T-PicoC3 communication between processors

forest

Hi,
Could somebody provide a simple example how Esp32C3 and Rp2040 communcate in this board ? I suspect it is by serial but not sure what pins are used

woeful

Here are some fragments from my code (which does not do anything useful yet, but does communicate with the ESP-32 to send its first command). I hope it is helpful.

Header file lilygo_tpicoc3.h

// Link to the ESPC3-C3 processor on the same board
#define TPICOC3_ESP32C3_UART 1
#define TPICOC3_ESP32C3_TX_PIN 8
#define TPICOC3_ESP32C3_RX_PIN 9
#define TPICOC3_ESP32C3_CTS_PIN 10
#define TPICOC3_ESP32C3_RTS_PIN 11

Set up RP2040 UART to communicate

uart = uart_get_instance(TPICOC3_ESP32C3_UART);

// The ESP32-C3 hardware can run its UARTs at up to 5 Mbaud
uart_init(uart, 115200); // Default for ESP-AT's hardware reset (?)
gpio_set_function(TPICOC3_ESP32C3_TX_PIN, GPIO_FUNC_UART);
gpio_set_function(TPICOC3_ESP32C3_RX_PIN, GPIO_FUNC_UART);
gpio_set_function(TPICOC3_ESP32C3_CTS_PIN, GPIO_FUNC_UART);
gpio_set_function(TPICOC3_ESP32C3_RTS_PIN, GPIO_FUNC_UART);

uart_set_hw_flow(uart, true, true); // Use CTS and RTS
uart_set_format(uart,8,1,UART_PARITY_NONE);

From the communication code. Must wait a short time (120 ms for the screen to wake up is enough for the ESP-32 as well).

// Send command: starts with AT and must end with \r\n
uart_puts(uart, "AT\r\n");  // Most commands are AT+...\r\n

Multi-line reply, ends with a full line OK\r\n or ERROR\r\n