A Lisa Inside An FPGA

[stepleton]

Great to see this, but 37 watts is quite a draw! I'm glad to know that this is what's needed.

[slewis1962]

Great to see this, but 37 watts is quite a draw! I'm glad to know that this is what's needed.

I'm not sure what exact conditions caused the 7.5 amps the other day. I had two disks in just like in this video but it didn't get that high. Unless I just happened to catch the peak that day. I imagine a data logger of some kind could give a more accurate representation of what's normal.

[AlexTheCat123]

It's great to see both drives working! That's some pretty crazy power consumption though. When I designed the board, I was guessing about 2A max when the drives were active (spindle on and seeking), so 7.5A is absolutely crazy. To be fair though, I had no way of knowing given that I don't have any Twiggies myself!

[ried]

That's great!!! One drive confirmed to be fully-working. I wonder what's going wrong with the lower drive though? You are running the latest firmware that's supposed to fix the bug, right?

I jumped back into this today, suspecting that the four-pin TWIG port on the board and the AUX IN on the breakout board might not be making good connections via that 6-pin cable. I bent the prongs further up on each and, sure enough, now the lower drive's spindle motor spins just fine.

[slewis1962]

I've got a 2 part question. Has anyone successfully initialized a "new" Twiggy disk on their LisaFPGA board? I made a new disk today and tried to initialize it but it failed. I then booted into service mode and attempted to do a format which failed. I should also explain that I have several disks which I initialized or formatted between 14 and 24 years ago that would not read under the LisaFPGA board. I then tried to format them from service mode and was unsuccessful.

So today after the failures I pulled out my real Lisa 1, booted into LOS 1.0, and tried to initialize my new Twiggy disk. I was unsuccessful there also. But when I booted into service mode I was able to successfully format a disk and then LOS 1.0 was able to mount it. I then pulled out the other disks which failed under the LisaFPGA board and several of them failed under a real Lisa also. One was able to format but when I booted into LOS it said the disk was damaged but was unable to repair it and I didn't get the option to initialize it. I'm just wondering what could be different between the real Lisa and the LisaFPGA board in regards to service mode and formatting disks.

The second question is, I'm wondering if the error code I get in service mode, error 15 unable to verify, is because it is having issues with an underlying format or underlying data already on the disk which is interfering with the format or initialization. Has anyone used a bulk tape eraser on a Twiggy disk? I saw a video in the last year or so on "Adrian's digital basement" where he used a bulk eraser to "fix" some diskettes, 3.5" not Twiggy, that wouldn't format. I'm considering getting one off of ebay but thought I would ask the list first in case anyone has any experience in that area.

Thanks in advance.

[sigma7]

Has anyone used a bulk tape eraser on a Twiggy disk?

BLU has a "zero disk" function that writes nothings over the entire disk, "effectively un-formatting it".

Dunno if it would help in this case. I'd try it on the real Lisa first. ymmv

[slewis1962]

Has anyone used a bulk tape eraser on a Twiggy disk?

BLU has a "zero disk" function that writes nothings over the entire disk, "effectively un-formatting it".

Dunno if it would help in this case. I'd try it on the real Lisa first. ymmv

I'll have to try that first. My real Lisa is still set up so I don't have to get it out again.