LisaList2

Can you show how your Twiggy drive is connected to your LisaFPGA and the Twiggy breakout board?

Quote from: ried on September 04, 2026, 06:22:55 PMCan you show how your Twiggy drive is connected to your LisaFPGA and the Twiggy breakout board?

I'll try and get that later tonight or tomorrow. I need to put away my real Lisa in order to get my workspace back for the FPGA board. I was just thinking though, I had it connected to the lower connector on the Twiggy adapter board as that's where I had it when testing the other day before trying tonight with my power supply. I had to get a banana plug to test clip cable to hook it up. I'll try connecting to the upper connector and see if my results are any different.



I'll update with photos after further testing.

Yeah, I have had success with the Upper Twiggy connector on the breakout board, but not the Lower Twiggy side.

Quote from: ried on September 04, 2026, 06:22:55 PMCan you show how your Twiggy drive is connected to your LisaFPGA and the Twiggy breakout board?

Here is my configuration. The red stripe is located on pin 1 on all the connectors. I tried the upper Twiggy connector on the breakout board but it didn't make any difference. I connected my scope up to the Motor Data Clock pin 22 and when I turn power on to the board the motor spins for 3-5 seconds before stopping and I see a waveform on the oscilloscope although its not a nice square wave, it's very noisy pulses with a regular interval. I didn't get a picture of that but if anyone wants one I could try and get it this weekend.





In the third photo that is a passive board I made several years ago to more easily probe the signals going to the twiggy drive. That is where I can measure and verify I have 5v, -5v, and 12v on the correct pins. And also to probe any signals with a scope or a logic analyzer.
Ignore the spots for switches, I thought I would make a board with multiple purposes as that was the first board I ordered from PCBWay in China.

I believe the red stripe for the 6-pin cable should face down going to the breakout board, not up. Please double-check those connections very carefully.

https://github.com/alexthecat123/LisaFPGA#twiggy-specific-stuff

Quote from: ried on September 04, 2026, 11:13:36 PMI believe the red stripe for the 6-pin cable should face down going to the breakout board, not up. Please double-check those connections very carefully.

https://github.com/alexthecat123/LisaFPGA#twiggy-specific-stuff

In the photo on Alex's GitHub the red stripe is down on both ends. Mine is up on both ends. It shouldn't matter.

Yes, I understand, as long as the position of the connector is in the lower four holes at each end. Just trying to eliminate variables here.

My motor turns on when the board is powered up but does nothing when a disk is inserted after the OS is booted. Running when the LisaFPGA is powered on shows that the board is getting correct voltages at least or the motor couldn't run. I guess since the power is applied to the Twiggy drive upon power up even before the soft power switch is pressed it differs from a real Lisa where the Twiggy only gets power after the soft switch is pressed.

Quote from: ried on Yesterday at 12:53:08 AMYes, I understand, as long as the position of the connector is in the lower four holes at each end. Just trying to eliminate variables here.

I appreciate that. Yes, both ends are in the bottom four holes of the connector. I'll do more investigating in the next few days.

Separate to Twiggy/FDD matters... I was perusing the LisaFPGA schematic and I notice that the ESProFile and the parallel port appear to be wired separately to the FPGA. This is really interesting since it means that (probably with some FPGA code changes) you could boot from the ESProFile and then have the parallel port appear to be one of the ports on a two-port expansion card. You could use it to copy files to and from a real ProFile, or you could hang a Canon PJ-1080A off of the parallel port and print in colour!

Quote from: stepleton on Yesterday at 01:29:55 PMSeparate to Twiggy/FDD matters... I was perusing the LisaFPGA schematic and I notice that the ESProFile and the parallel port appear to be wired separately to the FPGA. This is really interesting since it means that (probably with some FPGA code changes) you could boot from the ESProFile and then have the parallel port appear to be one of the ports on a two-port expansion card. You could use it to copy files to and from a real ProFile, or you could hang a Canon PJ-1080A off of the parallel port and print in colour!

Yeah, that was a big part of why I chose to do it that way! I'll probably get to implementing the parallel card eventually, but right now a standalone version of ESFloppy is my main priority. I've got some prototype boards coming in the mail, so hopefully it's not too far off from being ready.

