dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
Specifications for the Atari 2600/7800
2600 7800
CPU: 6507 6502C (custom, NOT 65C02)
RAM: 128 Bytes, in VLSI 4K, high speed
ROM: 6K max 52K max
Cpu Clock: 1.19 MHz 1.79 MHz
Graphics Clock: 3.58 MHz 7.16 MHz
Slot Config: Rom access only Most CPU lines + video/audio
CPU Avail: less than 50% over 90%
Notes:
1. ROM specs are based on a non-bank select scheme.
2. Graphics Clock is the master clock used to drive the video chips.
Programming the 2600 in a nutshell.
The Atari 2600 consists of 3 important ICs: the CPU (6507),
the Television Interface Adapter (TIA or Stella), and the RIOT (6532).
The 7800 has a CPU (6502C or Sally) instaed of the 6507 and a GCC1702
(Maria) chip in addition to the Stella chip.
The CPU:
The 6507 CPU is a 6502 with 2 important exceptions: it only has
external address lines for 8K of memory and there are NO interrupt lines
connected. This is not as limiting as it seems if you examine some of
the games for the machine.
The Stella chip:
This chip makes all the video displays and sounds for the 2600 VCS.
It also has 6 registers which are used as A/D converters and for the trigger
buttons on the joysticks. The chip also controls the RDY line of the CPU
to initiate horizontal syncronization control. The chip is NOT a DMA chip.
The CPU must write each line of data into the chip registers AS it draws
the screen. This accounts for the low CPU availability. The Chip is addresed
through 44 write only registers, and 13 read only registers mapped to
the low end of page 0. For those familiar with the Atari 800, this chip
is about 1/2 of a TIA/Pokey in all respects. But, there is no ANTIC chip to
drive it; the CPU must do all the work that the ANTIC does in the 800.
The RIOT
This chip reads all the console switches (excluding power), the
joysticks, and other controllers. It also contains the only RAM in the
system and a general purpose timer. The RAM is mapped to the high end of both page 0 and page 1. This means that it acts as both page 0 fast access memory
and the 6502 stack. The timer and I/O ports are mapped to Page 2 and 3.
In order to produce a video display, a program must do the following:
1. Start the vertical blanking interval
2. Start the vertical sync interval immediately
there is time for about 80 instructions after this
3. End vertical sync
the game computations must be done now as there won't be time later
4. End vertical blanking
5. Set up each line of the video display as it is drawn
there is time for about 6 instructions to the video chip before
the current line starts being displayed. Atari recommends changing
the display every other line to gain processing time.
6. Loop back to step 1
The Cartridge:
A standard cartridge contains the equivalent of a 2716 or 2732/2532
with one notable exception: the chip select line is active high, not low.
The high order address line of the 6507 (A12) is used as the chip enable.
There was at least one company that used EPROMs with a 74LS04 inverter to
compensate for this.
The Pinouts:
Note: numbers indicate left to right numbering
Top Row Bottom Row
Slot 2716 CPU 2716 CPU
1 13 D3 1 A7
2 14 D4 2 A6
3 15 D5 3 A5
4 16 D6 4 A4
5 17 D7 5 A3
6 * A12 6 A2
7 19 A10 7 A1
8 NC A11 8 A0
9 22 A9 9 D0
10 23 A8 10 D1
11 24 +5V 11 D2
12 12 Shield Ground NC Ground
* to inverter and back to 18 for chip select
Major differences between 2600 and 7800 mode:
2600 mode is default in the 7800. If it finds 128 bytes at the high
end of memory to match its encryption scheme, it will enable 7800 mode. There is a small ROM inside the unit which displays the Atari pattern on screen as
it does this.
The 7800 mode is DMA driven, so the processor is free most of the time
to do other things, as the graphics chip runs 4 times faster than the CPU.
The 7800 cartridge slot includes 8 more lines: A13, A14, A15, R/W,
phase 2 clock, audio, video, and HALT (unique to Atari 6502).
The 2600 video has foreground/background, 2 player/missles, and one
ball. The 7800 can display as many objects as the DMA can read in one line.
The sound is exactly the same as it still uses the Stella chip
(except Ballblazer which has its own sound chip in the cartridge).
