SD2IEC disk swap pinout and switch wiring and firmware

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Barry Nelson

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Jan 10, 2015, 3:05:32 PM1/10/15
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I have an SD2IEC that looks like the picture below. I am looking for information on how and where to wire the disk swap switches, and also which firmware this device uses, sw1, sw2, or larsp. The device functions fine, but I am currently not able to swap disk images except through the file browser. Another issue I have is getting my C128 to boot CP/M from this device. Any information about this would be appreciated.

Jorge

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Jan 10, 2015, 5:08:28 PM1/10/15
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I have the same problem Triste
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RETRO Innovations

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Jan 10, 2015, 5:36:50 PM1/10/15
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On 1/10/2015 4:08 PM, Jorge wrote:
I have the same problem Triste
OK, disclosure:

This forum is for the uIEC, which is a specific hardware solution that uses the sd2iec firmware.  I just wanted to start there, so folks read the rest with that in mind.

I am sure there are various ways to determine the firmware version, but here are two ways:

No PCB tracing needed, but assumes a working bootloader:
  • download a nightly from here http://www.sd2iec.de/nightlies/
  • extract all the binaries
  • put one of the binaries onto a blank SD card (I know this HW is not the uIEC or uIEC3 versions, so try sw1 or sw2 first.
  • reboot the SD2IEC
  • if the unit starts blinking, the unit is the hardware variant matching the firmware on the card
  • If not, clean off the SD card, put another single file on there, and try again.
  • If found, you can keep the nightly (caveat emptor on any bugs), or dload a 0.10.0 and reflash the unit back to the newest release

If none work, or if you'd prefer not to redo the firmware on your unit

JIm

Ingo Korb

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Jan 10, 2015, 6:58:57 PM1/10/15
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Barry Nelson <star...@gmail.com> writes:

> I have an SD2IEC that looks like the picture below. I am looking for
> information on how and where to wire the disk swap switches, and also which
> firmware this device uses, sw1, sw2, or larsp.

My usual advice in this case is "Ask the seller". There are lots of
clones on the market and there is probably nobody in the world who knows
these details for every one of them. Whoever designed that board should
know the answers though.

If you just want to update the firmware, you do not need to know which
of the versions is the correct one for your board - the bootloader
should know that and it completely ignores any files that are for a
different hardware. If your board lacks such a bootloader, it is broken
and should be returned to the seller for repair or refund.

And if you still want to know that little detail, ask the software that
is running on it:

10 open 1,8,15,"x?"
20 get#1,a$
30 print a$;
40 if st=0 then 20
50 close 1

> Another issue I have is getting my C128 to boot CP/M from this
> device. Any information about this would be appreciated.

Another issue I have with your question is that you provide no details
about what you did when you made this observation. More details would be
appreciated. ;)

-i 'and as Jim said: Technically this is a uIEC-only list' k

Barry Nelson

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Jan 12, 2015, 10:27:17 PM1/12/15
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I have found some information I will share with others as people have replied saying they have the same board…

This board appears to run the "sw2" software variant. The pin outs I have obtained are shown in the image below…

As to booting CP/M, I have found the following…

I can boot D64 and D71 CP/M images but not D81. This seems related to a short coming in all the SD2IEC variants, including the uiec and this one, a lack of support for SRQ/fast serial support in the 1581 emulation. This article describes the issue, and references a patch for CP/M but does not have a link to it. <µIEC Users Discussion Group › SRQ/Fast Serial Support>

From the thread, it appears that CP/M insists on running a 1581 in fast serial mode, and will not boot work if the fast serial support check fails, which it does on a SD2IEC device since it is not supported.

If anyone else has information about this, please share it, I would like to get my CP/M D81 images working. I would not mind patching the CP/M system files as a solution.

Ingo Korb

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Jan 13, 2015, 1:25:25 PM1/13/15
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Barry Nelson <star...@gmail.com> writes:

> I can boot D64 and D71 CP/M images but not D81.

Yes, that is to be expected. D71 images may or may not cause problems if
CP/M suddenly decides that it does not want to read tracks beyond 35 on
a device that it considers a 1541.

> This seems related to a short coming in all the SD2IEC variants,
> including the uiec and this one, a lack of support for SRQ/fast serial
> support in the 1581 emulation.

No - the inability to boot CP/M from a D81 disk image has nothing to do
with fast serial support. That comes only into play later, when CP/M
tries to determine the drive type after it has already started to boot.

>>From the thread, it appears that CP/M insists on running a 1581 in fast
> serial mode, and will not boot work if the fast serial support check fails,
> which it does on a SD2IEC device since it is not supported.

Slightly wrong... CP/M on the 1581 uses a 1581-specific
autoboot file ("COPYRIGHT CBM '86") that the drive automatically
executes. The code in this file installs a redirection that will
redirect the first access to track 1, sector 0 (where the C128 boot
sector resides) to a sector on track 40. This probably simplified the
disk layout for 1581 CP/M disks because the system only needs to skip
track 40, without any additional special case for the boot sector on
track 1.

Since sd2iec is not a 1581 emulator, it does not execute such auto-boot
files and the C128 will receive the actual track 1, sector 0 contents
when it tries to boot instead of the redirected one.

> If anyone else has information about this, please share it, I would like to
> get my CP/M D81 images working. I would not mind patching the CP/M system
> files as a solution.

I'm not aware of any CP/M patches for this, so as far as I know
currently your only options are a real 1581 or a drive that is
sufficiently compatible with it.

This behaviour of CP/M is also the reason why there will not be fast
serial support in sd2iec for the current AVR boards, ever. Without
additional hardware there is no way to ensure that every single fast
serial handshake succeeds, but if one fails while a D81 image is active,
there is a chance of data corruption because a write access from CP/M
would use the wrong disk geometry.

By the way, based on your pictures your device is unable to control or
read the SRQ line anyway.

-ik

David Witmer

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Jan 13, 2015, 10:42:02 PM1/13/15
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One thing I found interesting with the products from CMD, the HD could boot from a 1541, 1571, and 1581 partition, but the RamLink could only boot from a 1541 partition.  Also, the @P0 command was needed if the parallel cable was attached to the HD. 
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