Init Code and fast_io()

[bdavis]

I haven't seen an example of how to initialize the ports if using "#pragma use fast_io()" or other ports with set_tris_x() in regard to ordering with port initialization of the pragma's such.

Do you use #pragma use rs232 () & #use i2c(), then fast_io(), then setup_ports( NO_ANALOGS ), then set output ports to a value, then set_tris_x() ?

I want to use the standard I2C and UART support too, and am concerned about trashing the output states for the pins for RX, TX, SDA, SCL.
I would like to use fast_io() on all ports.

[PCM programmer]

Here's an example:
http://smg.media.mit.edu/projects/CurlyCart/code/curlycrt-c.html

[bdavis]

Thanks for the reply PCM I was beginning to think there was no hope

The example was careful to not use fast_io() on port C (where I2C/RX/TX are used ).

I did see that they did use:
fast_io()
then set_tris_x(),
then setup_ports( NO_ANALOGS )
then then set output ports to a value

I think I will omit the fast_io() on port c until I have enough time for proper testing and looking at various listing files. I may later just control the I2C and UART directly, and then I should know exactly what is going on, but I would give up portability and any errata corrected by the compiler.

By the way - unrelated, but found that xor'ing a bit takes 10 instructions, while doing a if/else to flip it only takes 5 instructions. I just need to get comfortable with knowing what the compiler is doing well, and what it does poorly...

I hope CCS gives you freebies for all the help you give people on this forum.

Thanks again!

[Ttelmah]

[bdavis]

Thanks Ttelmah

That helps, and eliminates many worries about not knowing for sure what the compiler wants for the TRIS. I didn't know about the different setups for TRIS for the UART on different chips, so thanks for that too!