LisaList2

I don't have a scope, but am happy to give it a try. What kind of scope should I use (any suggestions?) and how would I probe that particular signal?

When I received my LisaFPGA board the first thing I wanted to try was get it connected to the modern internet.  I was hoping to use Localtalk (MacIP), but then I learned that the hardware for Localtalk was not implemented on LisaFPGA. 

So for plan "B", I am using a PPP connection over RS232 at 56K baud.  I am running MW+II, System 6.08, MacTCP, MacPPP.  Connecting to a PPP server running on a Raspberry Pi 3.

With this setup I can run NCSA telnet and have multiple terminal sessions running at the same time.  NCSA telnet also supports FTP file transfers. The TCP/IP stack is running directly on the LisaFPGA hardware.  Works great!

Rick

Quote from: ried on August 29, 2026, 10:58:29 AMI don't have a scope, but am happy to give it a try. What kind of scope should I use (any suggestions?) and how would I probe that particular signal?

If you've got a logic analyzer, that would work too. I wouldn't want you to buy a whole scope just for this, especially since the problem is almost certainly my fault not yours! You'd want to probe the PWM line on the Sony floppy connector (J3), which happens to carry MT0 when it's in Twiggy mode. PWM is pin 20 on the floppy connector, so if you find the text on the PCB that reads J3, it's the connector pin that's immediately above there, on the inner column of pins.

I would just probe it myself on my board, but the Twiggy floppy controller won't emit pulses on MT unless it detects a disk in place, and since I don't have any real Twiggy drives, I have no good way to spoof disk in place without screwing up the other SNS registers too.

I've looked over my code again and I don't see any problems, so it's got to be something stupid that I'm overlooking. Just to rule out the drive, can you swap things around and plug your upper drive into the lower connector and your lower drive into the upper connector and see if the problem switches drives? And @sigma7, if you could confirm whether or not both of your Twiggies spin with the new LisaFPGA code, that would be great too.

Quote from: Lisa2 on Yesterday at 10:43:23 PMWhen I received my LisaFPGA board the first thing I wanted to try was get it connected to the modern internet.  I was hoping to use Localtalk (MacIP), but then I learned that the hardware for Localtalk was not implemented on LisaFPGA. 

Yeah, unfortunately I couldn't find a good modern source for the differential driver ICs that you need. So I left that functionality off the board, under the assumption that practically nobody would actually use it. Clearly I was wrong; sorry!!!

As a side note, how did you get your PFG working in the SCC socket? Did you revert to my old code that uses the external SCC, or did you modify the new code to make it switchable between internal/external? Either way, it's really cool to see someone use a PFG with the board; I think you're the first person besides me to actually try it!