I just used a pair of buffers, but you might be able to do it with just a resistor. The part number is SN74AUP1G125DCKR. I also put down way too many resistors in case things went wrong. It seems to work well!

After further investigation, I've managed to come up with the following function -- posted here in the hopes that it will help someone else:


#include "esp_private/usb_phy.h"
#include "hal/usb_phy_ll.h"
#include "soc/usb_pins.h"
#include "driver/gpio.h"
#include "esp_check.h"

static esp_err_t ...

After shorting VP to GPIO21 I'm starting to get somewhere. So it definitely seems like it's missing something in the documentation. I'm going to rework a second board and see if I can get something updated.

Is the RCV signal documented anywhere, or will it be?

One slightly concerning thing I'm starting to realize now that I have this board fabricated and I'm finding it doesn't work -- the `RCV` pin appears to be undocumented.

The reference manual on page 756 shows five pins are required: VP, VM, OEN, VPO, and VMO, but I see references in the code to a ...

One thing I've noticed is that `gpio_sig_map.h` has mappings for the following:


#define USB_EXTPHY_VP_IDX 55
#define USB_EXTPHY_OEN_IDX 55
#define USB_EXTPHY_VM_IDX 56
#define USB_EXTPHY_SPEED_IDX 56
#define USB_EXTPHY_RCV_IDX 57
#define USB_EXTPHY_VPO_IDX 57


However those signals are ...

Hi,

I'm designing a board that has USB, and I'd like to still be able to debug it. Accordingly, I've built a small test PCB that breaks out both the int and ext pins to a USB-C connector.

1. At boot, I get SERIAL_JTAG on INT USB
2. If I try the tinyusb console program, I get WARP on INT USB
3. If ...

It looks like the proper component is `driver`, not `drivers`:

Thanks to everyone for their help!

I've done a more thorough analysis, and I've discovered it's a design flaw in the PCB.

Due to space constraints, the ground plane is a bit thin around the level shifter. Unfortunately, the ground return for the UART RX pin is shared with the ground return for the ...

As WiFive noted, the `while (1)` idiom came from the ESP-IDF uart.c driver.

Additionally, I've updated my test program to read 126 bytes at a time. So I know that's not it.

Things have gotten incredibly bizarre, however. I have the UART connected to GPIO22, and I've discovered that wifi breaks ...

In order to simplify the issue and demonstrate it more fully, I've trimmed my code down and created a brand-new project. This project is posted at https://github.com/xobs/esp32-uart-issue

This smaller version simply runs a TFTP server that makes updating easier. I've verified that stopping that ...