Operating System
Others
Arduino IDE version
Arduino 2.3.4
Board
Waveshare RP2040 zero
ArduinoCore version
Rasberry Pico 5.0.0
TinyUSB Library version
3.7.2
Sketch as ATTACHED TXT
#define CFG_TUSB_DEBUG 2
#include "Adafruit_TinyUSB.h"
uint8_t const desc_hid_report[] = {
TUD_HID_REPORT_DESC_KEYBOARD()
};
Adafruit_USBD_HID usb_hid(desc_hid_report, sizeof(desc_hid_report),
HID_ITF_PROTOCOL_KEYBOARD, 2, false);
void setup() {
TinyUSBDevice.setID(0x04D9, 0x0024);
TinyUSBDevice.addInterface(usb_hid);
TinyUSBDevice.begin();
usb_hid.begin();
unsigned long start = millis();
while (!TinyUSBDevice.mounted() && millis() - start < 8000) {
yield();
}
Serial1.begin(115200);
Serial1.println(TinyUSBDevice.mounted() ? "MOUNTED" : "TIMEOUT");
}
void loop() {
}
Compiled Log as ATTACHED TXT
log github.txt
What happened ?
When using Adafruit_USBD_HID configured as a Boot Protocol Keyboard on RP2040, the device enters an infinite Bus Reset loop when connected to certain USB hosts. The device rarely completes enumeration and TinyUSBDevice.mounted() almost never returns true.
The issue occurs with the Sound Devices PixE5 but not with the Sound Devices PIX240, which is another recorder from the same manufacturer. The device also works fine when connected to a standard PC.
How to reproduce ?
1 - Configure Adafruit_USBD_HID as a keyboard with Boot Protocol:
Adafruit_USBD_HID usb_hid(desc_hid_report, sizeof(desc_hid_report), HID_ITF_PROTOCOL_KEYBOARD, 10, false);
2 - Connect RP2040 to a Sound Devices PixE5 via USB
3 - Observe Serial logs
Expected behavior
Device enumerates successfully, tud_mount_cb() is called, TinyUSBDevice.mounted() returns true.
Actual behavior
Infinite Bus Reset loop, enumeration almost never completes. Occasionally (~1 out of 10 attempts) the device does enumerate successfully, suggesting a timing or race condition rather than a hard incompatibility:
USBD init on controller 0, speed = Full
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
...
No GET_DESCRIPTOR request is ever processed.
What I have already tried
Reducing CFG_TUD_ENDPOINT0_SIZE from 64 to 8 → no effect
Simplifying the HID report descriptor to a minimal boot keyboard → no effect
The device works perfectly when connected to a Windows/macOS PC
The device works perfectly when connected to a Sound Devices PIX240 (same manufacturer, older model)
Reproducibility
This bug is difficult to reproduce without access to a Sound Devices PixE5. This is a professional piece of equipment used in film and television production. I am happy to run any diagnostic code or provide additional logs if needed !
The fact that enumeration occasionally succeeds suggests a timing or race condition during the enumeration phase, possibly related to how the RP2040 handles the first GET_DESCRIPTOR request after a Bus Reset.
A USB analyzer log is available if needed.
Debug Log as ATTACHED TXT
No response
Screenshots
Here are the TinyUSBLog (#define CFG_TUSB_DEBUG 2) : 
I have checked existing issues, pr, discussion and documentation
Operating System
Others
Arduino IDE version
Arduino 2.3.4
Board
Waveshare RP2040 zero
ArduinoCore version
Rasberry Pico 5.0.0
TinyUSB Library version
3.7.2
Sketch as ATTACHED TXT
#define CFG_TUSB_DEBUG 2
#include "Adafruit_TinyUSB.h"
uint8_t const desc_hid_report[] = {
TUD_HID_REPORT_DESC_KEYBOARD()
};
Adafruit_USBD_HID usb_hid(desc_hid_report, sizeof(desc_hid_report),
HID_ITF_PROTOCOL_KEYBOARD, 2, false);
void setup() {
TinyUSBDevice.setID(0x04D9, 0x0024);
TinyUSBDevice.addInterface(usb_hid);
TinyUSBDevice.begin();
usb_hid.begin();
unsigned long start = millis();
while (!TinyUSBDevice.mounted() && millis() - start < 8000) {
yield();
}
Serial1.begin(115200);
Serial1.println(TinyUSBDevice.mounted() ? "MOUNTED" : "TIMEOUT");
}
void loop() {
}
Compiled Log as ATTACHED TXT
log github.txt
What happened ?
When using Adafruit_USBD_HID configured as a Boot Protocol Keyboard on RP2040, the device enters an infinite Bus Reset loop when connected to certain USB hosts. The device rarely completes enumeration and TinyUSBDevice.mounted() almost never returns true.
The issue occurs with the Sound Devices PixE5 but not with the Sound Devices PIX240, which is another recorder from the same manufacturer. The device also works fine when connected to a standard PC.
How to reproduce ?
1 - Configure Adafruit_USBD_HID as a keyboard with Boot Protocol:
Adafruit_USBD_HID usb_hid(desc_hid_report, sizeof(desc_hid_report), HID_ITF_PROTOCOL_KEYBOARD, 10, false);
2 - Connect RP2040 to a Sound Devices PixE5 via USB
3 - Observe Serial logs
Expected behavior
Device enumerates successfully, tud_mount_cb() is called, TinyUSBDevice.mounted() returns true.
Actual behavior
Infinite Bus Reset loop, enumeration almost never completes. Occasionally (~1 out of 10 attempts) the device does enumerate successfully, suggesting a timing or race condition rather than a hard incompatibility:
USBD init on controller 0, speed = Full
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
USBD Bus Reset : Full Speed
...
No GET_DESCRIPTOR request is ever processed.
What I have already tried
Reducing CFG_TUD_ENDPOINT0_SIZE from 64 to 8 → no effect
Simplifying the HID report descriptor to a minimal boot keyboard → no effect
The device works perfectly when connected to a Windows/macOS PC
The device works perfectly when connected to a Sound Devices PIX240 (same manufacturer, older model)
Reproducibility
This bug is difficult to reproduce without access to a Sound Devices PixE5. This is a professional piece of equipment used in film and television production. I am happy to run any diagnostic code or provide additional logs if needed !
The fact that enumeration occasionally succeeds suggests a timing or race condition during the enumeration phase, possibly related to how the RP2040 handles the first GET_DESCRIPTOR request after a Bus Reset.
A USB analyzer log is available if needed.
Debug Log as ATTACHED TXT
No response
Screenshots
Here are the TinyUSBLog (#define CFG_TUSB_DEBUG 2) :
I have checked existing issues, pr, discussion and documentation