5 years, 9 months ago.

I get different serial numbers and firmware revisions on same microbit

I want to get the serial number of BBC Microbits and have come across three methods.

Method 1. Uses the following MicroPython code, via https://python.microbit.org/v/1.1

	from microbit import *

	def get_serial_number():
	    NRF_FICR_BASE = 0x10000000
	    DEVICEID_INDEX = 25 # deviceid[1]
	    @micropython.asm_thumb
	    def reg_read(r0):
		ldr(r0, [r0, 0])
	    return reg_read(NRF_FICR_BASE + (DEVICEID_INDEX*4))

	while True:
	    if button_a.was_pressed():
		display.scroll(get_serial_number())

	    sleep(100)

Method 2. Uses C++, via https://ide.mbed.com/compiler/#nav:/;

	#include "MicroBit.h"
	MicroBit uBit;
	int main()
	{	    
	    uBit.init(); // Initialise the micro:bit runtime.
	    uint32_t sn = microbit_serial_number();
	    char buffer[16];
	    int len = sprintf(buffer,"%d",sn);
	    uBit.display.scroll(buffer);
	    release_fiber();
	}

Method 3. Uses the Android App: Micro:bit Blue, from https://play.google.com/store/apps/details?id=com.bluetooth.mwoolley.microbitbledemo

After pairing via Bluetooth, check the (I)nformation about your microbit and it shows the serial number and firmware version

I get the same result from the first two methods and a completely different result from the 3rd.

For example 212354362 (from methods 1 and 2) and 177223240 (from method 3)

It is the same story on all the microbits I have tested, and I cannot see any relationship between the numbers. In addition, although I have downloaded and installed the latest firmware (0250) from https://microbit.org/guide/firmware/, The Micro:bit Blue App reports firmware version 2.1.1-g

Can anyone explain these differences, and say which is the real serial number and firmware version?