warnemuende-lighthouses/firmware/components/remote_control/uart_service.c

#include "include/uart_service.h"
#include "esp_log.h"
#include "include/remote_control.h"
#include "sdkconfig.h"

static const char *TAG = "uart_service";

// Service UUID: 6E400001-B5A3-F393-E0A9-E50E24DCCA9E
const ble_uuid128_t gatt_svr_svc_uart_uuid =
    BLE_UUID128_INIT(0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x01, 0x00, 0x40, 0x6E);

// RX Characteristic UUID: 6E400002-B5A3-F393-E0A9-E50E24DCCA9E
const ble_uuid128_t gatt_svr_chr_uart_rx_uuid =
    BLE_UUID128_INIT(0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x02, 0x00, 0x40, 0x6E);

// TX Characteristic UUID: 6E400003-B5A3-F393-E0A9-E50E24DCCA9E
const ble_uuid128_t gatt_svr_chr_uart_tx_uuid =
    BLE_UUID128_INIT(0x9E, 0xCA, 0xDC, 0x24, 0x0E, 0xE5, 0xA9, 0xE0, 0x93, 0xF3, 0xA3, 0xB5, 0x03, 0x00, 0x40, 0x6E);

uint16_t tx_chr_val_handle;

// Callback function for GATT events (read/write on characteristics)
int gatt_svr_chr_uart_access(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt *ctxt, void *arg)
{
    switch (ctxt->op)
    {
    case BLE_GATT_ACCESS_OP_WRITE_CHR:
        // Check if the RX characteristic is being written to
        // if (ble_uuid_cmp((const ble_uuid_t *)&ctxt->chr->uuid, (const ble_uuid_t *)&gatt_svr_chr_uart_rx_uuid) == 0)
        {
            // Get data from the buffer
            uint16_t data_len = OS_MBUF_PKTLEN(ctxt->om);
            char *data = (char *)malloc(data_len + 1);
            if (data)
            {
                int rc = ble_hs_mbuf_to_flat(ctxt->om, data, data_len, NULL);
                if (rc == 0)
                {
                    data[data_len] = '\0';
                    ESP_LOGI(TAG, "Received data: %s", data);
                }
                free(data);
            }
            return 0;
        }
        break;
    default:
        break;
    }
    return BLE_ATT_ERR_UNLIKELY;
}

// Function to send data via the TX characteristic
void send_ble_data(const char *data)
{
    ESP_LOGI(TAG, "Preparing to send data: %s", data);

    struct os_mbuf *om;

    for (int i = 0; i < CONFIG_BT_NIMBLE_MAX_CONNECTIONS; i++)
    {
        if (g_connections[i].is_connected)
        {
            om = ble_hs_mbuf_from_flat(data, strlen(data));
            if (om)
            {
                int rc = ble_gatts_notify_custom(g_connections[i].conn_handle, tx_chr_val_handle, om);
                if (rc == 0)
                {
                    ESP_LOGI(TAG, "Sent data to conn_handle %d: %s", g_connections[i].conn_handle, data);
                }
                else if (rc != BLE_HS_ENOTCONN) // Ignore "not connected" errors if a device just disconnected
                {
                    ESP_LOGE(TAG, "Error sending data to conn_handle %d: %d", g_connections[i].conn_handle, rc);
                }
            }
        }
    }
}

void uart_tx_task(void *param)
{
    char buffer[50];
    int count = 0;
    while (1)
    {
        vTaskDelay(pdMS_TO_TICKS(2000));
        if (is_any_device_connected())
        {
            ESP_LOGI(TAG, "Sending data over BLE UART TX");
            sprintf(buffer, "Hello World #%d", count++);
            send_ble_data(buffer);
        }
    }
}