'20x-2 picaxe

  High c.2
  High c.0
  
SYMBOL control	= b0 	 			; Used here for control bits DONT use for else 
SYMBOL mask		= bit0			; Mask word for the shiftout proceedure
SYMBOL index	= b1				; Bit counter for shifting data to SOMO 14D
SYMBOL track	= w1				; Pointer to the required track file
SYMBOL dta		= w2				; Data to send is a word(16-bit) value

SYMBOL MSB		= $8000			; Mask for the Most Significant Bit = bit 16

SYMBOL sda		= c.0				; Serial data output is on pin3
SYMBOL scl		= c.2				; Serial clock output is on pin2
SYMBOL busy		= pinC.6			; Busy line back from SOMO 14D

Init:
	high scl					; Set clock to high idle state
	wait 5					; Allow everything to start before sending commands

'goto Main

loop1:
'b8 = 11
b10 = 0
IRIN b.6, b8
'b8 = 11
      if b8 = 0 then t1b 'button1=0
	if b8 = 1 then t1    '2
	if b8 = 2 then t1
	if b8 = 3 then t1
	if b8 = 4 then t1
	if b8 = 5 then t1
	if b8 = 6 then t1
	if b8 = 7 then t1
	if b8 = 8 then t1
	if b8 = 9 then t1a
	'debug b8
goto loop1


loop2:
t1b:
b8 = 1
b10 = 1
goto t1

t1a:
b8 = 0

t1:
'b12 = 55
pause 500
'b13 = 77

irin [2000,loop1],b.6,b9

      if b9 = 0 then t2 'button1=0
	if b9 = 1 then t2    '2
	if b9 = 2 then t2
	if b9 = 3 then t2
	if b9 = 4 then t2
	if b9 = 5 then t2
	if b9 = 6 then t2
	if b9 = 7 then t2
	if b9 = 8 then t2
	if b9 = 9 then t3a
goto loop2


t2:
if b8 = 0 then t3
if b8 = b10 then t4
b8 = b8 + 1

t4:
b8 = b8 * 10
t3:
b10 = b8 + b9 + 1
dta = b8 + b9 + 1
b12 = dta
goto t5

t3a:
b8 = b8 + 1
b8 = b8 * 10
b10 = b8
dta = b8 + b9 + 1
b12 = dta
goto t5

t5:
'debug
gosub send1
pause 1000
goto loop1


send1:
gosub send2
GOSUB Hold
return




'send data
;
Send2:
	LOW scl					; Pull clock-line low for a start
	PAUSE 2					; Start-bit time >= 2msec to indicate a start of command
	FOR index = 1 TO 16			; loop for each of 16 bits of filename/number
  		mask = dta AND MSB / MSB 	; mask out the most sign. bit to find if next bit is 1 or 0
		LOW sda
		IF mask = 0 THEN SkipMSB	; check if current data bit is "0" and skip if it is a zero
		HIGH sda				; set data line highonly if the data bit is a "1" 
SkipMSB: 
		IF index = 16 THEN Skip16th	; Skip here as 16th bit is clocked out at the end
		
  		PULSOUT scl,20			; Create 200usec clock pulse for the current data bit
   		dta = dta * 2			; shift data one bit to left read to check for the next bit to shift out

Skip16th:
	NEXT index					; Go back for the next bit till all 16 bits of data presented to SOMO module
	HIGH scl					; Pull clock-line high which also clocks out the 16th data bit
	PAUSE 2					; End-bit minimum time >= 2msec for STOP indication
	RETURN


'hold till file finishes
Hold:
 	PAUSE 30				; Need to wait briefly as it seemingly takes ~5-7msec for the busy line to go high = busy
 	IF busy = 1 THEN Hold
	PAUSE 30				; Need to wait briefly as it seemingly takes ~5-7msec after busy released before SOMO ready for new instruction
	RETURN