OAK-D-IoT-40 | UART connection on the ESP32-WROOM-32D

neil

Hi everyone 🙂
My main goal is to get the metadata directly from the ESP32-WROOM-32D module via UART protocol instead of Bluetooth or Wi-Fi.

When I checked the OAK-D-IoT-40 schematics and ESP32-WROOM-32D-MODULE datasheet; I can see that pins 38, 35 and 34 are GND, TXD0 and RXD0 respectively.

My questions are:
1 - Is it possible for me to establish a physical connection with the ESP32 using the UART protocol by soldering pins to the relative peripheral input (marked in the image below) ?

2 - Is there a simpler way to achieve this and am I over complicating the process 😅

Cheers!

David

Hi Neil,

The UART interface you are referring to is used for the flashing of the ESP32 module, so you should rather not use same interface as you will loos the ability to debug the code at the same time as stream metadata from it.
AFAIK you can connect to any unused GPIO as ESP32 can mux the UART to any of the pins that are available.
But please check first that you won't potentially use any PU/PD on the boot strap pins if you will be connecting to those for some reason.
Enabling UART should be trivial if you do that on ESP only not connecting it to OAK-SoM-IoT.
@erik might also be able to give any additional thoughts on that or correct me if I am wrong on something.

Regards,
David

neil

Thank you so much for the detailed answer @David,

This is very helpful. My main goal is to use the device in standalone mode and get the meta-data from ESP via TX with a ser.write() method. I can see that in this esp32-spi-message-demo "uart_echo" example I can configure GPIO pin 34 as TX and technically transmit my metadata via that pin?

However based on your advice I shouldn't use that pin since it is used to debug the code, therefore I can choose another unused GPIO pin and set that as GPIO output GPIO(GPIO.OUTPUT, GPIO.ALT_MODE_5) is that correct?

Finally given that my goal is to get the metadata from the device via UART using only TX/GND (to force a one way communication) would you say that another module in Luxonis shop might provide a more straightforward peripheral access for this task?

Thanks heaps!
Neil

David

neil I would suppose so, but I am really not an expert when it comes to ESP32 programming.
@erik would be able to better confirm the implementation when he gets a chance.

WRT other modules, we don't really have many only OAK-D-IoT-40 and OAK-D-IoT-75 does come with ESP32 and there is not much of difference between them. Depends on your use case and how you use SPI connection between OAK-SoM and ESP32 you may be able to connect to one of the AUX connectors which might be easier.

Please note that we do not normally offer a support on IoT modules anymore as we sort of deprecated those modules due to low interest, but we will continue with the production for the requested demand.

Regards,
David

erik

(WRT firmware on ESP32; I am not familiar with ESP IDF and can provide much info on it. Best to check their documentation page though)

neil

Thanks very much team! That sorts out my weekend plans 😃 If I can't figure it out I probably will pivot to a different hardware design.

dpunzeng

Hi neil,

did you get anywhere with your plans? I am on the same track to get counting data via tx basic protocol out of a minimalistic HW…