[sdiy] Crumar bit one EPROM .bin anyone

Ullrich Peter Peter.Ullrich at kapsch.net
Tue Jan 24 09:31:36 CET 2017


Yes, also the Crumar Bit One uses 8051/8031 microcontrollers!
8051 for keyboard decoding, 8031 for the synth control.

Schematics are here:



Von: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] Im Auftrag von Tony K
Gesendet: Dienstag, 24. Jänner 2017 04:55
An: <synth-diy at synth-diy.org>
Betreff: Re: [sdiy] Crumar bit one EPROM .bin anyone

This reminds me of the Jupiter-6 version 2 that powered up in Omni mode. The trick was to connect a Midi cable from Out to In on power up to make it respond on Ch.1 .
You could always try that.

If course a firmware upgrade is best.
Sorry can't help you with that, short of disassembling and modifying the code yourself if you have that ability or motivation. On the JP-6 it's pretty straight forward. Do you know if the Bit One used an 8051? Most synths of that era used either a Z80 or 8051.


On Jan 23, 2017, at 3:23 PM, "Luc Van Den Bosch" <luc.ky at telenet.be<mailto:luc.ky at telenet.be>> wrote:
Hi all, I have a Crumar bit one and that synth has the annoying “feature” to be in midi omni mode when you switch it on.
It should be possible to disable omni with parameter 64 and 65 but that doesn’t work on my bit one which apparently means I have an older version of the firmware (parameter 64 and 65 don’t show any value and it should be 1 or 0).
Does anyone have the binaries for the 2 EPROM to share?
I found downloads here: http://dbwbp.com/index.php/9-misc/37-synth-eprom-dumps but the version seems to be the same because also  with this version parameter 64 and 65 are not shown.


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