BlueSCSI on Macintosh Portable

[Sideburn]

I am using no special configuration (Mac Plus) and a self made adapter (some pics in the Resources section of the forum).
Virtual drive formatted using HD Toolkit and with HDT driver installed.
I just did a random test, waking it up 10 times in sequence after sleep. Not a single failure, even after two hours sleep.
But sometimes, erratically, when I wake it up from sleep, it just crashes and it automatically reboots.

What I know is that with SCSI2SD it was crashing every single time, fundamentally the reason why I swapped it with BlueSCSI.

I am using the HD0-OpenRetroSCSI-6.0.8-500M.hda pre made image found here: https://mega.nz/folder/8hA3AQCJ#pWUq92L70yDXlogy9lk5Dg/folder/ltAn0Y7Q

Maybe put that on and SD card along with the Mac Plus ini here: https://ini.bluescsi.com/ and see if that causes a delay on your system?

 

[alxlab]

I have BlueSCSI first series installed in my non back lit machine with 5 Mb of RAM. Running 7.5.3.
Before I had a SCSI2SD 5.1 and the machine would systematically crash upon waking up from sleep.
With the BluesSCSI things are much better, still it occasionally crashes. Can’t observe any pattern, though.

I just read this from https://lowendmac.com/1989/mac-portable/

Never use a version of Apple HD SC Setup newer than 7.3.1 (which comes with System 7.0.1) or your Portable will crash while waking from sleep mode.

Sounds like you might have had that issue.

 

[SuperSVGA]

I just did another test, and it seems leaving the SCSI emulator powered externally lets it wake up without issue.

Without the external power when the issue is occurring, jumping to InitSCSI using G 900732 gets it going again, so my guess at the moment is when InitSCSI is initially called during the WakeUp, the SCSI emulator is still powering up and might be in a weird state, causing SCSI to fail to initialize.
I need to see if I can find a non RP2040 based design I have around somewhere to see if that has the same issue. And then probably hook the logic analyzer up to see exactly what it's doing.

 

[Sideburn]

I just did another test, and it seems leaving the SCSI emulator powered externally lets it wake up without issue.

Without the external power when the issue is occurring, jumping to InitSCSI using G 900732 gets it going again, so my guess at the moment is when InitSCSI is initially called during the WakeUp, the SCSI emulator is still powering up and might be in a weird state, causing SCSI to fail to initialize.
I need to see if I can find a non RP2040 based design I have around somewhere to see if that has the same issue. And then probably hook the logic analyzer up to see exactly what it's doing.

Ahh that makes sense. I was thinking earlier of powering the BlueSCSI externally. That won't work as a permanent fix of course since the battery would drain but I could try it here to see if it resolves the issue. Does it need both 5 and 12v?

 

[Sideburn]

I just powered the BlueSCSI with a micro USB to the Pi Pico and sure enough that solved the problem. So we've got a power up timing issue...

 

[SuperSVGA]

Does it need both 5 and 12v?

No, it only needs the 5V.

 

[Sideburn]

No, it only needs the 5V.

Yeah, tested and confirmed. I am seeing the same results as you are. Do you think there's a way to fix and re-flash the pico?

 

[SuperSVGA]

Well, I hooked up my SCSI debug board in between the Portable and the SCSI emulator and somehow just having that connected makes the issue go away. Now I just need to see which component on there is doing it, because the only things connected are a diode, power LEDs, and passive termination that shouldn't be enabled.

 

[Sideburn]

Well, I hooked up my SCSI debug board in between the Portable and the SCSI emulator and somehow just having that connected makes the issue go away. Now I just need to see which component on there is doing it, because the only things connected are a diode, power LEDs, and passive termination that shouldn't be enabled.

Wow. almost seems like it could be voltage / current related...

 

[SuperSVGA]

So after discovering connecting the logic analyzer fixes the issue, it seems like it's something with the SEL line. Putting a capacitive load on it seems to partially resolve the issue.
I put a 10nF capacitor from SEL to ground, and it will wake from sleep after a few minutes just fine. There was one time it didn't work, but I haven't been able to get it to happen again.

 

[Sideburn]

So after discovering connecting the logic analyzer fixes the issue, it seems like it's something with the SEL line. Putting a capacitive load on it seems to partially resolve the issue.
I put a 10nF capacitor from SEL to ground, and it will wake from sleep after a few minutes just fine. There was one time it didn't work, but I haven't been able to get it to happen again.

ok I can try. I need to know which pin to add the cap (select pin) and find a gnd pin to connect to. This is the one I have: https://androda.work/product/bluescsi-v2-desktop/

 

[Sideburn]

Adding it to the 34pin to 50pin adapter would probably be best. Need to find a schematic.

 

[Paolo B]

Sounds like you might have had that issue.

Uh, that’s interesting, thanks for sharing!
Honestly I don’t remember the configuration, I might have used the patched Apple disk formatter. That could explain.

 

[Paolo B]

I am using the HD0-OpenRetroSCSI-6.0.8-500M.hda pre made image found here: https://mega.nz/folder/8hA3AQCJ#pWUq92L70yDXlogy9lk5Dg/folder/ltAn0Y7Q

Maybe put that on and SD card along with the Mac Plus ini here: https://ini.bluescsi.com/ and see if that causes a delay on your system?

I guess the culprit is now identified.
Btw, the adapter I am using is constantly powering the BlueSCSI unit.

 

[Sideburn]

I guess the culprit is now identified.
Btw, the adapter I am using is constantly powering the BlueSCSI unit.

Ahh ok, that confirms why it is working for you. Are you tapped in directly to the battery?

 

[Sideburn]

Anyone know off hand which pins here are SEL and GND?

 

[SuperSVGA]

Here should be ground points and SEL in red:

 

[Sideburn]

Here should be ground points and SEL in red:
View attachment 12759

Awesome thanks. I will put a .01uf cap on it and see how it goes.

 

[Paolo B]

Complete pinout here:

https://tinkerdifferent.com/resources/macintosh-portable-scsi-adapter.38/

(PDF download)

 

[Sideburn]

Complete pinout here:

https://tinkerdifferent.com/resources/macintosh-portable-scsi-adapter.38/

(PDF download)

Thanks, I edited the last reply to you. Was wondering how you went about direct power to your BlueSCSI... did you tap directly into the battery? you have constant power to it even when you shut down?