PIC 16F627A Programming problem

I am using the chip pic 16f627a

setting PORTA to inputs & PORTB to outputs >>


giving a high input to PORTA,0 >>

I used the btfsc(bit test skip if zero instruction) .. and the tested pin is set to '1' .. so the program shoudn't skip the ****** line


My problem is that the program skips the ****** instruction ,, and goes to the $$$$$$ instruction .. although the tested pin is set to high '1'

If any one knows where is the fault .. I am so gratefull

The pins of PORTA are configured as inputs.
Try this:
and see what happens.

eng1 said:

The pins of PORTA are configured as inputs.
Try this:

Code:

movlw 0x00
movwf TRISA

and see what happens.

Click to expand...

Do you mean that if the pin is set to input .. Then I can't assign it to high or low ??

If I'm not mistaken, pins set as inputs have their bits set according to the incoming voltage level with VDD=Set and VSS=Unset. Don't forget to turn off the comparators to enable digital input.

mas said:

Do you mean that if the pin is set to input .. Then I can't assign it to high or low ??

Click to expand...

If you want to set or clear a bit of PORTA in software, that pin is an output by definition.

When a pin is configured as an input you can read its value, which depends on the applied voltage, as TekNoir said.

I guess you're trying to emulate a switch. If so, you configured PORTA correctly, but the last bsf instruction makes no sense.

yes, I was trying to simulate

I will use a hardware circuit to test the program instead of the simulator

Thanks a lot guys

It is possible to apply a 'stimulus' with the simulator, but it's simple to add a switch with a pull-up resistor (external or internal) to your circuit.

Have fun