--
Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu
Western Michigan University
Computer Science Department Voice: (616) 387-5803
Kalamazoo, MI 49008dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
; Atari Combat Game ; suspected RAM addresses ; ; E0-E3 score pattern offsets ; DE-DF score pattern calculation temporaries ; A1-A2 scores ; D2 score conversion temporary ; ; 9B-9C sound pitch storage ; B5-BA lo-res indirect addresses ; DA hi-res patterns ; D6-D7 colors SEI CLD LDX #FF TXS LDX #5D JSR J15BD ; zero out $00 thru $A2 LDA #10 STA SWCHB+1 STA 88 JSR J11A3 MLOOP JSR NWSCR ; $1014 JSR J1157 JSR J1572 JSR J12DA JSR J1444 JSR J1214 JSR J12A9 JSR J11F2 JSR J1054 JMP MLOOP ; NWSCR INC 86 ; initial blanking and retrace start STA HMCLR LDA #02 STA WSYNC STA VBLANK STA WSYNC STA WSYNC STA WSYNC STA SYNC STA WSYNC STA WSYNC LDA #00 STA WSYNC STA SYNC LDA #2B STA TIM64T RTS ; J1054 LDA #20 STA B4 STA WSYNC STA HMOVE B105C LDA INTIM BNE B105C STA WSYNC STA CXCLR STA VBLANK TSX STX D3 ; Save stack pointer LDA #02 STA CTRLPF LDX DC B1070 STA WSYNC DEX BNE B1070 LDA DC CMP #0E BEQ B10CD LDX #05 LDA #00 STA DE STA DF J1083 STA WSYNC LDA DE STA PF1 LDY E2 LDA L15C5,Y AND #F0 STA DE LDY E0 LDA L15C5,Y AND #0F ORA DE STA DE LDA DF STA PF1 LDY E3 LDA L15C5,Y AND #F0 STA DF LDY E1 LDA L15C5,Y AND 87 STA WSYNC ORA DF STA DF LDA DE STA PF1 DEX BMI B10CD INC E0 INC E2 INC E1 INC E3 LDA DF STA PF1 JMP J1083 ; B10CD LDA #00 ; Inner Display Loop STA PF1 STA WSYNC LDA #05 STA CTRLPF LDA D6 STA COLUP0 LDA D7 STA COLUP1 B10DF LDX #1E TXS ; Very Sneaky - set stack to missle registers SEC LDA A4 SBC B4 AND #FE TAX AND #F0 BEQ B10F2 LDA #00 BEQ B10F4 B10F2 LDA BD,X B10F4 STA WSYNC ; End of 1 line STA GRP0 LDA A7 EOR B4 AND #FE PHP ; This turns the missle 1 on/off LDA A6 EOR B4 AND #FE PHP ; This turns the missle 0 on/off LDA B4 BPL B110C EOR #F8 B110C CMP #20 BCC B1114 LSR A LSR A LSR A TAY B1114 LDA A5 SEC SBC B4 INC B4 NOP ORA #01 TAX AND #F0 BEQ B1127 LDA #00 BEQ B1129 B1127 LDA BD,X B1129 BIT 82 STA GRP1 BMI B113B LDA (B5),Y STA PF0 LDA (B7),Y STA PF1 LDA (B9),Y STA PF2 B113B INC B4 LDA B4 EOR #EC BNE B10DF LDX D3 ; Restore stack pointer TXS STA ENAM0 STA ENAM1 STA GRP0 STA GRP1 STA GRP0 STA PF0 STA PF1 STA PF2 RTS ; J1157 LDA SWCHB LSR A BCS B1170 LDA #0F STA 87 LDA #FF STA 88 LDA #80 STA DD LDX #E6 JSR J15BD ; zero out $89 thru $A2 BEQ B11D0 B1170 LDY #02 LDA DD AND 88 CMP #F0 BCC B1182 LDA 86 AND #30 BNE B1182 LDY #0E B1182 STY DC LDA 86 AND #3F BNE B1192 STA 89 INC DD BNE B1192 STA 88 B1192 LDA SWCHB AND #02 BEQ B119D STA 89 BNE B11F1 B119D BIT 89 BMI B11F1 INC 80 J11A3 LDX #DF B11A5 JSR J15BD LDA #FF STA 89 LDY 80 LDA L17D8,Y STA A3 EOR #FF BNE B11BB LDX #DD BNE B11A5 B11BB LDA 81 SED CLC ADC #01 STA 81 STA A1 CLD BIT A3 BPL B11D0 INC 85 BVC B11D0 INC 85 B11D0 JSR J1525 LDA #32 STA A5 LDA #86 STA A4 BIT A3 BMI B11F1 STA A5 STA POSH2 LDA #08 STA 96 LDA #20 STA HMP0 STA HMP1 STA WSYNC STA HMOVE B11F1 RTS ; J11F2 LDX #01 ; convert BCD scores to score pattern offset B11F4 LDA A1,X AND #0F STA D2 ASL A ASL A CLC ADC D2 STA E0,X LDA A1,X AND #F0 LSR A LSR A STA D2 LSR A LSR A CLC ADC D2 STA E2,X DEX BPL B11F4 RTS ; J1214 BIT 83 BVC B121C LDA #30 BPL B121E B121C LDA #20 