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WIP fucking video generation

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Daniele Verducci su MatissePenguin 2021-01-07 09:14:09 +01:00
parent 06779c5442
commit 0b88c7d0db
2 changed files with 53 additions and 47 deletions
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8
pat80-io-devices/composite-pal-adapter/software/avr-assembly/atmega1284definition.asm
View File

@ -1,3 +1,11 @@
; ***** CPU REGISTER DEFINITIONS *****************************************
.def XH = r27
.def XL = r26
.def YH = r29
.def YL = r28
.def ZH = r31
.def ZL = r30
; ***** I/O REGISTER DEFINITIONS *****************************************
; NOTE:
; Definitions marked "MEMORY MAPPED"are extended I/O ports

92
pat80-io-devices/composite-pal-adapter/software/avr-assembly/main.asm
View File

@ -23,32 +23,34 @@ main:
out DDRD, r16 ; set port as output
; Load ram addr into register X
ldi r16,0x00
mov r0,r16
ldi r16,0x01
mov r1,r16
mov XL,r0
mov XH,r1
;*** Load data into ram ***
;ldi r27, 0x01
;ldi r26, 0x00
; load data
ldi r16, 255
load_mem_loop:
ldi r17, 1
;sts X, r17
sts 0x0100, r17
adiw XH:XL, 1 ; increment X
dec r16 ; decrement outside counter
brne load_mem_loop ; if not 0, repeat h_picture_loop
; DEBUG: loads some static data in ram
ldi r18, 255
fill_mem_loop1:
st X+, r18
dec r18
brne fill_mem_loop1
; END DEBUG
v_refresh_loop:
; reset memory position counter
;ldi XL, 0x00
;ldi XH, 0x01
ldi r16,0x00
mov r0,r16
ldi r16,0x01
mov r1,r16
mov XL,r0
mov XH,r1
; ldi r16,0x00
; mov r0,r16
; ldi r16,0x01
; mov r1,r16
; mov XL,r0
; mov XH,r1
; set X register to framebuffer start
; ldi r27, 0x01
; ldi r26, 0x00
; start 5 long sync pulses
call long_sync
@ -72,43 +74,39 @@ v_refresh_loop:
ldi r17, 152 ; line counter
h_picture_loop:
call line_sync
; start line pixels: 52uS, 1247 cycles @ 24Mhz
; start line pixels: 52uS, 1248 cycles @ 24Mhz
ldi r18, 52 ; 1 cycle
l_sync_video_loop: ; 24 cycles
; Load a byte from memory into PORTD register and increment the counter.
; This also displays byte's MSB pixel "for free", as the video pin is PD7
; (last bit of PORTD).
;ld r19, X+ ; 2 cycles
ld r19, X ; 1 cycle
nop
lds r19, 0x0100 ; 2 cycles
out PORTD, r19 ; 1 cycle
; Shift the byte to the left to show another bit (do it 7 times)
lsl r19 ; 1 cycle
out PORTD, r19
nop
lsl r19 ; 1 cycle
out PORTD, r19
nop
lsl r19 ; 1 cycle
out PORTD, r19
nop
lsl r19 ; 1 cycle
out PORTD, r19
nop
lsl r19 ; 1 cycle
out PORTD, r19
nop
lsl r19 ; 1 cycle
out PORTD, r19
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
rol r19 ; 1 cycle
out PORTD, r19 ; 1 cycle
nop ; 1 cycle
dec r18 ; 1 cycle
brne l_sync_video_loop ; 2 cycles if jumps (1 if continues)
brne l_sync_video_loop ; 2 cycles if jumps (1 if continues)
; end line pixels
cbi PORTD, VIDEO_PIN ; video pin goes low before sync
dec r17 ; decrement line counter
dec r17 ; decrement line countr
brne h_picture_loop ; if not 0, repeat h_picture_loop
dec r16 ; decrement outside counter