Quote from: slewis1962 on September 04, 2026, 11:11:54 PMIn the third photo that is a passive board I made several years ago to more easily probe the signals going to the twiggy drive. That is where I can measure and verify I have 5v, -5v, and 12v on the correct pins. And also to probe any signals with a scope or a logic analyzer.

That breakout board is INCREDIBLY helpful! Could you hook a logic analyzer up to all of the signals that form the Twiggy interface and send me the trace while you insert a disk into the drive? That should help narrow things down a lot.

Quote from: AlexTheCat123 on Yesterday at 05:17:45 PM

Quote from: slewis1962 on September 04, 2026, 11:11:54 PMIn the third photo that is a passive board I made several years ago to more easily probe the signals going to the twiggy drive. That is where I can measure and verify I have 5v, -5v, and 12v on the correct pins. And also to probe any signals with a scope or a logic analyzer.

That breakout board is INCREDIBLY helpful! Could you hook a logic analyzer up to all of the signals that form the Twiggy interface and send me the trace while you insert a disk into the drive? That should help narrow things down a lot.

I'll have to get everything set up. I want to do that on a real Lisa first to get a baseline. The first thing I'm going to do tonight is probe my cables to make sure all the connections are there. My 20 pin cables are from Amazon and my 26 pin cables were made at home. I just assumed everything would be alright and they would work so I never tested them but with my problems I need to verify. I'm also going to connect a 3.5" Lisa drive to make sure my LisaFPGA has no problems. I can't seem to find my Floppy Emu at the moment. It's in a box somewhere.

I have a few updates. First, when attempting to boot into LOS 3 I get the following error:



It makes no sense. It won't even give me the boot menu, it boots straight into this error and that's it. I shut off the LisaFPGA, erased the SD card and reloaded the selctor files, nothing would work. I finally changed the ROM back to the Twiggy ROM, rebooted, and was able to choose my boot image. As it was not the Twiggy image it failed to fully boot. I then changed the ROM back and hit the reset button next to the Lisa soft switch. This worked and booted into LOS 3. The only problem is, once I shut it down again I had to go through that whole process. Any ideas? I'll try it again tomorrow and see if it's still doing that.
I forgot to mention it does that with both the built in ESProfile as well as the stand alone ESProfile.

My second update is once I was fully booted into LOS 3 with an external Lisa 3.5" drive I was able to insert a disk and it read it. So, it seems my FPGA board is ok and is able to talk to a 3.5" drive. I also ohmed out the cables from the end that connects to the LisaFPGA all the way to my board. I'm wondering if the 6 pin cable is not making good contact. I have it seated as far as it will go. It may still be making a poor connection. I'm wondering if I would have better luck with female to female individual hookup wires. I have some in a box in my basement. They might fit a little tighter.

Quote from: slewis1962 on Yesterday at 11:55:19 PMIt won't even give me the boot menu, it boots straight into this error and that's it.

I think this is an issue with Stepleton's selector software (used by the ESProFile) and/or the default values for the PRAM, depending on your point of view.

If you press a key during the self-test, you will see the startup-from menu, and then selecting a startup device works.

If you miss that opportunity, (I surmise) the values in the PRAM look like a default startup device has been selected, but doesn't fully specify which device. So when the selector loads it can't tell which parallel port it was loaded from. You can type the digit 1 and it will proceed normally. If you use a real ProFile, I expect it works normally without this hiccup.

As far as I can tell, the integrity check the ROM does on the PRAM values at startup doesn't catch some of the scrambled permutations, and I suppose the default values in the LisaFPGA match one of these (all zeros perhaps).

I see there is a 93C56 eeprom on the LisaFPGA... perhaps that can be used as actual persistent PRAM?

Otherwise, we should probably come up with a new set of default values to request. IIRC there is another problematic PRAM value that makes the MacWorks XL mouse double-click insanely short, so double-click won't work until one changes the setting in the control panel. Other options may be short RAM test and I suppose startup defaults to the primary parallel port.