Read Serial without USB

[alve89]

Hey guys,

since this post viewtopic.php?t=7886#p36604 brings the sad message, that the ESP32 cannot be supplied with an external power supply, I thought of using USB to power the ESP32 Dev Kit v1 board and use some pins for read the Serial interface. Is that possible? And, if yes, what do I need to do to read out Serial with some RX/TX pins?

Many thanks in advance and best regards
Stefan

[ESP_Angus]

Hi Stefan,

The ESP32 SoC can be powered from an external power supply.

There are some ESP32 development boards where the ESP32 can't come out of reset if the onboard USB to serial chip isn't powered. On these boards providing 5V to the "5V" pin on the board doesn't allow it to work. As far as I know this is not the case for any Espressif development boards, but it's a problem with some third party development boards.

Whether this is a problem for your particular development board depends on the details of that board, unfortunatley some names like "DEV KIT V1" have been used a lot so you really need to check with whoever made it.

If you plan to power your board via the USB port (with a charger or similar) as per your post, then you won't have the problem described in the linked post - even if the board can't be powered via the 5V pin. It should "just work".

To read/write serial you can connect any 3.3V TTL serial interface. It's possible to either use the default UART0 TX & RX GPIO pins, or you can configure one of the other UARTs to use any GPIO pins of your choice.

Angus

[alve89]

Hi Angus,

thank you for your reply. It seems that I have a third party board (which is working properly except of the 5V input pin).

About your suggested TTL serial interface - would this work to read serial via pins -> USB: https://www.az-delivery.de/products/ftd ... 6542809426

And can I also write to the ESP board with this converter?