B121E STA B1 LDX #03 JSR J1254 DEX JSR J1254 DEX B122A LDA 8D,X AND #08 LSR A LSR A STX D1 CLC ADC D1 TAY LDA 00A8,Y SEC BMI B123D CLC B123D ROL A STA 00A8,Y BCC B1250 LDA AC,X AND #01 ASL A ASL A ASL A ASL A STA B1 JSR J1254 B1250 DEX BEQ B122A RTS ; J1254 INC AC,X LDA 95,X AND #0F CLC ADC B1 TAY LDA L15F7,Y STA B0 BIT 82 BVS B127A LDA 95,X SEC SBC #02 AND #03 BNE B127A LDA AC,X AND #03 BNE B127A LDA #08 STA B0 B127A LDA B0 J127C STA HMP0,X AND #0F SEC SBC #08 STA D4 CLC ADC A4,X BIT A3 BMI B1290 CPX #02 BCS B12A0 B1290 CMP #DB BCS B1298 CMP #25 BCS B12A0 B1298 LDA #D9 BIT D4 BMI B12A0 LDA #28 B12A0 STA A4,X CPX #02 BCS B12A8 STA VDELP0,X B12A8 RTS ; J12A9 LDA #01 AND 86 TAX LDA 95,X STA REFP0,X AND #0F TAY BIT 83 BPL B12BB STY 97,X B12BB TXA EOR #0E TAX TYA ASL A ASL A ASL A CMP #3F CLC BMI B12CB SEC EOR #47 B12CB TAY B12CC LDA (BB),Y STA BD,X BCC B12D4 DEY DEY B12D4 INY DEX DEX BPL B12CC RTS ; J12DA LDA 8A SEC SBC #02 BCC B130C STA 8A CMP #02 BCC B130B AND #01 TAX INC 95,X LDA D8,X STA D6,X LDA 8A CMP #F7 BCC B12F9 JSR J1508 B12F9 LDA 8A BPL B130B LSR A LSR A LSR A J1300 STA AUDV0,X LDA #08 STA AUDC0,X LDA L17FE,X STA AUDF0,X B130B RTS ; B130C LDX #01 LDA SWCHB STA D5 LDA SWCHA B1316 BIT 88 BMI B131C LDA #FF B131C EOR #FF AND #0F STA D2 LDY 85 LDA L170F,Y CLC ADC D2 TAY LDA L1712,Y AND #0F STA D1 BEQ B1338 CMP 91,X BNE B133C B1338 DEC 93,X BNE B1349 B133C STA 91,X LDA #0F STA 93,X LDA D1 CLC ADC 95,X STA 95,X B1349 INC 8D,X BMI B136B LDA L1712,Y LSR A LSR A LSR A LSR A BIT D5 BMI B137B B1358 STA 8B,X ASL A TAY LDA L1637,Y STA A8,X INY LDA L1637,Y STA AA,X LDA #F0 STA 8D,X B136B JSR J1380 LDA SWCHA LSR A LSR A LSR A LSR A ASL D5 DEX BEQ B1316 RTS ; B137B SEC SBC 85 BPL B1358 J1380 LDA A3 BMI B138C AND #01 BEQ B138C LDA DB STA D6,X B138C LDA 99,X BEQ B13B7 LDA D8,X STA D6,X LDA 99,X CMP #07 BCC B13AE BIT D5 BPL B13A2 CMP #1C BCC B13AE B13A2 CMP #30 BCC B13C5 CMP #37 BCS B13CB BIT 83 BVC B13CB J13AE LDA #00 STA 99,X LDA #FF B13B4 STA RESMP0,X RTS ; B13B7 BIT 88 BPL B13BF LDA INPT4,X BPL B13F6 B13BF JSR J1410 JMP J13AE ; B13C5 JSR J1410 JMP J13DE ; J13CB LDA 9F,X BEQ B13D9 JSR J1410 LDA #30 STA 99,X JMP J13DE ; B13D9 LDA 99,X JSR J1300 J13DE LDA 86 AND #03 BEQ B13F0 BIT 84 BVS B13F2 BIT 82 BVC B13F0 AND #01 BNE B13F2 B13F0 DEC 99,X B13F2 LDA #00 BEQ B13B4 B13F6 LDA #3F STA 99,X SEC LDA A4,X SBC #06 STA A6,X LDA 95,X STA 97,X LDA #1F STA 9B,X LDA #00 STA 9D,X JMP J13CB ; J1410 LDA 9F,X BEQ B1421 LDA #04 STA AUDC0,X LDA #07 STA AUDV0,X LDA 9B,X STA AUDF0,X RTS ; B1421 LDY 85 LDA L1733,Y AND 88 STA AUDV0,X LDA L1736,Y STA AUDC0,X CLC LDA #00 B1432 DEY BMI B1439 ADC #0C BPL B1432 B1439 ADC 8B,X TAY TXA ASL A ADC L1739,Y STA AUDF0,X RTS ; J1444 LDX #01 J1446 LDA CXM0P,X BPL B1476 BIT 84 BVC B1454 LDA 9B,X CMP #1F BEQ B1476 B1454 INC 95,X INC 97,X SED LDA A1,X CLC ADC #01 STA A1,X CLD TXA CLC ADC #FD STA 8A LDA #FF STA RESMP0 STA RESMP1 LDA #00 STA AUDV0,X STA 99 STA 9A RTS ; B1476 BIT A3 BPL B147D JMP J1501 ; B147D LDA 9F,X BEQ B148B CMP #04 INC 9F,X BCC B148B LDA #00 STA 9F,X B148B LDA CXM0FB,X BMI B1496 LDA #00 STA 9D,X JMP J14D6 ; B1496 BIT 82 BVC B14D0 LDA 9D,X BNE B14B7 INC 9F,X DEC 9B,X LDA 97,X STA B2,X EOR #FF STA 97,X INC 97,X LDA 97,X AND #03 BNE B14B4 