news@daver.bungi.com (02/07/91)
You'll see Simon's posting saying his PC532 is now working. We've had a big session last night doing assembly/testing on three boards, and we expect to see some more come to life within a few weeks (it's hard finding[making] enough time for hack-sessions). However, one of my boards is being stubborn. When powered up, not much happens. The LEDs don't light, and no traffic goes down the serial line. By exploring with a multimeter, I've convinced myself that the RAM refresh is occurring. At least, I can see the high-order address lines rising and falling. This means that the CPU has executed enough EPROM code to initialise the ICU? Over the next few days I'll be poring over the circuit diagrams and the ROM code in an attempt to isolate the problem, but if anyone can give a suggestion I'd be most grateful! Btw, the ROM is one that was shipped with one of the original PC532 kits. Next weekend we'll have access to a logic analyser, so we'll put our boards side by side and start comparing. The board has 4 Mb of RAM, the parity PAL removed for now, the CPU is firmly in place, etc. "It's a mystery to me".... and it's damn annoying! :-) ___________________________________________________________________________ David Burren (Athos) img Consultants Systems Development (general dogs-body) G.P.O. Box 3304GG Melbourne, VIC 3001 Email: athos@img.uu.oz.au Australia Phone: +61 3 819 4554