PIC's ports individual bits manipulation - how to?

[SteveB]

How about something simple, like:

PORTA.0 = Digit.0
PORTA.1 = Digit.1
PORTA.2 = Digit.2
PORTA.3 = Digit.3

HTH,
SteveB

[flotulopex]

I just made this piece of code as test.

MYPORT  var PORTA
Loop    var BYTE
PORTA.0 = MYport.0
PORTA.1 = MYport.1
PORTA.2 = MYport.2
PORTA.3 = MYport.3

PORTA.6 = 1 'Test to check port's state change in simulator...

Start:
    for LOOP = 0 to 3
        myport.0[Loop] = 1  'High
        myport.0[loop] = 0  'Low
    next
    goto start
END

It works except the PORTA.6 will change it's status from 1 to 0 when the firt loop will be executed.

[skimask]

I think you've got the variable declarations backwards.
Try myport.0 = porta.0, etc. instead of the way you have it.

[mister_e]

this won't work indeed... and you make it too complicated for what it need to be.

Start:
    for LOOP = 0 to 3
        PORTA.0[Loop] = 1  'High
        PAUSE 500
        PORTA.0[loop] = 0  'Low
    next
    goto start
END

MyPORT.0=PORTA.0 will work only once, If you want to alias a variable bit to a PORT bit... it's an all different story..

[flotulopex]

I've attached two pictures about what I can see.

The first picture "Before Loop Start" shows that my PORTA.0 to 3 are set to "1". This is because I need them to be at this state before the main loop starts (driving CA Leds).

I did the same for PORTA.6 (=1) just for testing purpose. PORTA.6 will be used for something else in my program if I can handle the actual problem.

When I start the execution of the program, PORTA.6 goes to "0" witch is unwanted here.

Mister_E you're right, using DCD will modify all ports.... Was not a good idea on my side. Thank you for making me aware.

[mister_e]

I should have see it first... You must set the TRIS register, unless those pin are set as input.

MYPORT  var PORTB
Loop    var BYTE
TRISB=0
PORTB.6 = 1 'Test to check port's state change in simulator...

Start:
    for LOOP = 0 to 3
        myport.0[Loop] = 1  'High
        PAUSE 500
        myport.0[loop] = 0  'Low
    next
    goto start
END

[skimask]

I've attached two pictures about what I can see.

The first picture "Before Loop Start" shows that my PORTA.0 to 3 are set to "1". This is because I need them to be at this state before the main loop starts (driving CA Leds).

I did the same for PORTA.6 (=1) just for testing purpose. PORTA.6 will be used for something else in my program if I can handle the actual problem.

When I start the execution of the program, PORTA.6 goes to "0" witch is unwanted here.

Mister_E you're right, using DCD will modify all ports.... Was not a good idea on my side. Thank you for making me aware.

Looks like it might be a bug in the simulator. PortA.6 on the F88 is also OSC2/CLKO. I may have missed something, ya never know. Try it on the real thing and see what happens.

[mister_e]

Never mind.. misread the original code...

[flotulopex]

You may be right!

I just noticed that, using an additional microcontroler view in the simulator, the port doesn't change.

So I'm going to make it in "real".

Another thing; I have declared PORTA.6 as an Input (TRISA = %11110000). When I change this to an Output (TRISA = %10110000), the port will keep it's status as it should be.

Unfortunalety, I will need it as an Input.

I'll go back to my breadboard....

[skimask]

You may be right!

I just noticed that, using an additional microcontroler view in the simulator, the port doesn't change.

So I'm going to make it in "real".

Another thing; I have declared PORTA.6 as an Input (TRISA = %11110000). When I change this to an Output (TRISA = %10110000), the port will keep it's status as it should be.

Unfortunalety, I will need it as an Input.

I'll go back to my breadboard....

Actually, I believe I heard both mister_e and DT both say that they don't trust simulators one bit.
However, I trust the Microchip simulator almost implicitly. Why don't you try running your code on that and keeping an eye on the port values?