M365BMS

Xiaomi M365 BMS (battery management system)

Hardware

• ST STM8L151K6T6 MCU
• TI BQ7693003 Li battery AFE
• Ricoh R5434D40xA Li battery secondary protector

I/O ports

I/O	Pin	Mode	Function
PA5	5	IN	?
PB0	13	OUT	Red LED
PB1	14	OUT	Blue LED
PB6	19	IO	AFE SDA
PB7	20	IO	AFE SCL
PC2	27	?	UART 115200
PC3	28	?	UART 115200
PC5	30	IN	Config strap, goes to reg51.0
PC6	31	IN	Config strap, goes to reg51.1

Registers

Index	Size	Description
00	02	Magic 5A5A
10	0E	Serial number
17	02	Firmware version
18	02	Factory capacity
19	02	Actual capacity (this is not charge level !)
1B	02	Charge full cycles
1C	02	Charge count
20	02	Manufacture date
30	02	Status
31	02	Remaining capacity, mAh
32	02	Remaining capacity, %
33	02	Current, x10mA, positive - discharging, negative - charging
34	02	Voltage, x10mV
35	02	bTemperature1:bTemperature2, Deg C, 0 is -20
36	02	Balancing bitmap
3B	02	Health, %
40	02	Cell 1 voltage, mV
41	02	Cell 2 voltage, mV
42	02	Cell 3 voltage, mV
43	02	Cell 4 voltage, mV
44	02	Cell 5 voltage, mV
45	02	Cell 6 voltage, mV
46	02	Cell 7 voltage, mV
47	02	Cell 8 voltage, mV
48	02	Cell 9 voltage, mV
49	02	Cell 10 voltage, mV
51	02	Config straps, .0 - PC5, .1 - PC6
70	0C	Activation data (MCU UID copy)

30 Status register

Bit	Description
0	config valid
1	reg50!=0 - ?
2	n/a
3	n/a
4	ArgFromCmd52 - ?
5	n/a
6	IsCharging
7	MainState.field_A - ?
8	n/a
9	overvoltage
10	overheat
11	n/a
12	n/a
13	n/a
14	n/a
15	n/a