Notes on fix for Music Thing Workshop System MIDI on Windows devices

gistfile1.txt

Solutions in these notes entirely generated by ChatGPT - use with caution 


1 Service the USB device every pass through loop()

Symptom fixed: hard-fault a few seconds after Windows starts flooding the control endpoint.
Windows sends class–specific SET_INTERFACE / SET_CUR requests in quick bursts; if the device 
code is busy in analogRead() etc. and never re-enters TinyUSB for > ~3 ms the control EP0 
state machine underflows and panics.

void loop() {
 // --- PATCH 1: keep TinyUSB alive on Windows -------------
 TinyUSBDevice.task();          // << NEW – poll USB engine

2 Trim over-long string descriptors (< 31 chars)
Windows’ built-in USB-Audio/MIDI driver rejects interface strings ≥ 32 UTF-16 code-units and tears 
the whole device down .
Your current strings are 32 chars long.

void setup() {
   // Initialise MIDI
-  TinyUSBDevice.setManufacturerDescriptor("Music Thing Modular");
-  TinyUSBDevice.setProductDescriptor("Workshop System MIDI");
+  TinyUSBDevice.setManufacturerDescriptor("MT Modular");
+  TinyUSBDevice.setProductDescriptor("Workshop MIDI");

3 Give Windows a unique iSerialNumber

Without one, each time you plug into a new USB port Windows adds a fresh registry entry, 
quickly exhausting the 10-device MIDI quota and corrupting earlier entries 
 – after which new connections crash during enumeration.

Add just after the other descriptors:
#include "pico/unique_id.h"   // <-- NEW

void setup() {
  ...
+  // --- PATCH 3: per-board serial number -------------------
+  char serial[2 * PICO_UNIQUE_BOARD_ID_SIZE_BYTES + 1];
+  pico_get_unique_board_id_string(serial, sizeof serial);
+  TinyUSBDevice.setSerialDescriptor(serial);

NB: I'm not certain this is working


4 Enlarge TinyUSB’s MIDI FIFOs (Windows bursts > 64 bytes)
Windows DAWs often dump several hundred bytes of parameter state immediately after opening a port.
With the default 64-byte RX buffer TinyUSB overruns, asserts, and the RP2040 reboots 

#define CFG_TUD_MIDI_RX_BUFSIZE  512
#define CFG_TUD_MIDI_TX_BUFSIZE  512
#define CFG_TUD_MIDI_EP_BUFSIZE   64

5 Throttle your own CC spam just enough
Even with bigger FIFOs you’re sending up to 8 CCs every ~2 ms when a DAW is also sending data.
Give TinyUSB a chance to flush:

if (analog[i]->hasChanged()) {
    MIDI.sendControlChange(45 + i, analog[i]->getValue() >> 5, 1);
-   delay(1);                // old
+   tud_task();              // << replace delay with USB poll
}
delay(1) blocks interrupts; tud_task() services USB and returns in ~30 µs.