|
|00001250| 65 20 77 61 79 20 74 6f | 20 64 65 74 65 72 6d 69 |e way to| determi|
|00001260| 6e 65 20 74 68 69 73 20 | 69 73 20 74 6f 20 65 78 |ne this |is to ex|
|00001270| 61 6d 69 6e 65 20 74 68 | 65 20 4d 65 67 61 20 49 |amine th|e Mega I|
|00001280| 49 20 76 69 64 65 6f 20 | 0d 63 6f 75 6e 74 65 72 |I video |.counter|
|00001290| 20 72 65 67 69 73 74 65 | 72 73 20 61 74 20 24 45 | registe|rs at $E|
|000012a0| 30 43 30 32 45 20 28 76 | 65 72 74 69 63 61 6c 29 |0C02E (v|ertical)|
|000012b0| 20 61 6e 64 20 24 45 30 | 43 30 32 46 20 28 68 6f | and $E0|C02F (ho|
|000012c0| 72 69 7a 6f 6e 74 61 6c | 29 2c 20 64 65 73 63 72 |rizontal|), descr|
|000012d0| 69 62 65 64 20 0d 61 62 | 6f 76 65 2e 20 20 42 79 |ibed .ab|ove. By|
|000012e0| 20 75 73 69 6e 67 20 73 | 6f 6d 65 20 73 69 6d 70 | using s|ome simp|
|000012f0| 6c 65 20 61 72 69 74 68 | 6d 65 74 69 63 20 79 6f |le arith|metic yo|
|00001300| 75 20 63 61 6e 20 63 6f | 6d 65 20 75 70 20 77 69 |u can co|me up wi|
|00001310| 74 68 20 74 68 65 20 65 | 78 61 63 74 20 73 63 61 |th the e|xact sca|
|00001320| 6e 20 0d 6c 69 6e 65 20 | 62 65 69 6e 67 20 75 70 |n .line |being up|
|00001330| 64 61 74 65 64 2e 20 20 | 54 68 65 20 66 6f 6c 6c |dated. |The foll|
|00001340| 6f 77 69 6e 67 20 70 69 | 65 63 65 20 6f 66 20 63 |owing pi|ece of c|
|00001350| 6f 64 65 20 63 6f 6d 70 | 75 74 65 73 20 74 68 65 |ode comp|utes the|
|00001360| 20 63 75 72 72 65 6e 74 | 20 73 63 61 6e 20 0d 6c | current| scan .l|
|00001370| 69 6e 65 20 6e 75 6d 62 | 65 72 20 28 61 73 73 75 |ine numb|er (assu|
|00001380| 6d 69 6e 67 20 65 69 67 | 68 74 2d 62 69 74 20 6e |ming eig|ht-bit n|
|00001390| 61 74 69 76 65 20 6d 6f | 64 65 29 3a 0d 0d 20 20 |ative mo|de):.. |
|000013a0| 20 20 6c 64 61 20 20 20 | 20 3e 24 45 30 43 30 32 | lda | >$E0C02|
|000013b0| 46 0d 20 20 20 20 61 73 | 6c 20 20 20 20 41 20 20 |F. as|l A |
|000013c0| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|000013d0| 20 20 3b 56 41 20 69 73 | 20 6e 6f 77 20 69 6e 20 | ;VA is| now in |
|000013e0| 74 68 65 20 43 61 72 72 | 79 20 66 6c 61 67 0d 20 |the Carr|y flag. |
|000013f0| 20 20 20 6c 64 61 20 20 | 20 20 3e 24 45 30 43 30 | lda | >$E0C0|
|00001400| 32 45 0d 20 20 20 20 72 | 6f 6c 20 20 20 20 41 20 |2E. r|ol A |
|00001410| 20 20 20 20 20 20 20 20 | 20 20 20 20 20 20 20 20 | | |
|00001420| 20 20 20 3b 72 6f 6c 6c | 20 43 61 72 72 79 20 69 | ;roll| Carry i|
|00001430| 6e 74 6f 20 62 69 74 20 | 30 0d 0d 54 68 65 20 72 |nto bit |0..The r|
|00001440| 65 73 75 6c 74 20 28 69 | 6e 20 41 29 20 69 73 20 |esult (i|n A) is |
|00001450| 74 68 65 20 6c 6f 77 20 | 62 79 74 65 20 6f 66 20 |the low |byte of |
|00001460| 74 68 65 20 76 65 72 74 | 69 63 61 6c 20 63 6f 75 |the vert|ical cou|
|00001470| 6e 74 65 72 2e 20 20 54 | 68 69 73 20 76 61 6c 75 |nter. T|his valu|
|00001480| 65 20 69 73 20 30 20 0d | 66 6f 72 20 74 68 65 20 |e is 0 .|for the |
|00001490| 66 69 72 73 74 20 73 63 | 61 6e 20 6c 69 6e 65 2c |first sc|an line,|