INC 97,X B14B4 JMP J14D4 ; B14B7 CMP #01 BEQ B14C6 CMP #03 BCC B14D4 BNE B14D4 LDA B2,X JMP J14C8 ; B14C6 LDA 97,X J14C8 CLC ADC #08 STA 97,X JMP J14D4 ; B14D0 LDA #01 STA 99,X J14D4 INC 9D,X J14D6 LDA CXP0FB,X BMI B14DE LDA CXPPMM BPL B14E7 B14DE LDA 8A CMP #02 BCC B14ED JSR J1508 B14E7 LDA #03 STA E4,X BNE B1501 B14ED DEC E4,X BMI B14F7 LDA 8B,X BEQ B1501 BNE B14F9 B14F7 INC 95,X B14F9 LDA 95,X CLC ADC #08 JSR J150F B1501 DEX BMI B1507 JMP J1446 B1507 RTS ; J1508 TXA EOR #01 TAY LDA 0097,Y J150F AND #0F TAY LDA L1627,Y JSR J127C LDA #00 STA A8,X STA AA,X STA 8D,X LDA D8,X STA D6,X RTS J1525 LDX 85 LDA L17C6,X STA BB LDA L17C9,X STA BC LDA A3 LSR A LSR A AND #03 TAX LDA A3 BPL B1546 AND #08 BEQ B1544 LDX #03 BPL B1548 B1544 LDA #80 B1546 STA 82 B1548 LDA A3 ASL A ASL A BIT A3 BMI B1556 STA WSYNC STA 84 AND #80 B1556 STA 83 LDA #F7 STA B6 STA B8 STA BA LDA L17CC,X STA RESP0 STA B5 LDA L17D0,X STA B7 LDA L17D4,X STA B9 RTS ; J1572 LDA A3 AND #87 BMI B157A LDA #00 B157A ASL A TAX LDA L175D,X STA NUSIZ0 LDA L175E,X STA NUSIZ1 LDA A3 AND #C0 LSR A LSR A LSR A LSR A TAY LDA 88 STA SWCHB EOR #FF AND DD STA D1 LDX #FF LDA SWCHB AND #08 BNE B15A7 LDY #10 LDX #0F B15A7 STX D2 LDX #03 B15AB LDA L1765,Y EOR D1 AND D2 STA COLUP0,X STA D6,X STA D8,X INY DEX BPL B15AB RTS ; J15BD LDA #00 B15BF INX STA A2,X BNE B15BF RTS ; ; Patterns for numbers ; L15C5 .BYTE $0E ,$0A ,$0A ,$0A ,$0E ; 0 leading zero suppressed .BYTE $22 ,$22 ,$22 ,$22 ,$22 ; 11 .BYTE $EE ,$22 ,$EE ,$88 ,$EE ; 22 .BYTE $EE ,$22 ,$66 ,$22 ,$EE ; 33 .BYTE $AA ,$AA ,$EE ,$22 ,$22 ; 44 .BYTE $EE ,$88 ,$EE ,$22 ,$EE ; 55 .BYTE $EE ,$88 ,$EE ,$AA ,$EE ; 66 .BYTE $EE ,$22 ,$22 ,$22 ,$22 ; 77 .BYTE $EE ,$AA ,$EE ,$AA ,$EE ; 88 .BYTE $EE ,$AA ,$EE ,$22 ,$EE ; 99 ; L15F7 .BYTE $F8 ,$F7 ,$F6 ,$06 ,$06 .BYTE $06 ,$16 ,$17 ,$18 ; $15FC .BYTE $19 ,$1A ,$0A ,$0A ; $1600 .BYTE $0A ,$FA ,$F9 ,$F8 ; $1604 .BYTE $F7 ,$F6 ,$F6 ,$06 ; $1608 .BYTE $16 ,$16 ,$17 ,$18 ; $160C .BYTE $19 ,$1A ,$1A ,$0A ; $1610 .BYTE $FA ,$FA ,$F9 ,$E8 ; $1614 .BYTE $E6 ,$E4 ,$F4 ,$04 ; $1618 .BYTE $14 ,$24 ,$26 ,$28 ; $161C .BYTE $2A ,$2C ,$1C ,$0C ; $1620 .BYTE $FC ,$EC ,$EA ; $1624 ; L1627 .BYTE $C8 ,$C4 ,$C0 ,$E0 ,$00 .BYTE $20 ,$40 ,$44 ,$48 .BYTE $4C ,$4F ,$2F ,$0F .BYTE $EF ,$CF ,$CC ; L1637 .BYTE $00 ,$00 ,$80 ,$80 ,$84 .BYTE $20 ,$88 ,$88 ,$92 ; $163C .BYTE $48 ,$A4 ,$A4 ,$A9 ; $1640 .BYTE $52 ,$AA ,$AA ,$D5 ; $1644 .BYTE $AA ,$DA ,$DA ,$DB ; $1648 .BYTE $6D ,$EE ,$EE ,$00 ; $164C .BYTE $FC ,$FC ,$38 ,$3F ; $1650 .BYTE $38 ,$FC ,$FC ,$1C ; $1654 .BYTE $78 ,$FB ,$7C ,$1C ; $1658 .BYTE $1F ,$3E ,$18 ,$19 ; $165C .BYTE $3A ,$7C ,$FF ,$DF ; $1660 .BYTE $0E ,$1C ,$18 ,$24 ; $1664 .BYTE $64 ,$79 ,$FF ,$FF ; $1668 .BYTE $4E ,$0E ,$04 ,$08 ; $166C .BYTE $08 ,$6B ,$7F ,$7F ; $1670 .BYTE $7F ,$63 ,$63 ,$24 ; $1674 .BYTE $26 ,$9E ,$FF ,$FF ; $1678 .BYTE $72 ,$70 ,$20 ,$98 ; $167C .BYTE $5C ,$3E ,$FF ,$FB ; $1680 .BYTE $70 ,$38 ,$18 ,$38 ; $1684 .BYTE $1E ,$DF ,$3E ,$38 ; $1688 .BYTE $F8 ,$7C ,$18 ,$60 ; $168C .BYTE $70 ,$78 ,$FF ,$78 ; $1690 .BYTE $70 ,$60 ,$00 ,$00 ; $1694 .BYTE $C1 ,$FE ,$7C ,$78 ; $1698 .BYTE $30 ,$30 ,$30 ,$00 ; $169C .BYTE $03 ,$06 ,$FC ,$FC ; $16A0 .BYTE $3C ,$0C ,$0C ,$02 ; $16A4 .BYTE $04 ,$0C ,$1C ,$FC ; $16A8 .BYTE $FC ,$1E ,$06 ,$10 ; $16AC .BYTE $10 ,$10 ,$38 ,$7C ; $16B0 .BYTE $FE ,$FE ,$10 ,$40 ; $16B4 .BYTE $20 ,$30 ,$38 ,$3F ; $16B8 .BYTE $3F ,$78 ,$60 ,$40 ; $16BC .BYTE $60 ,$3F ,$1F ,$1E ; $16C0 .BYTE $1E ,$18 ,$18 ,$00 ; $16C4 .BYTE $83 ,$7F ,$3E ,$1E ; $16C8 .BYTE $0C ,$0C ,$0C ,$00 ; $16CC .BYTE $8E ,$84 ,$FF ,$FF ; $16D0 .BYTE $04 ,$0E ,$00 ,$00 ; $16D4 .BYTE $0E ,$04 ,$8F ,$7F ; $16D8 .BYTE $72 ,$07 ,$00 ,$10 ; $16DC .BYTE $36 ,$2E ,$0C ,$1F ; $16E0 .BYTE $B2 ,$E0 ,$40 ,$24 ; $16E4 .BYTE $2C ,$5D ,$1A ,$1A ; $16E8 .BYTE $30 ,$F0 ,$60 ,$18 ; $16EC .BYTE $5A ,$7E ,$5A ,$18 ; $16F0 .BYTE $18 ,$18 ,$78 ,$34 ; $16F4 .BYTE $36 ,$5A ,$78 ,$2C ; $16F8 .BYTE $0C ,$06 ,$0C ,$08 ; $16FC .BYTE $6C ,$70 ,$B8 ,$DC ; $1700 .BYTE $4E ,$07 ,$06 ,$38 ; $1704 .BYTE $10 ,$F0 ,$7C ,$4F ; $1708 .BYTE $E3 ,$02 ,$00 ; $170C ; L170F .BYTE $00 ,$0B ,$16 L1712 .BYTE $00 ,$10 .BYTE $00 ,$FF ,$01 ,$11 ; $1714 .BYTE $01 ,$FF ,$0F ,$1F ; $1718 .BYTE $0F ,$50 ,$5F ,$51 ; $171C .BYTE $FF ,$30 ,$3F ,$31 ; $1720 .BYTE $FF ,$70 ,$7F ,$71 ; $1724 .BYTE $90 ,$B0 ,$70 ,$FF ; $1728 .BYTE $91 ,$B1 ,$71 ,$FF ; $172C .BYTE $9F ,$BF ,$7F ; $1730 ; L1733 .BYTE $08 ,$02 ,$02 ; sound volumes L1736 .BYTE $02 ,$03 ,$08 ; sound types L1739 .BYTE $1D ,$05 ,$00 ; sound pitches .BYTE $00 ,$00 ,$00 ,$00 ; $173C .BYTE $00 ,$00 ,$00 ,$00 ; $1740 .BYTE $00 ,$00 ,$00 ,$1D ; $1744 .BYTE $1D ,$16 ,$16 ,$0F ; $1748 .BYTE $0F ,$00 ,$00 ,$00 ; $174C .BYTE $00 ,$00 ,$00 ,$00 ; $1750 .BYTE $00 ,$00 ,$12 ,$10 ; $1754 .BYTE $10 ,$0C ,$0C ,$07 ,$07 ; $1758 ; L175D .BYTE $00 L175E .BYTE $00 ,$01 .BYTE $01 ,$00 ,$03 ,$27 ,$03 ; L1765 .BYTE $EA ,$3C ,$82 .BYTE $44 ,$32 ,$2C ,$8A ; $1768 .BYTE $DA ,$80 ,$9C ,$DA ; $176C .BYTE $3A ,$64 ,$A8 ,$DA ; $1770 .BYTE $4A ,$08 ,$04 ,$00 ; $1774 .BYTE $0E ,$F0 ,$10 ,$10 ; $1778 .BYTE $10 ,$10 ,$10 ,$10 ; $177C .BYTE $10 ,$10 ,$10 ,$10 ; $1780 .BYTE $10 ,$FF ,$00 ,$00 ; $1784 .BYTE $00 ,$38 ,$00 ,$00 ; $1788 .BYTE $00 ,$60 ,$20 ,$20 ; $178C .BYTE $23 ,$FF ,$80 ,$80 ; $1790 .BYTE $00 ,$00 ,$00 ,$1C ; $1794 .BYTE $04 ,$00 ,$00 ,$00 ; $1798 .BYTE $00 ,$FF ,$00 ,$00 ; $179C .BYTE $00 ,$00 ,$00 ,$00 ; $17A0 .BYTE $00 ,$00 ,$00 ,$00 ; $17A4 .BYTE $00 ,$00 ,$07 ,$1F ; $17A8 .BYTE $3F ,$7F ,$FF ,$00 ; $17AC .BYTE $00 ,$00 ,$00 ,$00 ; $17B0 .BYTE $00 ,$00 ,$00 ,$60 ; $17B4 .BYTE $20 ,$21 ,$FF ,$00 ; $17B8 .BYTE $00 ,$00 ,$80 ,$80 ; $17BC .BYTE $80 ,$80 ,$00 ,$00 ; $17C0 .BYTE $00 ,$07 ; L17C6 .BYTE $4F ,$CF ,$8F L17C9 .BYTE $F6 ,$F6 ,$F6 L17CC .BYTE $75 ,$75 ,$75 ,$9A L17D0 .BYTE $81 ,$99 ,$AA ,$9D L17D4 .BYTE $8D ,$99 ,$B6 ,$9D L17D8 .BYTE $24 ,$28 ,$08 ,$20 .BYTE $00 ,$48 ,$40 ,$54 ; $17DC .BYTE $58 ,$25 ,$29 ,$49 ; $17E0 .BYTE $55 ,$59 ,$A8 ,$88 ; $17E4 .BYTE $98 ,$90 ,$A1 ,$83 ; $17E8 .BYTE $E8 ,$C8 ,$E0 ,$C0 ; $17EC .BYTE $E9 ,$E2 ,$C1 ,$FF ; $17F0 .BYTE $00 ,$00 ,$00 ,$00 ; $17F4 .BYTE $00 ,$00 ; .WORD $0000 ; NMI .WORD $F000 ; Reset L17FE .BYTE $0F, $11 ; IRQ - (used as pitch for sound generator) -- Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu Western Michigan University Computer Science Department Voice: (616) 387-5803 Kalamazoo, MI 49008
dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
