Images, successes and failures

[GrantMTG]

Hi all, I'm new to a lot of things in this project (STM32, its toolchain, github), but do have experience with 8-bit embedded including USB and MIDI. I own one of those heathen MIDI adapter cables so I ordered some of the PCBs and started my learning curve.

Hardware: pretty much done and tested: MIDI side works with simple test programs I wrote. USB starts enumeration and gets part way, so I think all hardware is OK or nearly so. Usual power supply, clock and IO tests all OK.

Tools: I installed GNU Arm Embedded Toolchain on my Win8 machine as well as STM32CubeIDE and MX. STM tools will build the Debug configuration but on downloading via STM32 ST-LINK Utility, no joy. I don't know how to step, set breakpoints, etc yet. I had more luck with GCC and the Makefile. Originally there was a problem with the build and I had to remove -nostartfiles from the make. After that build was OK and some joy when I programmed midiusb.bin again using STlink utility.

Firmware: The enumeration is stopping when the host requests "GetDescriptor (String iProduct)". It does get the language info and the (default) serial number string. So I guess there is some disconnect here in the firmware or build where String iProduct is choking. This is part of the aftermarket personalization you guys added I think. Anyway, that's where I am at, so any help appreciated. Also, if there is a better way to communicate, let me know.

[GrantMTG]

Well I have a workaround. For now. It looks like appInitialization() in appMain.c is not picking up the "flag" correctly. Perhaps once I "SysexGen" it, it will, but the uninitialized (first time) is failure. I just commented out the

if(flag == 0)

case and it works!

I do have some hardware comments, minor ones. I will run tests, but my gut is telling me that the pull-up on the opto's open collector output is unnecessarily strong. I changed R11 from 330R to 4k7. I will probably also reduce the current in the CONNECT_LED by changing R6 to 1k. I prefer to use efficient (modern) LEDs that draw less current and hence the MCU has less to sink.