Using BitData Types and Variables in PIC18F using Hi-tech Compiler 9.51(PICC-18)

[tarun172]

All,
     I was handed over an old code makes use of bit data types, registers and bit variables. This code base makes extensive use of bit variables. Recently, I came across a suspected bug in this code base. I traced this issue back to one of the bits in register. The bit sets (instead of clearing) upon power cycle causing this issue to occur. At-least, that what I am suspecting. It is pretty repeatable across other devices, old and new. I am using standard hi-tech compiler version 9.50. Reading through user manual, section 3.4.2 and 3.4.3, I am not able to find exact root cause. Why that particular bit? Why only in power up?Is there a particular way of handling these registers and bit during code compilation? Do you normally specify a memory location during compilation?

Regards,
Tarun S

[Bruce Abbott]

I am using standard hi-tech compiler version 9.50.

In the thread title you say 9.51. Which is it?

The bit sets (instead of clearing) upon power cycle causing this issue to occur. At-least, that what I am suspecting.

Why do you suspect this?

Reading through user manual, section 3.4.2 and 3.4.3, I am not able to find exact root cause. Why that particular bit? Why only in power up?

Which bit? Can you show us the code that sets/clears it?

Is there a particular way of handling these registers and bit during code compilation? Do you normally specify a memory location during compilation?

The hardware bits are defined in the header file of the selected MCU, so you should not have to specify their memory locations.