Atari 2600 Stella Memory Map Write Address Registers Addr Assy Name Bits Used Function 00 Vsync 0000 00x0 Vertical Sync Set-Clear 01 Vblank xx00 00x0 Vertical Blank Set-Clear 02 Wsync ---- ---- Wait for Horizontal Blank 03 Rsync ---- ---- Reset Horizontal Sync Counter 04 Nusiz0 00xx 0xxx Number-Size player/missle 0 05 Nusiz1 00xx 0xxx Number-Size player/missle 1 06 Colup0 xxxx xxx0 Color-Luminance Player 0 07 Colup1 xxxx xxx0 Color-Luminance Player 1 08 Colupf xxxx xxx0 Color-Luminance Playfield 09 Colubk xxxx xxx0 Color-Luminance Background 0A Ctrlpf 00xx 0xxx Control Playfield, Ball, Collisions 0B Refp0 0000 x000 Reflection Player 0 0C Refp1 0000 x000 Reflection Player 1 0D Pf0 xxxx 0000 Playfield Register Byte 0 0E Pf1 xxxx xxxx Playfield Register Byte 1 0F Pf2 xxxx xxxx Playfield Register Byte 2 10 Resp0 ---- ---- Reset Player 0 11 Resp1 ---- ---- Reset Player 1 12 Resm0 ---- ---- Reset Missle 0 13 Resm1 ---- ---- Reset Missle 1 14 Resbl ---- ---- Reset Ball 15 Audc0 0000 xxxx Audio Control 0 16 Audc1 0000 xxxx Audio Control 1 17 Audf0 000x xxxx Audio Frequency 0 18 Audf1 000x xxxx Audio Frequency 1 19 Audv0 0000 xxxx Audio Volume 0 1A Audv1 0000 xxxx Audio Volume 1 1B Grp0 xxxx xxxx Graphics Register Player 0 1C Grp1 xxxx xxxx Graphics Register Player 1 1D Enam0 0000 00x0 Graphics Enable Missle 0 1E Enam1 0000 00x0 Graphics Enable Missle 1 1F Enabl 0000 00x0 Graphics Enable Ball 20 Hmp0 xxxx 0000 Horizontal Motion Player 0 21 Hmp1 xxxx 0000 Horizontal Motion Player 1 22 Hmm0 xxxx 0000 Horizontal Motion Missle 0 23 Hmm1 xxxx 0000 Horizontal Motion Missle 1 24 Hmbl xxxx 0000 Horizontal Motion Ball 25 Vdelp0 0000 000x Vertical Delay Player 0 26 Vdelp1 0000 000x Vertical Delay Player 1 27 Vdelbl 0000 000x Vertical Delay Ball 28 Resmp0 0000 00x0 Reset Missle 0 to Player 0 29 Resmp1 0000 00x0 Reset Missle 1 to Player 1 2A Hmove ---- ---- Apply Horizontal Motion 2B Hmclr ---- ---- Clear Horizontal Move Registers 2C Cxclr ---- ---- Clear Collision Latches Read Address Registers bit 6 bit 7 0 Cxm0p xx00 0000 Read Collision M0-P1 M0-P0 1 Cxm1p xx00 0000 M1-P0 M1-P1 2 Cxp0fb xx00 0000 P0-PF P0-BL 3 Cxp1fb xx00 0000 P1-PF P1-BL 4 Cxm0fb xx00 0000 M0-PF M0-BL 5 Cxm1fb xx00 0000 M1-PF M1-BL 6 Cxblpf x000 0000 BL-PF ----- 7 Cxppmm xx00 0000 P0-P1 M0-M1 8 Inpt0 x000 0000 Read Pot Port 0 9 Inpt1 x000 0000 Read Pot Port 1 A Inpt2 x000 0000 Read Pot Port 2 B Inpt3 x000 0000 Read Pot Port 3 C Inpt4 x000 0000 Read Input (Trigger) 0 D Inpt5 x000 0000 Read Input (Trigger) 1 Atari 2600 RIOT Memory Map 80-FF Ram also at 180-1FF 280 Swcha Port A data register (joysticks...) 281 Swacnt Port A data direction register (DDR) 282 Swchb Port B data (console switches) 283 Swbcnt Port B DDR 284 Intim Timer output 294 Tim1t set 1 clock interval 295 Tim8t set 8 clock interval 296 Tim64t set 64 clock interval 297 T1024t set 1024 clock interval these are also at 380-397 Atari 2600 ROM Memory Map E000-FFFF Rom also 1000-1FFF 3000-3FFF .... -- Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu Western Michigan University Computer Science Department Voice: (616) 387-5803 Kalamazoo, MI 49008
dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
Wsync Wait for sync
This address halts microprocessor by clearing RDY latch to zero. RDY is
set true again by the leading edge of horizontal blank.
