Any issue with ESP-C3 BLE uart and Apple iOS devices ?

[pataga]

I've been using a third party app on my Samsung Android phone to connect to my ESP32-C3 via BLE uart interface, and have no problem receiving data packets sent at 100mS intervals.

But a friend reports that he has not been able to connect with his iOS devices (phone, tablet). The BLE server is not visible.

I don't have any iOS devices to test with.
Is there anything special about iOS devices that needs to be taken care of ? This is the ble-uart initialization code

Code: Select all

#include <esp_gap_ble_api.h>
#include <esp_gattc_api.h>
#include <esp_gatt_defs.h>
#include <esp_bt_main.h>
#include <esp_gatt_common_api.h>
#include "config.h"
#include "ble_uart.h"


#define SERVICE_UUID           "6E400001-B5A3-F393-E0A9-E50E24DCCA9E" // UART service UUID

#define CHARACTERISTIC_UUID_RX "6E400002-B5A3-F393-E0A9-E50E24DCCA9E"
#define CHARACTERISTIC_UUID_TX "6E400003-B5A3-F393-E0A9-E50E24DCCA9E"

NimBLEServer* pBLEServer                = NULL;
NimBLEService* pService                 = NULL;
NimBLECharacteristic* pTxCharacteristic = NULL;
NimBLECharacteristic* pRxCharacteristic = NULL;

static uint8_t ble_uart_nmea_checksum(const char *szNMEA);

void ble_uart_init() {
	NimBLEDevice::init("BLE-Vario");
	NimBLEDevice::setMTU(46);
	NimBLEDevice::setPower(ESP_PWR_LVL_N27);
	NimBLEDevice::setSecurityAuth(true, true, true);
	NimBLEDevice::setSecurityPasskey(123456);
	NimBLEDevice::setSecurityIOCap(BLE_HS_IO_DISPLAY_ONLY);

	pBLEServer = NimBLEDevice::createServer();

	pService          = pBLEServer->createService(SERVICE_UUID);
	pTxCharacteristic = pService->createCharacteristic(CHARACTERISTIC_UUID_TX, NIMBLE_PROPERTY::NOTIFY);

	pRxCharacteristic = pService->createCharacteristic(
		CHARACTERISTIC_UUID_RX,
		NIMBLE_PROPERTY::WRITE | NIMBLE_PROPERTY::WRITE_ENC | NIMBLE_PROPERTY::WRITE_AUTHEN);

	pService->start();
	pBLEServer->getAdvertising()->start();
	}

[pataga]

Never mind, increasing tx power to 0dB fixed the problem with the specific app (XCDisplay). Another app "Bluefruit LE connect" was able to connect even with the lower tx power.