BQ27220：how to use the subcommand , i try send the subcommand(0x0001) to get the value(example 0x0220) but can not get ,

yancheng shen

Intellectual 265 points

Part Number: BQ27220
Other Parts Discussed in Thread: BQ27320, BQSTUDIO,

i test other subcommand ,get the value alway is 0x0000 ,what is the problem ? there have somebody to help me thanks!

over 7 years ago

0 Onyx Ahiakwo over 7 years ago

TI__Guru* 76230 points

Hi Yancheng
pls review this document below. It will give you additional insight on how to communicate with the gauge.

www.ti.com/.../slua801

thanks
Onyx

0 yancheng shen over 7 years ago in reply to Onyx Ahiakwo

Intellectual 265 points

first to thanks to your response :

this link i have get but i also can not get the infomation example (send subcommad (0X0001) to get the value 0x0220) , the stand command is ok !only the subcommand is can not get the infomation,so what is the problem ,can you help me?

0 Onyx Ahiakwo over 7 years ago in reply to yancheng shen

TI__Guru* 76230 points

hi Yancheng

See example below reading device no . Though it was done on a different gauge, it is a similar process for this gauge.

Another example reading the firmware version

thanks

onyx

0 yancheng shen over 7 years ago in reply to Onyx Ahiakwo

Intellectual 265 points

get the value (0x00 0x00)

0 Beginner over 7 years ago in reply to yancheng shen

TI__Intellectual 2461 points

Hi,

Please refer to this appication note http://www.ti.com/lit/an/slua467b/slua467b.pdf and attached image clipped by I2C sniffer.

The communication of bq27520 is the same with bq27320. I think the key point is the SR(Repeat START) of read package. Not just read from this command.

0 yancheng shen over 7 years ago in reply to Beginner

Intellectual 265 points

like this i can not get 0xa5ff (BQ_HW_VERSION) ,there have some problem? please help me!

0 yancheng shen over 7 years ago in reply to Beginner

Intellectual 265 points

if i want to get BQ_DEVICE_NUMBER or BQ_FW_VERSION ,i can get 0xa5ff ,why BQ_HW_VERSION can not ?

0 yancheng shen over 7 years ago in reply to Beginner

Intellectual 265 points

0 Dominik Hartl11 over 7 years ago in reply to yancheng shen

TI__Guru 64816 points

Please check TRM, 2.1.2: Sub command 0x0001 (DEVICE_NUMBER) instructs the gauge to return the device type to MACData().

MACData() starts at 0x40.

So the sequence is: Issue sub command 0x0001 (write 0x01 0x00 to I2C address 0x00 and 0x01) and then read 2 bytes from I2C address 0x40 (MACData()):

0 yancheng shen over 7 years ago in reply to Dominik Hartl11

Intellectual 265 points

i have done according to you give me the information ,but can not get device_number_id(0x0220);

0 Onyx Ahiakwo over 7 years ago in reply to yancheng shen

TI__Guru* 76230 points

Have you tried this with bqstudio? Can you do so and sniff the buss to see the commands being send and implement your code to be similar.
thanks
Onyx

0 yancheng shen over 7 years ago in reply to Dominik Hartl11

Intellectual 265 points

the "mod" is what ?

0 Onyx Ahiakwo over 7 years ago in reply to yancheng shen

TI__Guru* 76230 points

Hi Yancheng,
A quick google search would have told you what "mod" is. Mod returns the remainder after a division of one number by another.
en.wikipedia.org/.../Modulo_operation

eg: mod(5,4)=1
mod(5,5)=0

thanks
Onyx

0 yancheng shen over 7 years ago in reply to Onyx Ahiakwo

Intellectual 265 points

like this to init is ok？but i can not to modify design capital;

0 Dominik Hartl11 over 7 years ago in reply to yancheng shen

TI__Guru 64816 points

It's a bit different for the bq27220 See

BQ27220: BQ27220 checksum calculation

TI E2E Community

Part Number: BQ27220 Bq27220 checksum calculation: I am trying to set design capacity for BQ27220 from the default 3000mAH to 13200 mAH using the external MCU to write I2C command to update the RAM area of BQ27220 . But when I follow the 16 steps described...

If you want to set design capacity to 4043mAh (=0x0FCB), you have to execute the following sequence:

1. Enter CFG_UPDATE mode
2. Write the address AND the parameter data to 0x3E+ (auto increment)
3. Calculate the check sum: 0xFF - (sum of address and data) OR 0xFF
4. Write the check sum to 0x60 and the total length of (address + parameter data + check sum + length) to 0x61
5. Exit CFG_UPDATE mode

w aa 00 90 00 #CFG_UPDATE
w aa 3e 9f 92 0f cb # design capacity = 0x0FCB
w aa 60 f4 06 # 0x9F + 0x92 + 0x0F + 0xCB = 0x020B. 0x020B OR 0xFF = 0x0B. CS = 0xFF - 0x0B = 0xF4; 2 bytes address, 2 bytes data, 1 byte check sum, 1 byte length = 6
w aa 00 92 00 #EXIT_CFG_UPDATE

0 yancheng shen over 7 years ago in reply to Dominik Hartl11

Intellectual 265 points

thanks for your response!

i also can not modify the design capisacty according to you tell me information

0 Onyx Ahiakwo over 7 years ago in reply to yancheng shen

TI__Guru* 76230 points

Can you test out using bqstudio first and verify that works before trying to implement on your system.
thanks
Onyx

Power management

Power management forum

BQ27220：how to use the subcommand , i try send the subcommand(0x0001) to get the value(example 0x0220) but can not get ,

BQ27220: BQ27220 checksum calculation