I'm completely out of the loop with GB303, just bumping to ask of anyone still has a copy of this version (or any version that can save on a flashcart) (if i'm even correct in thinking this can...)

thanks

Hi all.
Just received GB-303 from Kitch Bent rev 2.1. Looks like it has the same bugs from 2015.
Also found that GB-303 not work with DMG IPS screen (chaos controls).
LSDJ sync works time to time and async.
Speed of GB-303 not the same as LSDJ (if don't use any sync) I set 188bpm and GB slow down, looks like original bpm on 0,5 bpm less.
To play Song need to clicl SELECT + START +START
Song mode play like it has 16 steps and 1 step delay.

Nice sound but many bugs. But I'm still interested in final working product.

Hello, if you of the community is interessted, i would test it hear with my gear and the cv sync cables. If the people wanna use the gb303 with the korg volca range or monotribe. Git ems card to test. If i can help, let me know

Correct, it is up to the listening device to accept the data as it arrives. Normally triggering an interrupt to process the data or put it in a buffer for later.

If you miss a key off command, you'll know about it.

But midi doesn't do checksums or retransmits, shouldnt the midi device just accept sysex like other midi devices do?

But midi doesn't do checksums or retransmits, shouldnt the midi device just accept sysex like other midi devices do?

Midi serial isn't that fast but with one or two bytes added for checksum and correction you begin to add latency,  added is the fact that the gb is waiting for the bytes and then needs to process the data. This all happens very quickly until a bit is skipped. Worst case it will request the byte again from the external device etc...

A skipped bit needs to be detected and then the port flushed to resynchronise. This is typically done by switching modes from slave to master and sending a byte. More time wasted.

The GB needs to do all this while still executing its code, gui etc... A rom like this should be built around the serial port rather than having it a serviced subroutine.

Is midi serial speed really high speed? I always thought the gb max speed was way above midi spec.

The GB's serial port is really not suited to high speed data without corruption. Error detection is required which adds data overheads,  latency and if you want it 100% robust then there are penalties.

Carefull matching of clock cycles between the GB and external interface is generally required if you want to maintain high speeds.

The code is opensource so it should be easy enough to find.

I'll work on the midi bugs first. Once I get a reliable data transfer we can assess the latency and see if it is an issue

Oh I didn't know that!
you lost your dev env and the sources?

Yes, sure...
I got ideas but maybe you could compile feature requests?

What I would like to see in GB303:
- correct MIDI handling, without skipped notes (I think you already solved some bugs in this area)
- MIDI-triggered drums - because I think that drum sounds are way more impressive than the bass sound
- MIDI-triggered samples

What do you think?

I tried to code the second item myself, but it didn't really work, because of the incoming MIDI bug....

Thx

The project got stalled when I lost most of my data with a hdd crash. I'll set the dev environment back up and crack on with it if someone wants to point me in the right direction to develop this further?

A solid design strategy is more helpful than 'make it like LSDJ' etc...

BennVenn, have you made any progress, or have you lost interest in this project?
thx

Is there an update on this project? I'm glad seeing the GB303 being open sourced because when i first heard of it i thought it was a fantastic idea. shame it failed and got abandoned.

Its funny i was thinking a while ago of building an arduinoboy for the mGB ROM but also add pots and buttons on the arduino itself and convert it from a simple GB to midi converter into a dedicated mGB controller. unfortunately my programming skills are really far from capable. just looking at the arduinoboy source code freaked me the hell out!

Happy Friday everyone!

Now that the save stuff is pretty much done (there will be a bit more to come) progress will be on the MIDI and other bugs in which case all the work I do from here can be applied to the original ROM which will work on your original hardware. There may be fixes which can't be applied to both forks and as there are very few with the original hardare the focus will really be on the new fork of the code.

Do you have the hardware to flash your cart? (Given the WE pin mod)

It is possible yes, but would require some modifications and would lose the use of the pots.