mirror of https://github.com/wwarthen/RomWBW.git
19 changed files with 292 additions and 5 deletions
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;================================================================================================== |
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; Z80 DMA DRIVER FOR ECB-DMA |
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;================================================================================================== |
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; |
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; DUE TO LOW CLOCK SPEED CONTRAINTS OF Z80 DMA CHIP, THE HALF CLOCK FACILITY |
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; IS USED DURING DMA PROGRAMMING AND CONTINUOUS BLOCK TRANSFERS. |
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; TESTING CONDUCTED ON A SBC-V2-005 @ 10Mhz |
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; |
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DMA_CONTINUOUS .equ %10111101 ; + Pulse |
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DMA_BYTE .equ %10011101 ; + Pulse |
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DMA_BURST .equ %11011101 ; + Pulse |
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DMA_LOAD .equ $cf ; %11001111 |
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DMA_ENABLE .equ $87 ; %10000111 |
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DMA_FORCE_READY .equ $b3 |
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DMA_DISABLE .equ $83 |
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; |
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;DMA_RESET .equ $c3 |
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;DMA_RESET_PORT_A_TIMING .equ $c7 |
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;DMA_RESET_PORT_B_TIMING .equ $cb |
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;DMA_CONTINUE .equ $d3 |
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;DMA_DISABLE_INTERUPTS .equ $af |
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;DMA_ENABLE_INTERUPTS .equ $ab |
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;DMA_RESET_DISABLE_INTERUPTS .equ $a3 |
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;DMA_ENABLE_AFTER_RETI .equ $b7 |
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;DMA_READ_STATUS_BYTE .equ $bf |
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;DMA_REINIT_STATUS_BYTE .equ $8b |
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;DMA_START_READ_SEQUENCE .equ $a7 |
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;DMA_WRITE_REGISTER_COMMAND .equ $bb |
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; |
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;================================================================================================== |
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; DMA INITIALIZATION CODE |
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;================================================================================================== |
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; |
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DMA_INIT: |
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CALL NEWLINE |
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PRTS("DMA: IO=0x$") |
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LD A, DMABASE |
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CALL PRTHEXBYTE |
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; |
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ld a,0 |
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out (DMABASE+1),a ; force ready off |
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; |
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ld hl,DMACode ; program the |
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ld b,DMACode_Len ; dma command |
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ld c,DMABASE ; block |
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; |
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ld a,(RTCVAL) |
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or %00001000 ; half |
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out (112),a ; clock |
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di |
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otir ; load dma |
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ei |
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and %11110111 ; full |
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out (112),a ; clock |
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ret |
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; |
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DMACode ;.db DMA_DISABLE ; R6-Command Disable DMA |
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.db %01111101 ; R0-Transfer mode, A -> B, start address, block length follow |
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.dw 0 ; R0-Port A, Start address |
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.dw 0 ; R0-Block length |
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.db %00010100 ; R1-No timing bytes follow, address increments, is memory |
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.db %00010000 ; R2-No timing bytes follow, address increments, is memory |
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.db %10000000 ; R3-DMA, interrupt, stop on match disabled |
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.db DMA_CONTINUOUS ; R4-Continuous mode, destination address, interrupt and control byte follow |
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.dw 0 ; R4-Port B, Destination address |
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.db %00001100 ; R4-Pulse byte follows, Pulse generated |
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.db 0 ; R4-Pulse offset |
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.db %10011010 ; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH |
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.db DMA_LOAD ; R6-Command Load |
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; .db DMA_FORCE_READY ; R6-Command Force ready |
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; .db DMA_ENABLE ; R6-Command Enable DMA |
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DMACode_Len .equ $-DMACode |
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; |
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;================================================================================================== |
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; DMA COPY BLOCK CODE - ASSUMES DMA PREINITIALIZED |
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;================================================================================================== |
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; |
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DMALDIR: |
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ld (DMASource),hl ; populate the dma |
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ld (DMADest),de ; register template |
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ld (DMALength),bc |
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; |
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ld hl,DMACopy ; program the |
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ld b,DMACopy_Len ; dma command |
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ld c,DMABASE ; block |
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; |
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ld a,(RTCVAL) |
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or %00001000 ; half |
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out (112),a ; clock |
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di |
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otir ; load and execute dma |
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ei |
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and %11110111 ; full |
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out (112),a ; clock |
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ret |
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; |
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DMACopy ;.db DMA_DISABLE ; R6-Command Disable DMA |
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.db %01111101 ; R0-Transfer mode, A -> B, start address, block length follow |
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DMASource .dw 0 ; R0-Port A, Start address |
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DMALength .dw 0 ; R0-Block length |
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.db %00010100 ; R1-No timing bytes follow, address increments, is memory |
