How can I speed this code up? SHIFTOUT is slowing it down and I need a faster way.

[wolwil]

I think what is slowing this down is the SHIFTOUT.

I am running a 16f88 @ 16MHz and I need to know the fastest way to get through this loop:

LOOP:
	FOR DATA = 4095 to 0 step -1
    		GOSUB SUB1
	    	GOSUB SUB2
	NEXT
	FOR DATA = 0 to 4095 step 1
    		GOSUB SUB1
    		GOSUB SUB2
	NEXT
GOTO LOOP

SUB1:
	FOR C1 = 0 TO 15
    		shiftout dpin,clk,1,[DATA]
	NEXT
    	PORTB = %00100000 
    	PORTB = %00000000  
RETURN

SUB2:
	PORTB = %00000100 
	PORTB = %00000000 
	FOR C3 = 0 TO 4095
    		PORTA = %00001000
    		PORTA = %00000000
	NEXT
RETURN

[mackrackit]

131,072 SHIFTOUTs in that loop and it is shifting the same value 15 times, getting another value and shifting that 15 times, again ,again.... That will tale some time.

Unless I am looking at it cross eyed...

Is the above really what you want to do?

[wolwil]

131,072 SHIFTOUTs in that loop and it is shifting the same value 15 times, getting another value and shifting that 15 times, again ,again.... That will tale some time.

Unless I am looking at it cross eyed...

Is the above really what you want to do?

Yes but not 15 times 16 times and really its not all that bad if I would be able to have it shifting say at 1MHz or more

[mackrackit]

I wonder if SHIFTING all 16 values at once would be faster than looping? Darn zeros

shiftout dpin,clk,1,[DATA,DATA,DATA,DATA,DATA,...]

[wolwil]

I wonder if SHIFTING all 16 values at once would be faster than looping? Darn zeros

shiftout dpin,clk,1,[DATA,DATA,DATA,DATA,DATA,...]

I dunno let me try it...

[wolwil]

Nope The Same

The part that is slow is going from SUB1 to SUB2 not the looping through them 4096 times

I just tried taking out the GOSUB's and still the same thing