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PROBLEM OF Using UART0 as two functions.
Arij feki , 08-29-2024, 12:30 PM
Hello ,I hope this message finds you well.I have question Is it correct to use the same UART for both flashing (using an FTDI) and communication with a GSM module by using a switch on the GSM TX and RX pins, as shown in the schematic?Thank you in advance for your time and support.Best regards,
Artarka , 08-29-2024, 01:20 PM
You are absolutely need to flash with TXD0 RXD0. I personally leave that open to programmer and use UART1 for comms instead. UART1 can be any pin as there is GPIOMUX within esp32. Again check datasheet and ESP-IDF documentations. You can use UART0, by holding SIM_800L on reset or use a mosfet to switch off the module while programming.
Arij feki , 08-29-2024, 01:58 PM
I have already set up the switcher on the GSM module, but when I test the communication between the ESP32 and the GSM module using the AT command, it doesn't work.
Arij feki , 08-29-2024, 01:59 PM
Artarka , 08-29-2024, 02:08 PM
https://soldered.com/productdata/2018/12/Soldered_SIM800-HW_datasheet.pdf?srsltid=AfmBOoqMNYvURSOSzBNghUto5qHSNWGH0S1fe9xmPfTgJdmJ71U84_XHfew things,have you check that you are actually sending stuffs on Uart0 with oscilloscope?have you turned on the GSM module with pulling down the PWR_KEY for 1.2seconds?have you checked if STATUS pin is high after switching it on?
Artarka , 08-29-2024, 02:09 PM
Arij feki , 08-29-2024, 07:02 PM
I found with the multimeter that the VDD_EXT is 0V.😔
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