Thanks for your help everybody

Tried playing C-2 to C8 but still no sound.

- I started again on the breadboard, is there anything obvious that stands out?
- I used CatSkull's unmodified code: https://github.com/catskull/Arduinoboy currently at 9a3ed0c.
- I'm also powering the teensy with 5v from the gameboy itself so I've cut the USB power from the VCC, i thought this might have been an issue but the teensy is receiving midi. I also can see the device on my mac in the MIDI Studio app and can see messages coming from Live to Midi Monitor.
- I'm building with Teensyduino 1.52 on macOS 10.15.7
- I set the USB Type to "MIDI", "All of the Above" didn't want to connect to my computer as a midi device.
- It's a Teensy 3.2
- I set the Speed to 72MHz, the one just under the overlock setting.
- I wasn't sure that the serial to/from were around the right way to i tried both with no luck.

Currently the pins are:

Teeny 16 - link pin 3-SCK (green)
Teeny 17 - link pin 2-SIN (orange)
Teeny 18 - link pin 4-SOUT (red)
Ground   - link pin 6-GND (red)
n/a      - link pin 1-VCC
n/a      - link pin 5-SD

I might try seeing what the output of the link cable shows in the oscilloscope next but if anybody has any other ideas please let me know!

This doesn't account for my initial problem (and rich's), so I'll have to continue investigating if I want to use trash's most recent builds, but I'm happy to have it making noise in the meantime. If I find out anything more that may be useful to anyone else with similar issues, I'll follow up here.

Thanks again to everybody who offered help and advice - I'll post the finished build in another post when I'm done!

I don't have a link cable, and am intending to build the teensy inside the GBP, so at the moment I have the 4 connections that would usually be through the link cable hard wired between the teensy and the GBP. I've triple checked these, and they seem to line up as expected (double checked with a meter and everything), but I'll unsolder them completely and see what behavior changes. There may be an aspect to hard wiring these connections that I'm overlooking in comparison to using a broken out link cable. Some error on my part here might also account for the difference in behavior between your fork and the standard build, but I don't know enough yet to be sure.

Thanks again for all the input. I'll be updating this thread whether I solve my issues or not in the hopes it can help others who run into similar issues.

3) What happens if you unplug the link cable completely? Disconnect it from the teensy. Seems like I've seen midiout mode get "stuck" if it thinks it's receiving data from the gameboy.

I'd honestly be surprised if my fork does anything differently really. It sounds like it's more of a system/OS issue. My code is 99% the same.

I tried both the version Trash80 posted, as well as catskull's fork, and neither worked off the bat. After trying swapping the usb cable, as well as using several different midi sending programs (I was using Reaper, but also tried several free keyboard programs as suggested), I still wasn't having any luck.

I eventually tried swapping the Arduino USB Type to "All Of The Above," and I've finally gotten the LEDs to respond to the midi out from Reaper. I haven't gotten it to talk properly to the GBP yet, but there's plenty of things I can try and troubleshoot on that before I give up, first being my wiring.

A couple quirks I'm running into though on the Arduino side:

1. Due to the "All of the Above" USB setting, the Teensy enumerates a ton of virtual devices, and clogs up midi selection menus due to this. A small price to pay, but I'll be trying the other USB types to see if any others work as All of the Above does.

2. I still could not get the version that Trash80 linked to to work as of yet. Currently only catskull's fork is responding for me.

3. On all versions I have tried to use, using the mode button does not loop back to 1 after 7. If I click past 7, no lights will light up from mode changes, and I have to use a clear EEPROM sketch to empty the memory. The only way I've found to avoid this is to set the number of modes in the main Arduinoboy.ino sketch to 6, in which case it goes to 6 then wraps back to 1 no problem. Is this indicative of anything specific I'm doing wrong?

4. When trying to use the USB type "MIDI", I often was getting driver crashes whenever I tried to access the Teensy midi device in any program. This doesn't appear to be happening anymore with All of the Above selected, but I thought it was worth noting.

Thanks again for all the help, I'm very new to all of this still. If anybody has any insight to the strange behavior, I'd love to hear it. In the meantime, I'm going to making sure my serial connections to the GBP are correct.

Just download it and try it. This link is to the previous version before the change were made

The usbMode variable is used to output midi over the serial port in the Arduino, you shouldn't use it, but also I don't think it will do anything if you're using USB midi one way or the other.

Yeah the latest code is what I use on mine, I use Teensy LC but I can't see how a 3.2 would behave any differently.

What program are you using to send midi? Have you tried a different one, like the one I linked to above? I just like to rule out any possibility of software issues.

The other idea I had is I've seen a handful of people where their USB cable is bad. It supplies power, but the data lines are broken and won't send any data. If this was the case here, I'd think the teensy wouldn't even show up on the PC at all, but it's an easy and quick thing to just try a different cable!

Really sorry to hear people are having trouble! I want people to DIY these, I don't want to be the only option for a working arduinoboy!

Maybe a last ditch effort would be to use my fork? https://github.com/catskull/Arduinoboy
The only difference should be that I use an internal pullup for the button switch, so you can just remove the resistor for the push button and wire it directly to the arduino and ground.

The usbMode shouldn't be enabled, correct? https://github.com/trash80/Arduinoboy/b … y.ino#L112
I've tried it on and off just in case, but it makes no difference.

I've tried the byte change that you suggested, as well as trying output on channels 1-16, but still haven't had any luck.

Is the 1.3 release of Arduinoboy what I should be using for this? I'm new to both github and Arduino so I'm just making sure I'm not missing something obvious here. As far as I can tell, 1.3 supports Teensy and USB support according the documentation.

Ultimately, if I can't get it working, I'll purchase one of your prebuilt Teensyboys which look awesome - I was just hoping to learn something from getting this running if I can.

Thanks again for the help.

Maybe try a simpler midi program to send the midi data? I use this and really like it: https://flit.github.io/projects/midikeys/

Also I'd try sending midi on all the channels. By default mGB works on channels 1-5 but it's possible the eprom got messed up if you had a previous sketch running that changed it. On this line: https://github.com/trash80/Arduinoboy/b … y.ino#L115
Just change one of those 4 bytes to something else, for example change the first one from 0x7F to 0xFF and then reupload.

The thing that's the most confusing is that the LEDs work on boot, so it must just not be receiving MIDI data in the ways it's wanting to, most likely on the wrong channels.