Hello, please help me determine the RXD and TXD pins for the SIM800L on the A4S board. The pins mentioned (13 and 15) in this forum thread do not work. I also want to point out that on the A2 board, the pins for GSM were listed as 13 and 34 as mentioned here, but in reality, they turned out to be 13 and 5. I am using my own script on ESP-IDF.
this pins for A2 works well
#define UART_TX_PIN 5
#define UART_RX_PIN 13
this pins for A4s doesn't work
#define UART_TX_PIN 34
#define UART_RX_PIN 13
this pins for A2 works well
#define UART_TX_PIN 5
#define UART_RX_PIN 13
this pins for A4s doesn't work
#define UART_TX_PIN 34
#define UART_RX_PIN 13