;
; PGA2310PA controler with AVR ATtiny26L
;
; ver 1.0 
; by UENO Tomohiro    2004/07/06

.include	"tn26def.inc"

.def	tmp		= R16
.def	vol		= R17
.def	prev_raw_vol 	= R18
.def	prev_vol 	= R19
.def	data_l		= R20
.def	data_r		= R21

.equ	vr		= 0	; portA
.equ	zcen		= 1	; portA
.equ	cs		= 2	; portA
.equ	sdi		= 3	; portA
.equ	sck		= 4	; portA
.equ	mute		= 5	; portA
.equ	select		= 7	; portA

	rjmp	reset	; $000 reset vector
	reti		; $001 EXT_INT0 
	reti		; $002 PIN_CHG 
	reti		; $003 TIMER1 COMPA 
	reti		; $004 TIMER1 COMPB
	reti		; $005 TIMER1 OVF1 
	reti		; $006 TIMER1 OVF0 
	reti		; $007 USI_STRT
	reti		; $008 USI_OVF
	reti		; $009 EE_RDY
	reti		; $00A ANA_COMP
	reti		; $00B ADC

reset:
	ldi	tmp, LOW(RAMEND)
	out	SP,tmp

	; portA initialize
	ldi	tmp,0b11111110	; 5-1:output, 7-6,0:input
	out	DDRA,tmp
	ldi	tmp,0b11011110	; bit 7-6:pullup
	out	PORTA,tmp

	; portB initialize
	ldi	tmp,0b00000000	; bit 7-0 input (no use)
	out	DDRB,tmp
	ldi	tmp,0b11111111	; bit 2-0 pullup
	out	PORTB,tmp

	; AD converter initialize
	ldi	tmp,0b00100000 	; REFS1=0,REFS0=0(AVCC),ADLAR=1(left adjust),convert=ADC0
	out	ADMUX,tmp

	ldi	tmp,0b11100111	; ADEN=1,ADSC=1,ADFR=1(continue),ADIF=0,ADIE=0,ASPS2-0=111
	out	ADCSR,tmp

	sbi	PINA,zcen
	
	ldi	vol,0
	mov	data_r,vol
	mov	data_l,vol
	rcall	write

	ldi	tmp,255
wait_loop:
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	dec	tmp
	brne	wait_loop
	
	sbi	PORTA,mute

	ldi	prev_vol,0
	ldi	prev_raw_vol,0

main_loop:
	ldi	tmp,255
	nop
	nop
	dec	tmp
	brne	PC-3

	in	vol,ADCH

	mov	tmp,vol
	inc	tmp
	cp	tmp,prev_raw_vol
	brlo	PC+6

	mov	tmp,vol
	dec	tmp
	cp	prev_raw_vol,tmp
	brlo	PC+2

	rjmp	main_loop

	mov	prev_raw_vol,vol

	in	tmp,PINA
	bst	tmp,select
	brtc	PC+4
	ldi	ZL,LOW(vol_data_1)
	ldi	ZH,HIGH(vol_data_1)
	rjmp	PC+3
	ldi	ZL,LOW(vol_data_2)
	ldi	ZH,HIGH(vol_data_2)
	lsl	ZL
	rol	ZH	
	ldi	tmp,0
	add	ZL,vol
	adc	ZH,tmp
	lpm	vol,Z
	
	cp	vol,prev_vol
	breq	main_loop
	mov	prev_vol,vol
	mov	data_l,vol
	mov	data_r,vol
	rcall	write

	rjmp	main_loop

write:
	cbi	PORTA,sck
	cbi	PORTA,cs

	ldi	tmp,16
write_loop:
	cbi	PORTA,sdi
	sbrc	data_r,7
	sbi	PORTA,sdi
	sbi	PORTA,sck
	nop
	nop
	nop
	nop
	nop
	nop
	cbi	PORTA,sck
	lsl	data_l
	rol	data_r
	dec	tmp	
	brne	write_loop

	sbi	PORTA,cs
	ret


vol_data_1:
.db	32,32,33,34,34,35,36,36,37,38,38,39,40,40,41,42,42,43,44,44,45,46,46,47,48,48,49,50,50,51,52,52
.db	53,54,54,55,56,56,57,58,58,59,60,60,61,62,62,63,64,64,65,66,66,67,68,68,69,70,70,71,72,72,73,74
.db	74,75,76,76,77,78,78,79,80,80,81,82,82,83,84,84,85,86,86,87,88,88,89,90,90,91,92,92,93,94,94,95
.db	96,96,97,98,98,99,100,100,101,102,102,103,104,104,105,106,106,107,108,108,109,110,110,111,112,112,113,114,114,115,116,116
.db	117,118,118,119,120,120,121,122,122,123,124,124,125,126,126,127,128,128,129,130,130,131,132,132,133,134,134,135,136,136,137,138
.db	138,139,140,140,141,142,142,143,144,144,145,146,146,147,148,148,149,150,150,151,152,152,153,154,154,155,156,156,157,158,158,159
.db	160,160,161,162,162,163,164,164,165,166,166,167,168,168,169,170,170,171,172,172,173,174,174,175,176,176,177,178,178,179,180,180
.db	181,182,182,183,184,184,185,186,186,187,188,188,189,190,190,191,192,192,193,194,194,195,196,196,197,198,198,199,200,200,201,202
vol_data_2:
.db	72,72,73,74,74,75,76,76,77,78,78,79,80,80,81,82,82,83,84,84,85,86,86,87,88,88,89,90,90,91,92,92
.db	93,94,94,95,96,96,97,98,98,99,100,100,101,102,102,103,104,104,105,106,106,107,108,108,109,110,110,111,112,112,113,114
.db	114,115,116,116,117,118,118,119,120,120,121,122,122,123,124,124,125,126,126,127,128,128,129,130,130,131,132,132,133,134,134,135
.db	136,136,137,138,138,139,140,140,141,142,142,143,144,144,145,146,146,147,148,148,149,150,150,151,152,152,153,154,154,155,156,156
.db	157,158,158,159,160,160,161,162,162,163,164,164,165,166,166,167,168,168,169,170,170,171,172,172,173,174,174,175,176,176,177,178
.db	178,179,180,180,181,182,182,183,184,184,185,186,186,187,188,188,189,190,190,191,192,192,193,194,194,195,196,196,197,198,198,199
.db	200,200,201,202,202,203,204,204,205,206,206,207,208,208,209,210,210,211,212,212,213,214,214,215,216,216,217,218,218,219,220,220
.db	221,222,222,223,224,224,225,226,226,227,228,228,229,230,230,231,232,232,233,234,234,235,236,236,237,238,238,239,240,240,241,242