PIC Question

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You're going to have to give more descriptive information than that. Source code (the real thing cut and pasted, not re-typed) would help.

Below is a snip of my code, the pulse generator routine. I am using a PIC16C63A witch has an internal UART. I am presently talking @ 2400 baud, 8n1. I am using a terminal program to comunicate to the pic through an MAX233 chip. My UART receive routine is through an interupt, it also echoes back the received data. Three bytes are sent, byte one will be used elsewhere in my program. Bytes 2 & 3 (recuse2, recuse3) are copied to "Multbuf & Addbuf" in the routine below. My variables are all equated to RAM (20h - 30h). When I run it, I get the bytes echoed back as expected, the oscilator outputs around 300HZ, which tells me that my two buffers are not getting the data from recuse (2&3). They seem to be stuck at "ffh". I'm probably missing something basic, but I just don't see it. Any ideas?

Go bsf porta,1 ;toggel porta,1 - pulse output call Loadbuf bcf porta,1 call Loadbuf goto Go Loadbuf movf recuse2,w movwf Multbuf movf recuse3,w movwf Addbuf Again Decfsz Multbuf ;waste some time goto Delay goto Addtime Delay movlw 02 movwf Times More Decfsz Times goto More goto Again Addtime Decfsz Addbuf goTo Addtime return

Dunno about the 16C63A but a couple of others I've built with serial links have needed (ater much f****** about) ...

RCSTA.CREN = 0 'Clear any overrun errors. Reset UART. This is critical ! RCSTA.CREN = 1 '

Prevents a total UART lockup. Needs to be an intrinsic part of the listening or interrupt loop.

Thanks, John. I do have that in my code... I may just add a look-up table and use relative addressing. I was hoping someone could see why this won't work, it would have worked better for me.

I missed they'd been "echoed". The code seems to fully decrement the 2 recuse regs ok. Maybe the recuse regs are not being loaded in the first place. john

me.

No, they are loaded. I use the recuse regs in my "echo" routine, all three bytes are returned correctly.