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NS76489 digital pin order is fucking inverted! D0 is the MSB, D7 the LSB.

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Daniele Verducci su MatissePenguin 2020-12-06 14:09:48 +01:00
parent 3d4d5360c1
commit 97795c8111
1 changed files with 14 additions and 6 deletions
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20
assembly/bios/drivers/sn76489.asm
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@ -8,6 +8,9 @@
; Sound card is on port 0 ; Sound card is on port 0
SND_DATA_REG: EQU IO_0 SND_DATA_REG: EQU IO_0
; Settings
SND_BEEP_DURATION: EQU 1000 ; in cpu cycles
; Init device (silence all channels) ; Init device (silence all channels)
; Bits meaning: ; Bits meaning:
; 1 R0 R1 R2 A0 A1 A2 A3 ; 1 R0 R1 R2 A0 A1 A2 A3
@ -16,22 +19,20 @@ SND_DATA_REG: EQU IO_0
; Bit4,5,6,7 selecy the attenuation (0000=full volume, 1111=silent) ; Bit4,5,6,7 selecy the attenuation (0000=full volume, 1111=silent)
Snd_init: Snd_init:
; silence ch1 ; silence ch1
ld a,%11111001 ld a,%10011111
;ld a,%10011111
out (SND_DATA_REG),a out (SND_DATA_REG),a
; silence ch2 ; silence ch2
ld a,%11111101 ld a,%10111111
;ld a,%10111111
out (SND_DATA_REG),a out (SND_DATA_REG),a
; silence ch3 ; silence ch3
ld a,%11111011 ld a,%11011111
;ld a,%11011111
out (SND_DATA_REG),a out (SND_DATA_REG),a
; silence noise ch ; silence noise ch
ld a,%11111111 ld a,%11111111
out (SND_DATA_REG),a out (SND_DATA_REG),a
ret ret
; Plays the system beep.
Snd_beep: Snd_beep:
; ch1 max volume ; ch1 max volume
ld a,%10010000 ld a,%10010000
@ -48,3 +49,10 @@ Snd_beep:
ld a,%10011111 ld a,%10011111
out (SND_DATA_REG),a out (SND_DATA_REG),a
ret ret
; Sets the attenuation value for a channel
; @param a Channel (0, 1, 2, 3(Noise))
; @param c Attenuation (0 to 16)
; Snd_setAtt:
; cp a, 0