delay question

[Nigel Goodwin]

The routine reads the incoming bit (either HIGH or LOW), and sets the Carry bit accordingly. This is then rotated in to the Rcv_Byte GPR, the 'f' at the end of the instruction means to write the result back to Rcv_Byte (a W would mean to write the result back to W).

This is repeated 8 times in a simple loop, to build up the complete 8 bits for the full byte.

 

[wejos]

thanks nigel its making sense to me now

 

[Diver300]

As for software delays, they are far more versatile and often more accurate than using timers - you can adjust software delays to give timing to one instruction cycle, you can't do that with timers.

I have used a mixture of hardware and software to give timing to one cycle, while other code can be executed.

The trick is to wait for the timer to get to an intermediate value, then detect the timing exactly.