pt2257.asm

pt2257 control code.

vol_tbl:                        
                addam   pc,1    ;vol_point
                retla   00h     ;   0
                retla   03h     ;   1
                retla   06h     ;   2
                retla   09h     ;   3
                retla   12h     ;   4
                retla   15h     ;   5
                retla   18h     ;   6
                retla   21h     ;   7
                retla   24h     ;   8
                retla   27h     ;   9
                retla   30h     ;   10
                retla   32h     ;   11
                retla   34h     ;   12
                retla   36h     ;   13
                retla   38h     ;   14
                retla   40h     ;   15
                retla   42h     ;   16
                retla   44h     ;   17
                retla   46h     ;   18
                retla   48h     ;   19
                retla   50h     ;   20
                retla   51h     ;   21
                retla   52h     ;   22
                retla   53h     ;   23
                retla   54h     ;   24
                retla   55h     ;   25
                retla   56h     ;   26
                retla   57h     ;   27
                retla   58h     ;   28
                retla   59h     ;   29
                retla   60h     ;   30
                retla   61h     ;   31
                retla   62h     ;   32
                retla   63h     ;   33
                retla   64h     ;   34
                retla   65h     ;   35
                retla   66h     ;   36
                retla   67h     ;   37
                retla   68h     ;   38
                retla   69h     ;   39
                retla   70h     ;   40
                retla   71h     ;   41
                retla   72h     ;   42
                retla   73h     ;   43
                retla   74h     ;   44
                retla   75h     ;   45
                retla   76h     ;   46
                retla   77h     ;   47
                retla   78h     ;   48
                retla   79h     ;   49

		;
		;
		;
		;

;----------------------------------------
set_vol:
                movam   vol_point
;start bit.
                bsm     _sda
                lcall   delay7us
                bsm     _scl
                lcall   delay7us
                bcm     _sda
                lcall   delay7us
                bcm     _scl
;Set PT2257's Address.
                movla   88h
                lcall   send_i2c_dat
                lcall   i2c_ack
;set -10db.
                movm    vol_point,0
                lcall   vol_tbl
                movam   tmp0
                swapm   tmp0,0
                andla   0fh
                iorla   b'11100000'
                lcall   send_i2c_dat
                lcall   i2c_ack
;set -1db:
                movm    vol_point,0
                lcall   vol_tbl
                andla   0fh
                iorla   b'11010000'
                lcall   send_i2c_dat
                lcall   i2c_ack
stop:
                bcm     _sda
                nop
                bsm     _scl
                lcall   delay7us
                bsm     _sda
                lcall   delay7us
                ret
send_i2c_dat:           
                movam   tmp0
                movla   .8
                movam   tmp1
send_i2c_dat_loop:
                rlm     tmp0,1
                bsm     _sda
                btmss   _c
                bcm     _sda
                nop
                bsm     _scl
                lcall   delay5us
                bcm     _scl
                decmsz  tmp1,1
                lgoto   send_i2c_dat_loop
                ret
i2c_ack:
                bsm     _sda
                movla   b'11000101'
                iodir   iodir_b
                bsm     _scl
                lcall   delay5us
                bcm     _scl
                movla   b'11000001'
                iodir   iodir_b
                lcall   delay5us
                ret