ESP32 UART1 problem

[fodgeri]

HI

We have a restarting problem having pushed the restart button on our developer board.
This board equipped with AMS1117 voltage regulator with the requested capacitors and UART0 has an external pin set for FTDI232 USB board. Also there are two ESP32s on the board connected to GPIO10, GPIO9 crossed the TX/RX (UART1).

The issue is that if I restart one of ESP32 pushing the restart button on it the second one is also restarted.
Doesn't matter which app was flashed into ESPs (the official "SCAN" IDF app was flashed into both ESP) this restart problem is still exist.
This problem is still exist until the UART1 TX cable disconnection on the ESP where the reset was forced. If I'd disconnect the ESP1 UART1 TX the problem is no longer exist.

My assumption is that: there is a electronic transient happening on UART1 TX pin (GPIO10) which could collapse the second ESP too if the connection exist between ESP1 UART TX and ESP2 UART RX.

If you encountered with similar problem and you have already solved it please help to know how.


Thank you

Gary

[ESP_Sprite]

Do you have a schematic of this board we can take a look at?

[WiFive]

Are you sure you can use GPIO10, GPIO9 ?? Usually it is reserved for flash chip.

[fodgeri]

HI

I'm sending a simply schema of our developer board in the attached file.
There is a small mistake at voltage regulator name which is not a 78xx series as you can see in the circuit. We have AMS1171 3.3V voltage regulator in our developer board.

Thank you for your help.

Br,

Gary

[fodgeri]

Are you sure you can use GPIO10, GPIO9 ?? Usually it is reserved for flash chip.

If I'm not mistaken UART0 GPIOs are GPIO1(TX) and GPIO3(RX). And UART0 is the default for flash chip.

[fodgeri]

Sorry

[WiFive]

Are you sure you can use GPIO10, GPIO9 ?? Usually it is reserved for flash chip.

If I'm not mistaken UART0 GPIOs are GPIO1(TX) and GPIO3(RX). And UART0 is the default for flash chip.

Uart0 is the default for the usb-uart but gpio 6-10 are used for spi0 port which is connected to the flash chip on wroom32. You have to reconfigure uart1 to other free pins.

[fodgeri]

Are you sure you can use GPIO10, GPIO9 ?? Usually it is reserved for flash chip.

If I'm not mistaken UART0 GPIOs are GPIO1(TX) and GPIO3(RX). And UART0 is the default for flash chip.

Uart0 is the default for the usb-uart but gpio 6-10 are used for spi0 port which is connected to the flash chip on wroom32. You have to reconfigure uart1 to other free pins.

We have just followed the ESP32 Datasheet doc https://www.espressif.com/sites/default ... eet_en.pdf on page 8 where the UART1 RX/TX were written at the GPIOs (9-10)
Even if sounds logic these GPIOs are connected to SPI (this could cause my ESP is restarting) this is the an official doc what we have followed. .

[WiFive]

gpio9 is the default pin for both u1rxd and spihd. You have to check the schematic for wroom32.

[fodgeri]

We made a new test scenario using the UART2 with GPOI17 (TX) and GPIO016(RX) and there was no restart on the connected ESP32 anymore.
Thank you for your suggestion it seams the problem has been solved.