|000014a0| 20 31 20 66 6f 72 20 74 | 68 65 20 73 65 63 6f 6e | 1 for t|he secon|
|000014b0| 64 20 73 63 61 6e 20 6c | 69 6e 65 2c 20 65 74 63 |d scan l|ine, etc|
|000014c0| 2e 20 20 56 61 6c 75 65 | 73 20 24 46 41 20 74 6f |. Value|s $FA to|
|000014d0| 20 24 46 46 20 0d 61 72 | 65 20 75 73 65 64 20 74 | $FF .ar|e used t|
|000014e0| 77 69 63 65 2c 20 73 69 | 6e 63 65 20 79 6f 75 20 |wice, si|nce you |
|000014f0| 69 67 6e 6f 72 65 20 74 | 68 65 20 68 69 67 68 20 |ignore t|he high |
|00001500| 62 79 74 65 20 6f 66 20 | 74 68 65 20 76 65 72 74 |byte of |the vert|
|00001510| 69 63 61 6c 20 63 6f 75 | 6e 74 65 72 2e 20 20 28 |ical cou|nter. (|
|00001520| 54 68 65 20 0d 73 69 78 | 20 73 63 61 6e 20 6c 69 |The .six| scan li|
|00001530| 6e 65 73 20 69 6d 6d 65 | 64 69 61 74 65 6c 79 20 |nes imme|diately |
|00001540| 61 62 6f 76 65 20 73 63 | 61 6e 20 6c 69 6e 65 20 |above sc|an line |
|00001550| 30 20 61 72 65 20 6e 75 | 6d 62 65 72 65 64 20 24 |0 are nu|mbered $|
|00001560| 30 46 41 20 74 6f 20 24 | 30 46 46 2c 20 61 6e 64 |0FA to $|0FF, and|
|00001570| 20 0d 74 68 65 20 73 69 | 78 20 61 62 6f 76 65 20 | .the si|x above |
|00001580| 74 68 6f 73 65 20 61 72 | 65 20 24 31 46 41 20 74 |those ar|e $1FA t|
|00001590| 6f 20 24 31 46 46 2e 29 | 20 20 54 68 65 20 65 78 |o $1FF.)| The ex|
|000015a0| 61 6d 70 6c 65 20 63 6f | 64 65 20 6c 65 61 76 65 |ample co|de leave|
|000015b0| 73 20 74 68 65 20 68 69 | 67 68 65 73 74 20 0d 62 |s the hi|ghest .b|
|000015c0| 69 74 20 6f 66 20 74 68 | 65 20 76 65 72 74 69 63 |it of th|e vertic|
|000015d0| 61 6c 20 63 6f 75 6e 74 | 65 72 20 69 6e 20 74 68 |al count|er in th|
|000015e0| 65 20 43 61 72 72 79 20 | 66 6c 61 67 2c 20 69 66 |e Carry |flag, if|
|000015f0| 20 79 6f 75 20 72 65 61 | 6c 6c 79 20 77 61 6e 74 | you rea|lly want|
|00001600| 20 69 74 2e 0d 0d 4e 6f | 74 65 20 74 68 61 74 20 | it...No|te that |
|00001610| 74 68 65 20 56 42 4c 20 | 69 6e 74 65 72 72 75 70 |the VBL |interrup|
|00001620| 74 73 20 61 6c 77 61 79 | 73 20 74 72 69 67 67 65 |ts alway|s trigge|
|00001630| 72 20 61 74 20 73 63 61 | 6e 20 6c 69 6e 65 20 31 |r at sca|n line 1|
|00001640| 39 32 2c 20 65 76 65 6e | 20 69 6e 20 53 75 70 65 |92, even| in Supe|
|00001650| 72 20 0d 48 69 2d 52 65 | 73 20 64 69 73 70 6c 61 |r .Hi-Re|s displa|
|00001660| 79 20 6d 6f 64 65 2c 20 | 61 6e 64 20 74 68 61 74 |y mode, |and that|
|00001670| 20 74 68 65 20 24 43 30 | 31 39 20 73 6f 66 74 20 | the $C0|19 soft |
|00001680| 73 77 69 74 63 68 20 69 | 6e 64 69 63 61 74 65 73 |switch i|ndicates|
|00001690| 20 76 65 72 74 69 63 61 | 6c 20 0d 62 6c 61 6e 6b | vertica|l .blank|
|000016a0| 69 6e 67 20 69 73 20 69 | 6e 20 65 66 66 65 63 74 |ing is i|n effect|
|000016b0| 20 73 74 61 72 74 69 6e | 67 20 61 74 20 73 63 61 | startin|g at sca|
|000016c0| 6e 20 6c 69 6e 65 20 31 | 39 32 2e 20 20 42 65 20 |n line 1|92. Be |
|000016d0| 63 61 72 65 66 75 6c 20 | 70 6f 6c 6c 69 6e 67 20 |careful |polling |
|000016e0| 66 6f 72 20 61 20 0d 73 | 70 65 63 69 66 69 63 20 |for a .s|pecific |