Data bits not used.
---
Rsync Reset Sync
This address resets the horizontal sync counter to define the begining of
horizontal blank time, and is used in chip testing.
Data bits not used.
---
Vsync
This address controls vertical sync time by writing D1 into the Vsync latch.
D1 - 1: start vertical sync
0: stop vertical sync
---
Vblank
This address controls vertical blank and the latches and dumping transistors
on the input ports by writing into bits D7,D6, and D1 of the Vblank register.
D1 - 1: start vertical blank
0: stop vertical blank
D6 - 1: enable I4 and I5 latches
0: disable latches - also resets latches to logic true
D7 - 1: Dump I0,I1,I2,I3 ports to ground
0: Remove dump path to ground
---
Pf0, Pf1, Pf2
These addresses are used to write into the playfield registers.
horizontal scan line map
(160 clocks, each bit =4 clocks)
Ctrlpf bit 0
bits 4-7 7-0 0-7 | 4-7 7-0 0-7
register Pf0 Pf1 Pf2 Pf0 Pf1 Pf2 0
bits 4-7 7-0 0-7 | 7-0 0-7 7-4
register Pf0 Pf1 Pf2 Pf2 Pf1 Pf0 1
---
Ctrlpf
This address is used to write into the playfield control register.
if bit is 1 then:
D0 - (REF) reflect playfield, see above
D1 - (SCORE) left half of playfield gets color of player 0
right half gets color of player 1
D2 - (PFP) playfield gets priority over players so they move
behind playfield
D5,D4 - Ball Size if 00, 1 clock wide
if 01, 2 clocks wide
if 10, 4 clocks wide
if 11, 8 clocks wide
---
Nusiz0, Nusiz1
These addresses control the number and size of players and missles.
D5,D4 - Missle Size see Ball Size above
D2,D1,D0 - Player number/size
if 000, X one copy
if 001, X X two copies, close
if 010, X X two copies, medium
if 011, X X X three copies, close
if 100, X X Two copies, far
if 101, XX one copy, double width
if 110, X X X 3 copies, medium
if 111, XXXX one copy, quad width
---
Resp0, Resp1, Resm0, Resm1, Resbl
These addresses are used to reset players, missles and the ball. The object
will begin its serial graphics at that time of a horizontal line at which the
reset address occurs.
Data bits not used.
---
Resmp0, Resmp1
These addresses are used to reset the horizontal location of a missle to
the center of its corresponding player. As long as this control bit is
true (1), the misslw will remain locked to the center of its player and the missle graphics will be disabled. When a zero is written into this location,
the missle is enabled, and can be moved independently from the player.
D1 - 0: allow missle to move
1: lock missle to player
---
Hmove
This address causes the horizontal motion register values to be acted upon
during the horizontal blank time in which it occurs. It must occur at the
beginning of horizontal blanking in order to allow time for generation of
extra clock pulses into the horizontal position counters. If motion is
desired, this command must immediately follow a Wsync command in the program.
Data bits not used.
---
Hmclr
This address clears all horizontal motion registers to zero (no motion).
Data bits not used.
---
Hmp0, Hmp1, Hmm0, Hmm1, Hmbl
These addresses write data (horizontal motion values) into the horizontal
motion registers. These registers cause horizontal motion only when commanded
to do so by the horizontal movement command Hmove. The motion values use the
upper 4 bits of the byte. They are signed numbers with a +7 to -8 range. The
positive numbers indicate left movement, the negative indicate right.
Warning: These registers should not be modified during the 24 computer cycles
following an Hmove command. Unpredictable motion values may result.
---
Enam0, Enam1, Enabl
These addresses write into the single bit missle or ball graphics registers.
D1 - 0: disables object
1: enables object
---
Grp0, Grp1
These addresses write data into the player graphics registers
horizontal scan line map
(each bit =1 clock)
bits 7-0 if Refp0 (Refp1) is 0
bits 0-7 if Refp0 (Refp1) is 1 (reflected)
---
Refp0, Refp1
These addresses write data into the the single bit player reflect registers.
see above.
D3 - 0: normal
1: reflected
---
Vdelp0, Vdelp1, Vdelbl
These addresses write data into the single bit vertical delay registers, to
delay players or the ball by one vertical line.
