any PIC programmers in the house?

Phil_aka_Pip

PIC16F877 to be precise. MPLABX IDE with MPASM assembler. serial i/o funnies.

before you C++ or Java people start, no I can't rewrite the application in a "modern" language, and it wouldn't do any good if I could.

bertie

dont you mean "PIC software engineers"

Phil_aka_Pip

yes I suppose so. The "programmer" is a USB device called a PicKit3 and it controls the PIC as told to by the IDE

btw this particular "funny" has been resolved, although I'm not sure why the "solution" works. You received a message (RS485 bus) and are replying to it. Replying to it immediately causes the outgoing message to be garbled (although the TX buffer, and the trace buffer that I put in in an attempt to diagnose this) contain exactly what I'd expect. but if you set up a timer, and delay the TX by 2 clock ticks (ie you don't turn on TX interrupts until the timer has gone off), then everything works fine. maybe the RS485 h/w needs more time to react to being told "You're not receiving now, you're transmitting". Only happens with some messages, I guess its the ones that don't take long to process.

Misterg

A bit. 16F87, though... a while ago... with MPASM. I did discover an un-documented 'feature' regarding offset addresses if that is in any way relevant.

Phil_aka_Pip

@Misterg so you've seen these odd little device too, eh? weird aren't they!

Misterg

I liked them! Quite an elegant instruction set. Used the 16F87 for a few projects.

What ails you?

Phil_aka_Pip

They certainly have their uses. It's the segmented address space I dislike, but then I always have disliked segmented address space ever since the PDP-8, but especially on 8086s - yuk!

As per earlier post, I think I've got round the problem I was having, which appears to be a timing issue.

The present job is an "i/o board" which reads 8 digital inputs and writes 8 digital outputs according to messages sent on an RS485 bus. What did you do with your PICs?

Misterg

Phil_aka_Pip said:

What did you do with your PICs?

Interpreting data from a line-scan camera for industrial measurement (parallel in/out + synchronising & timing);
Running a fatigue test rig (with 3 digit display & presettable counter, all from the PIC);
Various other hobby stuff including a 3 axis camera mount with R/C servos...

Brought up on 6502s