Post by thread:Parallel Port and 17C42

Dear All, Thanks to Antti and Wolfram for their heplful suggestions. I have since got the port working back at home. There was I fault on the I/O card which became apparent when gibberish came out my printers. I replaced the card and my code works fine. But - here at Uni, I still have the problem. The only differences between my PC at home and the one here is that I run Win95 at home while it's Win3.11 here and the Uni computer's on a Novell Network (4.02?). Anybody got any further suggestions. Also, I've got a 17C42 which I'm running in microprocessor mode with a couple of 28C64s. My problem is that I can't seem to write to port_a or port_b. I've run the code in MPLAB, and nothing happens. Here's an quick bite: ......... init clrf porta ;clear port_a start movlw 00h ;move 00h to w movwf porta ;move 00h to port_a call delay ;call delay sub movlw 04h ;move 04h to w movwf porta ;move 04h to port_a call delay ;call delay sub .......... I know that you're not supposed to use bit read-modify-write instructions on port_a, but should 'movwf porta' not work? There isn't a data direction register for port_a, it's intelligent. Cheers. J.W. ----------------------------------------------------------------- Johnnie Walker MSc Digital Systems Engineering Heriot-Watt University email: spam_OUTceejbcwTakeThisOuTcee.hw.ac.uk .....ceejbwKILLspam@spam@pp.hw.ac.uk ceejbwKILLspamtorduff.hw.ac.uk www: http://www.cee.hw.ac.uk/~ceejbcw tel: (0131) 343 2864 -----------------------------------------------------------------