|000016f0| 73 63 61 6e 20 6c 69 6e | 65 20 6e 75 6d 62 65 72 |scan lin|e number|
|00001700| 2d 2d 69 66 20 69 6e 74 | 65 72 72 75 70 74 73 20 |--if int|errupts |
|00001710| 61 72 65 20 65 6e 61 62 | 6c 65 64 2c 20 69 74 20 |are enab|led, it |
|00001720| 69 73 20 63 6f 6e 63 65 | 69 76 61 62 6c 65 20 74 |is conce|ivable t|
|00001730| 68 61 74 20 0d 74 68 65 | 20 73 79 73 74 65 6d 20 |hat .the| system |
|00001740| 77 69 6c 6c 20 62 65 20 | 62 75 73 79 20 70 72 6f |will be |busy pro|
|00001750| 63 65 73 73 69 6e 67 20 | 61 6e 20 69 6e 74 65 72 |cessing |an inter|
|00001760| 72 75 70 74 20 65 76 65 | 72 79 20 74 69 6d 65 20 |rupt eve|ry time |
|00001770| 74 68 61 74 20 73 63 61 | 6e 20 6c 69 6e 65 20 69 |that sca|n line i|
|00001780| 73 20 0d 62 65 69 6e 67 | 20 73 63 61 6e 6e 65 64 |s .being| scanned|
|00001790| 2c 20 73 6f 20 79 6f 75 | 72 20 70 72 6f 67 72 61 |, so you|r progra|
|000017a0| 6d 20 77 69 6c 6c 20 68 | 61 6e 67 20 66 6f 72 65 |m will h|ang fore|
|000017b0| 76 65 72 20 77 61 69 74 | 69 6e 67 20 66 6f 72 20 |ver wait|ing for |
|000017c0| 69 74 2e 0d 0d 53 65 74 | 74 69 6e 67 20 61 20 73 |it...Set|ting a s|
|000017d0| 63 61 6e 20 6c 69 6e 65 | 20 69 6e 74 65 72 72 75 |can line| interru|
|000017e0| 70 74 20 69 73 20 61 6e | 6f 74 68 65 72 20 77 61 |pt is an|other wa|
|000017f0| 79 20 74 6f 20 64 65 74 | 65 72 6d 69 6e 65 20 77 |y to det|ermine w|
|00001800| 68 65 6e 20 61 20 70 61 | 72 74 69 63 75 6c 61 72 |hen a pa|rticular|
|00001810| 20 0d 73 75 70 65 72 20 | 68 69 67 68 2d 72 65 73 | .super |high-res|
|00001820| 6f 6c 75 74 69 6f 6e 20 | 73 63 61 6e 20 6c 69 6e |olution |scan lin|
|00001830| 65 20 69 73 20 62 65 69 | 6e 67 20 64 72 61 77 6e |e is bei|ng drawn|
|00001840| 2e 20 20 48 6f 77 65 76 | 65 72 2c 20 79 6f 75 20 |. Howev|er, you |
|00001850| 6d 75 73 74 20 62 65 20 | 63 61 72 65 66 75 6c 20 |must be |careful |
|00001860| 0d 69 6e 20 74 75 72 6e | 69 6e 67 20 73 63 61 6e |.in turn|ing scan|
|00001870| 20 6c 69 6e 65 20 69 6e | 74 65 72 72 75 70 74 73 | line in|terrupts|
|00001880| 20 6f 6e 20 61 6e 64 20 | 6f 66 66 20 73 6f 20 74 | on and |off so t|
|00001890| 68 61 74 20 79 6f 75 20 | 64 6f 20 6e 6f 74 20 69 |hat you |do not i|
|000018a0| 6e 74 65 72 66 65 72 65 | 20 77 69 74 68 20 0d 74 |nterfere| with .t|
|000018b0| 68 65 20 63 75 72 73 6f | 72 20 69 6e 20 51 75 69 |he curso|r in Qui|
|000018c0| 63 6b 44 72 61 77 20 49 | 49 20 28 77 68 69 63 68 |ckDraw I|I (which|
|000018d0| 20 75 73 65 73 20 73 63 | 61 6e 20 6c 69 6e 65 20 | uses sc|an line |
|000018e0| 69 6e 74 65 72 72 75 70 | 74 73 29 2e 0d 0d 0d 46 |interrup|ts)....F|
|000018f0| 75 72 74 68 65 72 20 52 | 65 66 65 72 65 6e 63 65 |urther R|eference|
|00001900| 0d 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |._______|________|
|00001910| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00001920| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00001930| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 5f 5f |________|________|