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.db %00010000 ; R2-No timing bytes follow, address increments, is memory |
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.db %10000000 ; R3-DMA, interrupt, stop on match disabled |
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.db DMA_CONTINUOUS ; R4-Continuous mode, destination address, interrupt and control byte follow |
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DMADest .dw 0 ; R4-Port B, Destination address |
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.db %00001100 ; R4-Pulse byte follows, Pulse generated |
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.db 0 ; R4-Pulse offset |
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; .db %10011010 ; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH |
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.db DMA_LOAD ; R6-Command Load |
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.db DMA_FORCE_READY ; R6-Command Force ready |
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.db DMA_ENABLE ; R6-Command Enable DMA |
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DMACopy_Len .equ $-DMACopy |
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; |
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;================================================================================================== |
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; DMA I/O OUT BLOCK CODE - ADDRESS TO I/O PORT |
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;================================================================================================== |
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; |
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DMAOTIR: |
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ld (DMAOutSource),hl ; populate the dma |
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ld (DMAOutDest),a ; register template |
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ld (DMAOutLength),bc |
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; |
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ld hl,DMAOutCode ; program the |
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ld b,DMAOut_Len ; dma command |
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ld c,DMABASE ; block |
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; |
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ld a,(RTCVAL) |
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or %00001000 ; half |
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out (112),a ; clock |
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di |
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otir ; load and execute dma |
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ei |
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and %11110111 ; full |
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out (112),a ; clock |
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ret |
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; |
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DMAOutCode ;.db DMA_DISABLE ; R6-Command Disable DMA |
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.db %01111001 ; R0-Transfer mode, B -> A (temp), start address, block length follow |
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DMAOutSource .dw 0 ; R0-Port A, Start address |
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DMAOutLength .dw 0 ; R0-Block length |
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|
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.db %00010100 ; R1-No timing bytes follow, fixed incrementing address, is memory |
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.db %00101000 ; R2-No timing bytes follow, address static, is i/o |
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.db %10000000 ; R3-DMA, interrupt, stop on match disabled |
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|
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.db %10100101 ; R4-Continuous mode, destination port, interrupt and control byte follow |
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DMAOutDest .db 0 ; R4-Port B, Destination port |
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; .db %00001100 ; R4-Pulse byte follows, Pulse generated |
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; .db 0 ; R4-Pulse offset |
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|
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.db %10011010 ; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH |
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.db DMA_LOAD ; R6-Command Load |
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.db %00000101 ; R0-Port A is Source |
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.db DMA_LOAD ; R6-Command Load |
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.db DMA_FORCE_READY ; R6-Command Force ready |
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.db DMA_ENABLE ; R6-Command Enable DMA |
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DMAOut_Len .equ $-DMAOutCode |
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; |
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;================================================================================================== |
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; DMA I/O INPUT BLOCK CODE - I/O PORT TO ADDRESS |
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;================================================================================================== |
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; |
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DMAINIR: |
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ld (DMAInDest),hl ; populate the dma |
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ld (DMAInSource),a ; register template |
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ld (DMAInLength),bc |
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; |
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ld hl,DMAInCode ; program the |
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ld b,DMAIn_Len ; dma command |
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ld c,DMABASE ; block |
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; |
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ld a,(RTCVAL) |
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or %00001000 ; half |
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out (112),a ; clock |
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di |
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otir ; load and execute dma |
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ei |
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and %11110111 ; full |
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out (112),a ; clock |
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ret |
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; |
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DMAInCode ;.db DMA_DISABLE ; R6-Command Disable DMA |
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.db %01111001 ; R0-Transfer mode, B -> A, start address, block length follow |
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DMAInDest .dw 0 ; R0-Port A, Start address |
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DMAInLength .dw 0 ; R0-Block length |
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.db %00010100 ; R1-No timing bytes follow, address increments, is memory |
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.db %00111000 ; R2-No timing bytes follow, address static, is i/o |
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.db %10000000 ; R3-DMA, interrupt, stop on match disabled |
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.db %10100101 ; R4-Continuous mode, destination port, no interrupt, control byte. |
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DMAInSource .db 0 ; R4-Port B, Destination port |
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; .db %00001100 ; R4-Pulse byte follows, Pulse generated |
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; .db 0 ; R4-Pulse offset |
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.db %10011010 ; R5-Stop on end of block, ce/wait multiplexed, READY active HIGH |
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.db DMA_LOAD ; R6-Command Load |
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.db DMA_FORCE_READY ; R6-Command Force ready |
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.db DMA_ENABLE ; R6-Command Enable DMA |
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|
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DMAIn_Len .equ $-DMAInCode |
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