Problem with PortB Tris

[timmers]

I have a funny problem with driving PortB.6 as a digital io. (18LF 44K22 PBP 2.6c)
The first 3 flashes work fine using HIGH PORTB.6, but doing the same again using PORTB.6 = 1 doesn't work though the other pins work as expected.
I have looked through the data sheet and can find no clues. Can anyone point me in the right direction?

Tim.

TEMPB		VAR BYTE					'Temporary Byte sized register

STARTUP:	        ANSELA = 0					'ALL DIGITAL INPUTS
			ANSELB = 0
			ANSELC = 0
			ANSELD = 0
			ANSELE = 0
			
			TRISA = %11011100			'PortA ins & outs
			TRISB = %00010000			'PortB ins & outs
			TRISC = %11011110			'PortC ins & outs
			TRISD = %10000000			'PortD ins & outs
			TRISE = %00000100			'PortE ins & outs
			
			FOR TEMPB = 1 TO 3						'ALL LED'S FLASH STARTUP SIGNAL
				PORTB.5 = 1
				HIGH PORTB.6
				PORTB.7 = 1
				PAUSE 200

				PORTB.5 = 0
				LOW PORTB.6
				PORTB.7 = 0
				PAUSE 300
			NEXT TEMPB
			
			FOR TEMPB = 1 TO 3						'ALL LED'S FLASH STARTUP SIGNAL
				PORTB.5 = 1
				PORTB.6 = 1
				PORTB.7 = 1
				PAUSE 200

				PORTB.5 = 0
				PORTB.6 = 0
				PORTB.7 = 0
				PAUSE 300
			NEXT TEMPB
			
			GOTO MAIN

[SteveB]

I don't have an answer, just a quick suggestion to trouble shoot. Try putting another TRISB = %00010000 between the FOR...NEXT loops and see what that does. Also, if you use PORTB.6 = 1...PORTB.6 = 0 in the first loop instead of HIGH...LOW, does it work properly?

[mackrackit]

Try LAT
http://www.picbasic.co.uk/forum/show...057#post110057

[timmers]

Adding an extra TRISb.6 = 0 between loops made no difference.
Changing to LATb.6 = 1 works. Thanks for that. Problem solved.

Interestingly, further down the code is ON INTERRUPT. If I put the PORTb.6 = 1 loop after the ON INTERRUPT statement it works fine???

I usually use DT's instant int's (fantastic by the way) but this programme uses I2CREAD and I2cWRITE and so had to go back to ON INTERRUPT to prevent the timing being upset by the ISR.

[mackrackit]

If I put the PORTb.6 = 1 loop after the ON INTERRUPT statement it works fine???

All I can say is sometimes we get lucky....

Like in the beginning of your code

The first 3 flashes work fine using HIGH PORTB.6

the data latch was clear. That evidently is happening in your ISR.

[SteveB]

Glad to see it get fixed!

this programme uses I2CREAD and I2cWRITE and so had to go back to ON INTERRUPT to prevent the timing being upset by the ISR.

You might look into using the hardware I2C. You'd have to write some routines to deal with the data, but it will work well once you do.

[timmers]

I agree, hardware I2c is the way to go, but thats alot of effort to make it work. The I2cREAD/WRITE work so well outside an interrupt environment.