ESP-Prog Serial monitor not working on macOS 11 Big Sur

Hi all, here we go with another post on ftdi drivers on Mac OS.
i’ve setup my board → DevKit Board to be working with the ESP-Prog only to have a debugger over the JTAG port and to use the second serial port to display the terminal monitor.

After a lot of work I was able to make the debugger / upload work over the JTAG.
I’ve connected the TX and RX pin to the serial and sometimes I receive something (nulls or nothing or gibberish )

The correctness of the wiring is confirmed by the fact the monitor is perfectly working on a Windows machine.

  • changing USB port makes no difference.
  • the board is powered by the esp prog ( powering by the usb makes no difference)
  • followed all the guide on the FTDI drivers / rebooting / removed kext used the D2xxHelper_v2.0.0 and the FTDIDextinstaller.

Final thought , I think the ftdi port is working correctly (ESP32-prog tx and rx blinks correctly) , but some how the data decoding looks incorrect.
Anyone got an idea where I can look at next?


Did you connect RX->TX and TX->RX in regards to UART?
What baud rate does the firwmare use?
Does PlatformIO’s built-in serial monitor not work in the same way?
Is Redirecting... set accordingly?

Hi thanks for the reply,

  • I did connect RX > RX and TX > TX because of this. (and I confirm it that is working because on windows I receive readable data and leds blinks).

  • boud rate are set the same 115200 (ini and source code) lowering to 9600 makes no difference

  • setting the monitor to the one on board, works but this is forcing me to use 2 cables ( one to the esp-prog for the debug) and one to the Dev kit for the monitor. also im planning to create a new board with only the JTAG and serial connection.

This is my ini


But doesn’t that show then that the on-board UART where the data is coming out is not properly connected to the esp-prog UART?

I mean I can output the serial if I connect a second cable to the board (non the esp-prog).

definetly is connected correctly, because I can read the serial through the ESP-prog on windows, the issue is only on Mac OS.

Okay, but if that is the case, then the issue is Mac specific. Are there any other serial devices available maybe (ls /dev/*serial*)? Or other FTDI drivers are needed?

Things to check:

  • Is /dev/cu.usbserial-14501 the correct device? If I’m not mistaken, two serial devices are created by ESP-Prog.
  • Uninstall any FTDI software. No additional software beyond what’s already part of macOS is needed.
  • Have you connected the RX and TX lines to UART2? UART0 is probably connected to the USB-to-Serial chip. So there would be conflict because two sides are driving the same signal.

yes is the correct device I usually got 2 ports that ends with 00 or 01 .
I’ve removed all the ftdi software and now I got 4 ports
but they looks a copy (if I select n5 is behaving the same way flashing the green led).

I’ve connected the UART0 I don’t see the reason to connect to another one as is working on windows.

I think I have to reinstall a fresh version of my Mac OS.

If you connect it to UART0, two chips drive the ESP32’s RX0 pin. Small differences in the supply voltage could make the difference who wins.

I propose you isolate the problem by testing the ESP-Prog separately:

  • Disconnect the ESP32 development board from the ESP-Prog
  • Connect the ESP-Prog to your computer
  • Connect the RX0 and TX0 pins on the ESP-Prog with a wire (loopback wire)
  • Run screen /dev/cu.usbserial-14101 9600
  • Type some characters. They should appear on the screen.
  • Type CTRL-A, k to exit

If the characters appear, the driver and the ESP-Prog are working correctly and the problem is in the wiring to the ESP32 board. Otherwise, it’s a problem either with the drivers or the ESP-Prog.

If I remember correctly, you should not connect the loopback wire before connecting the ESP-Prog to your computer. The FTDI chip will go crazy.

The four devices (/dev/cu.usb...) don’t look right. Most likely, you still have two drivers creating devices for the same thing.

with the loop back works… stupid me I haven’t thought about it.

ill try next to desolder TX RX and re solder it.
if is not working I will connect to the TX2 RX2

ok I got finally working.
dunno what was, but those are the steps:

  • I’ve reflow the TX RX with a different solder.
  • Using the /dev/cu.usbserial-6 as a monitor.

Still got the serial doubled, I must still have the FTDI driver installed. but thanks all for the support.