Strange Behavior in setting several pin outputs states.

[kappuz]

Yes, I am using your shadow method, but it only works with adding pauses this way:

PORTC.0 = 1
PAUSE 10
PORTC.1 = 1
PAUSE 10
PORTC.2 = 1
PAUSE 10
PORTC.3 = 1

If I remove the pauses, then the thing does not work...

Thank you very much again.

[rmteo]

What if you did it like this?

 ShadowC VAR byte
 ShadowC = PORTC

 ShadowC.0 = 1
 PORTC = ShadowC

 ShadowC.1 = 1
 PORTC = ShadowC

 ShadowC.2 = 1
 PORTC = ShadowC

 ShadowC.3 = 1
 PORTC = ShadowC

[kappuz]

I want to thank you very much.

The problem is resolved, now I am setting the pin output states super fast!

The final working code was the one posted by rmteo, but thank you all really!


ShadowC VAR byte
ShadowC = PORTC

ShadowC.0 = 1
PORTC = ShadowC

ShadowC.1 = 1
PORTC = ShadowC

ShadowC.2 = 1
PORTC = ShadowC

ShadowC.3 = 1
PORTC = ShadowC

[HenrikOlsson]

You can do it even faster by doing it the way Charles originally showed you, (did you REALLY try that and it didn't work?) in other words:

ShadowC VAR BYTE
ShadowC = PortC

ShadowC.0=1
ShadowC.1=1
ShadowC.2=1
ShadowC.3=1

PortC = ShadowC

/Henrik.

[rmteo]

You can do it even faster by doing it the way Charles originally showed you, (did you REALLY try that and it didn't work?) in other words:

ShadowC VAR BYTE
ShadowC = PortC

ShadowC.0=1
ShadowC.1=1
ShadowC.2=1
ShadowC.3=1

PortC = ShadowC

/Henrik.

Even faster would be this way - but obviously the OP did not try it the way Charles described.

ShadowC VAR BYTE
ShadowC = PortC

ShadowC.0 = $F

PortC = ShadowC

[rmteo]

Sorry for the typo - and the inability to edit a post.

ShadowC VAR BYTE 
ShadowC = PortC  

ShadowC = $f 

PortC = ShadowC

[HenrikOlsson]

Hi,

Even faster would be this way - but obviously the OP did not try it the way Charles described.

Not really because then the top four bits will be 0 which they might not have been when PortC was read. And IF the top four bits doesn't matter then I see no reason for not simply writing to PortC directly, ie PortC = $F which would make THIS particular example even faster....

However, I suspect that setting the low four bits to 1 are just an example. Using bitwise AND/OR could also work but I'm not sure it's faster than simply flipping the four bits in ShadowC and then writing it to the port.

/Henrik.