'PIC16F876 Who says hardware bug?'
|At 16:22 3/11/99 -0800, you wrote:
Pulling it out of circuit only exasporates the problem even more.
The programme that you provided indicted that you where reading the port
pin then modifing it, this will cause unknown state to be read from the
pin. You must include some form of shadow register for the pin, modify this
then write that out.
Try this: -
xorwf shadow_register,f ;not a good idea as it effects a
ll the bits
goto set low
Dunno why this seems to work cosmic radiation or something
>>And for not working :
>>m015 MOVLW .1
>>00F0 1283 0529 BCF 0x03,RP0
>>00F1 1303 0530 BCF 0x03,RP1
>>00F2 0685 0531 XORWF PORTA,1 This reads PORTA
then XORs that
value. If you take a look at the port structure of the PIC you will see
that reading this point will NOT read what you wrote, but what the pin
sees, note that the driver is disconnected during this phase, hence why you
don't see what you think you see.
>>00F3 0000 0533 NOP
>>00F4 0000 0535 NOP
>>00F5 0000 0537 NOP
>>00F6 0000 0539 NOP
>>00F7 0000 0541 NOP
>>00F8 28EF 0547 GOTO m015
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