D0 - 0: no delay
1: delayed
---
Cxclr
This address clears all collision latches to zero (no collision)
Data bits not used.
---
Colupb, Colup1, Colupf, Colubk
These addresses write data into the player, playfield, and background
color-luminance registers.
D3, D2, D1 - Luminance values 000 is dark, 111 is bright.
D7,D6,D5,D4 - Colors 0000 Grey
0001 Gold
0010 Orange
0011 Red orange
0100 Pink
0101 Purple
0110 Blue purple
0111 Blue
1000 Blue
1001 Light blue
1010 Turquoise
1011 Green blue
1100 Green
1101 Yellow green
1110 Orange green
1111 Light orange
---
Audf0, Audf1
These addresses write data into the audio frequency divider registers.
D4,D3,D2,D1,D0 - 00000 30KHz divided by 1
00001 " " 2
.....
11111 " " 32
---
Audc0, Audc1
These addresses write data into the audio control registers which control
the noise content and additional division of the audio output.
bits value noise type division
D3, D2, D1, D0 - 0000 set to 1
0001 4 bit poly
0010 /15 into 4 bit poly
0011 5 bit poly into 4 bit poly
0100 divide by 2
0101 divide by 2
0110 divide by 31
0111 5 bit poly into /2
1000 9 bit poly
1001 5 bit poly
1010 divide by 31
1011 set last 4 bits to 1
1100 divide by 6
1101 divide by 6
1110 divide by 93
1111 5 bit poly divided by 6
---
Audv0, Audv1
These addresses write data into the audio volume registers which set the pull
down impedance driving the audio output pads.
D3, D2, D1, D0 - 0000 no output
....
1111 loudest output
---
End
--
Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu
Western Michigan University
Computer Science Department Voice: (616) 387-5803
Kalamazoo, MI 49008dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
; Color Demo ; Taken from the Magicard Manual ; shows almost all the colors on the left side ; of the screen and cycles slowly on the right ; Start LDA $81 ; get contents of memory STA $0F ; save into a pattern control register LDA #$03 STA $0A ; set background control register LDA #$55 STA $07 ; set right side color LDY #$00 DEY STA $02 ; wait for horizontal sync STA $01 ; start vertical blanking STA $00 ; start vertical retrace LDA #$2A STA $0295 ; set timer for appropriate length Loop1 LDY $0284 BNE Loop1 ; waste time STY $02 ; wait for horizontal sync STY $00 ; end vertical retrace period LDA #$24 STA $0296 ; set timer for next wait LDA $0282 AND #$01 ; check for reset switch BNE NReset BRK ; only interrupt available - must have vector set NReset INC $80 ; increment right side color cycle counter BNE Loop2 LDA #$E0 STA $80 ; reset counter INC $81 LDA $81 ; increment right side color STA $06 ; store it in color register Loop2 LDY $0284 BNE Loop2 ; waste time STY $02 ; wait for horizontal sync STY $01 ; end vertical blanking LDX #$E4 ; number of line to draw on screen Loop3 STY $02 ; wait for horizontal sync STX $0E ; change a background pattern with each line STX $07 ; change right side color with each line DEX BNE loop3 JMP Start ; do next screen (every 1/60th second) .END -- Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu Western Michigan University Computer Science Department Voice: (616) 387-5803 Kalamazoo, MI 49008
dodgson@cs.wmich.edu (Harry Dodgson) (01/28/89)
; Billboard Demo ; displays sonething close to, but not quite like ; the colored billboard used in "Close Encounters..." ; just a small demo to see what could be done ; Start LDX #$FF TXS JSR Sub0 LDA #$06 STA $09 LDA #$02 STA $0A LDA #$35 STA $B1 STA $B4 LDA $1B STA $B2 STA $B3 LDA #$00 STA $B6 LDA #$AA STA $B5 Main JSR Sub1 LDA #$50 STA $06 LDA #$80 STA $07 LDA #$08 STA $19 JSR Sub2 LDA $0282 AND #$02 BEQ Start JSR Sub3 LDX #$10 Loop1 NOP STY $02 DEX BNE Loop1 LDY #$06 LDX #$04 Loop2 STY #$02 LDA $B1 STA $0D LDA $B2 STA $0E LDA $B3 STA $0F NOP NOP NOP NOP NOP NOP NOP LDA $B4 STA $0D LDA $B5 STA $0E LDA $B6 STA $0F DEX BNE Loop2 LDA #$06 STA $06 STA $07 LDX #$A6 Loop3 NOP STY $02 DEX BNE Loop3 JMP Main Sub0 CLD SEI LDX #$00 STX $0281 STX $0283 LDY #$04 Loc0 STX $00,Y INY CPY #$20 BNE Loc0 STX $2B RTS Sub1 LDY #$FF STY $02 STY $01 STY $00 LDA #$2A STA $0295 LDA $0282 AND #$01 BNE Loc1 BRK Loc1 RTS Sub2 LDY $0284 BNE Sub2 STY $02 STY $00 LDA #$19 STA $0296 RTS Sub3 LDY $0284 BNE Sub3 STY $02 STY $01 STY $2A RTS .END -- Harry Dodgson Jr. Internet: dodgson@cs.wmich.edu Western Michigan University Computer Science Department Voice: (616) 387-5803 Kalamazoo, MI 49008