18F software uart interferes with hardware uart

[burnsy]

Here's and interesting one. I recently made the change from a 16F877 to 18F452. With a little help from this forum, a few port address changes and my whole program ported accross nicely.

However, I have a comms problem on the 18F that doesn't exist on my 16F processor. Too many printf statements stops comms on my hardware uart. I use the onboard hardware uart, with a 485 bus that connects to a bunch of other devices in a vending machine. It is interrupt driven.

Occaissionally, I need to print a receipt. I do this by calling a print receipt function, which uses the #use statement to reassign printif statements to a pin on porta. I have a printer hooked up to this pin. I print the req info to the printer, do another #use statement to put control back to the hardware uart and continue.

As I said this works fine on my 16f877, on many projects. On my 18F452 I can use 21 printf statements and all is fine, if I use 22 or more, my hardare uart doesn't function, from the start. I don't even call the print receipt function once???


Any clues without me posting the code (huge!)? I use pch 3.156.

thanks
_________________
This is the last code change until its ready....

[rwyoung]

Have you tried using named streams instead of fooling around with extra #use statements?
_________________
Rob Young
The Screw-Up Fairy may just visit you but he has crashed on my couch for the last month!

[burnsy]

After your suggestion, I tried streams. I like that idea better (than the multiple #use statements), but didn't change anything. Add one too many printf statements and no comms.. damn it..

I was also able to crash comms by removing some printf statements. ??

thanks for your suggestions
_________________
This is the last code change until its ready....

[Mark]

Maybe its not the number of printf's causing the problem but a particular one.

[burnsy]

Turned out to be the compiler Mark. 3.209 works perfectly

now is there anysuggestions about I2C (grin)...
_________________
This is the last code change until its ready....