|00001940| 5f 5f 5f 5f 5f 5f 5f 5f | 5f 5f 5f 5f 5f 5f 0d 20 |________|______. |
|00001950| 20 20 20 6f 20 20 20 20 | 41 70 70 6c 65 20 49 49 | o |Apple II|
|00001960| 47 53 20 54 6f 6f 6c 62 | 6f 78 20 52 65 66 65 72 |GS Toolb|ox Refer|
|00001970| 65 6e 63 65 2c 20 56 6f | 6c 75 6d 65 20 32 0d 20 |ence, Vo|lume 2. |
|00001980| 20 20 20 6f 20 20 20 20 | 41 70 70 6c 65 20 49 49 | o |Apple II|
|00001990| 47 53 20 54 65 63 68 6e | 69 63 61 6c 20 4e 6f 74 |GS Techn|ical Not|
|000019a0| 65 20 23 34 30 2c 20 56 | 42 4c 20 53 69 67 6e 61 |e #40, V|BL Signa|
|000019b0| 6c 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |l.......|........|
|000019c0| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|000019d0| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|000019e0| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|000019f0| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|00001a00| 00 00 01 00 00 00 01 4c | 00 00 00 4c 00 00 00 32 |.......L|...L...2|
|00001a10| 72 74 68 65 72 20 52 65 | 66 65 72 65 6e 63 65 0d |rther Re|ference.|
|00001a20| a5 09 41 70 70 6c 65 20 | 49 49 47 53 20 54 6f 6f |..Apple |IIGS Too|
|00001a30| 18 31 2e 20 44 44 49 4e | 49 54 45 78 70 61 6e 64 |.1. DDIN|ITExpand|
|00001a40| 54 65 6d 70 46 69 6c 65 | 20 70 02 00 00 00 44 44 |TempFile| p....DD|
|00001a50| 00 00 44 44 54 4d 44 44 | 41 50 01 00 00 80 00 c0 |..DDTMDD|AP......|
|00001a60| 00 00 00 00 00 00 00 00 | 00 00 00 00 00 00 00 00 |........|........|
|00001a70| 00 00 a5 ca d0 e4 00 00 | 19 31 00 00 01 7e 27 49 |........|.1...~'I|
|00001a80| 00 4a 20 04 90 88 d0 ab | 00 5e 28 2b 00 12 d8 ab |.J .....|.^(+....|
|00001a90| 00 16 d7 c4 a0 2e 70 02 | 61 00 00 f8 27 44 00 4e |......p.|a...'D.N|
|00001aa0| 27 7a ff 0c 00 56 27 7a | ff 02 00 52 24 6b 00 46 |'z...V'z|...R$k.F|
|00001ab0| 4e 75 08 38 00 01 0b 22 | 66 22 20 7a fe ea 91 eb |Nu.8..."|f" z....|
|00001ac0| 00 2a a0 2d 20 78 01 30 | b1 f8 01 14 63 00 02 4c |.*.- x.0|....c..L|
|00001ad0| a0 63 20 2b 00 1e d0 ab | 00 22 61 04 70 00 4e 75 |.c +....|."a.p.Nu|
|00001ae0| 22 00 a0 62 b1 c1 64 0e | 59 4f a9 fa 4a 9f a0 62 |"..b..d.|YO..J..b|
|00001af0| b1 c1 65 00 02 26 20 01 | 72 00 4e 75 20 6b 00 4a |..e..& .|r.Nu k.J|
|00001b00| 00 00 00 48 00 09 4d 6f | 6e 61 63 6f 00 74 20 20 |...H..Mo|naco.t |
|00001b10| 20 20 4a 75 6c 79 20 31 | 39 38 39 0d 0d 0d 0d 20 | July 1|989.... |
|00001b20| 20 20 20 41 70 70 00 06 | 00 04 00 3c 00 24 01 dd | App..|...<.$..|
|00001b30| 02 3d 00 3c 00 24 01 dd | 02 3d a1 16 33 98 00 00 |.=.<.$..|.=..3...|
|00001b40| 00 00 00 00 00 00 00 00 | 00 00 01 00 00 00 01 00 |........|........|
|00001b50| 00 00 01 4c 00 00 00 4c | 00 00 00 32 00 5c 15 a4 |...L...L|...2.\..|
|00001b60| 09 8e 00 00 00 1c 00 32 | 00 00 4d 50 53 52 00 00 |.......2|..MPSR..|
|00001b70| 00 0a 03 ed ff ff 00 00 | 00 00 00 5d a8 50 00 00 |........|...].P..|
+--------+-------------------------+-------------------------+--------+--------+