Mike, I can't speak directly to your parallel port problem, but I can say I'm having problems controlling a CMOS Si570 with a Propeller microcontroller (haven't tried LVDS yet). No matter how much I shield, bypass, and insert RF chokes; at certain frequencies RF from the Si570 is clobbering the microcontroller and/or serial LCD. This is especially the case when I connect the Si570's RF to my counter or scope. I have the Si570 on a WB6DHW board in a metal enclosure too! I'm going to put the microcontroller in a separate metal enclosure as well.
I looked at Guido's parallel port interface, it seems prone to ground loops. I would use high-speed opto-isolators with logic-level interfaces (from NEC perhaps) or maybe a voltage translator (NXP GTL2002 perhaps). Let us know what you find out. David --- In [email protected], MIke mustang <[EMAIL PROTECTED]> wrote: > > Guys, > I just spent 2 days trying to trouble shoot a weird > problem that I can not figure out. It started when I > modified an Xtall for computer control via the printer > port. All I did was make up the cable using the > BS170's and pulled the PIC and plugged the wires into > the socket in pins 8 for ground and pins 2 and 3. The > Xtall worked perfect with PowerSDR and si570.exe. The > only problem was the SI570 in the Xtall was the LDVS > version and I knew it would not drive the Softrock > directly so I ordered a CMOS version. I removed the > LDVS (was not fun) and CAREFULLY soldered in the CMOS > version. The CMOS version worked with the PIC so I > removed the PIC and plugged in the printer port > interface wires and it did not work at all. I tried > changing the pull ups to 10 k and adding the OE > (output enable) wired to 3 v still nothing. Then in > total desperation I removed the CMOS (not fun again) > and soldered in the LDVS version and everything is > working once again...am I missing something? > > thanks for your help > > Mike WA3O >
