ESP32 Forum

Hello forum!

I have difficulties with connecting ESP32-3248S035 board with GPS MatekSys ublox SAM-M8Q.
The ESP32-3248S035 is a rather rare board and the documentation is not so good.

I know it is UART, so I need to connect RX with TX and TX with RX, and GND with GND. But I don't know what voltage in P1 socket labeled "Vn" is on this board (so do I need a voltage converter?). And what are the pin numbers of all these UART pins on the P1 socket of the board? (what pins should I use in the code?)

Can You help me?

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Here are images of the board and GPS module, as well as some docs:










Docs:

http://www.mateksys.com/?portfolio=sam-m8q

https://www.u-blox.com/en/product/sam-m ... -resources

A glance at the schematic (http://pan.jczn1688.com/pd/1/ESP32%20mo ... b854e2561f) seems to indicate

• Pin 1 of P1 is connected to the 5V rail of the board.
• Pins 2&3 are connected to U0TXD and U0RXD of the ESP, as is the CH340C USB<->serial converter

Signal levels on P1 are thus 3.3V.

So, you should be able to communicate over P1 via UART0 of the ESP (GPIO1+3), which is the same UART that's used for uploading firmware. You'll want do disconnect the GPS whenever you flash the chip; and you won't be able to use debug logging via UART0/USB while the GPS is connected.

I've seen these boards in shops, and was tempted to get one; but it seemed as though they were quite limited in IO. Looking at the schematics now, I see that they really are pretty useless IO-wise.