Formatting MAC address ble_gap_addr_t.addr

[Eliot Stock]

I'm using this code to log the BLE MAC address on my peripheral device, an nRF51822.

void ble_log_mac_address(void)
{
	// Log our BLE address (6 bytes).
	ble_gap_addr_t addr;
	uint32_t err_code = sd_ble_gap_address_get(&addr);
	APP_ERROR_CHECK(err_code);

	NRF_LOG_RAW_INFO("\n%s\n", (int)addr.addr);
}

The output looks like this:

≴?A?b`

How do I get this into a more familiar format, such as this (and what is this format called, btw)?

D8:02:5C:D0:AC:77

Can I do this purely with a format string for NRF_LOG_RAW_INFO()?

[Sigurd]

Hi,

I would have done it like this:

void ble_log_mac_address(void)
{
    // Log our BLE address (6 bytes).
    ble_gap_addr_t addr;
    // Use sd_ble_gap_addr_get() for NRF_SD_BLE_API_VERSION=3
    uint32_t err_code = sd_ble_gap_address_get(&addr);
    APP_ERROR_CHECK(err_code);

    NRF_LOG_RAW_INFO("\n%02X:%02X:%02X:%02X:%02X:%02X\n",
                     addr.addr[0], addr.addr[1],
                     addr.addr[2], addr.addr[3],
                     addr.addr[4], addr.addr[5]);
}

[Eliot Stock]

Thanks. Isn't there a limit to the number of varargs you can pass the NRF_LOG macros? I'm not getting any output.

[Sigurd]

Have you enabled the NRF_LOG ? See here. You need NRF_LOG_ENABLED and NRF_LOG_BACKEND_SERIAL_USES_UART for logging over UART.

[Eliot Stock]

Yes and I'm getting plenty of other log output from this source file and elsewhere.

[Sigurd]

Try to add "NRF_LOG_FLUSH();" after "ble_log_mac_address();". Note that ble_stack_init() must be called before ble_log_mac_address()is called.

[Eliot Stock]

Like I said, there's a limit to the number of varargs you can pass these macros and you don't get any error of you go over it. This works:

// Because the NRF_LOG macros only support up to five varargs after the format string, we need to break this into two calls.
NRF_LOG_RAW_INFO("\n%02X:%02X:%02X:", addr.addr[0], addr.addr[1], addr.addr[2]);
NRF_LOG_RAW_INFO("%02X:%02X:%02X\n", addr.addr[3], addr.addr[4], addr.addr[5]);