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Q: BQ27500 programming problems by 1438059
Hi, I have built a battery testing board based on the circuit on page 34 of BQ27500 data sheet. But I got the follow data:
Input voltage: = [0.17,1.45,2.55,2.89,2.90,3.3,3.97,4.15,5.41] voltage;
Data got by voltage() command: = [03 05;10 100;14 203; 16 69;16 72;17 174;20 137;21 05;23 133];
Should I do some calibration for the BQ27500?
I also tried to use other command to get the state of battery, but the obtained is 0 of 0xFF.
Could you please give me some suggestions on how to identify wheath the BQ27500 is working? Thanks
Best regards,
Q: Re: BQ27500 programming problems by 1438059
Could some one answer my question please? Thanks
Q: Re: BQ27500 programming problems by 317599
Hi David,
What are you using to communicate with the bq27500?Have you use the bq27500 evaluation software on your PC to successfully communicate with a bq27500 evaluation module?
If so, then have you tried to connect the EV2300 to your board and communicate with the bq27500 in your circuit?
Have you had any successful communication with the bq27500 at all on your board?
Regards,
David
We developed a software by ourselves to get the data from bq27500. I didn't buy bq27500 evaluation module, so I have not done any testing by bq27500 evaluation software.
My board is designed based schematic on page 34 of BQ27500 datasheet.
How could I verify a successful communication with the bq27500 on my board. I just charge the Bat pin voltage to check if voltage has some change. The results are listed in the first page.
It sounds like you're not sure if the I2C communication is good at all. Are you trying the examples in this app note?
http://focus.ti.com/lit/an/slua467a/slua467a.pdf
You can try to read the firmware version since you know what the expected value should be. You can also try the Temperature() command.
If possible, I would recommend that you buy a bq27500 EVM which includes an EV2300 USB-I2C interface module. Then you can try two tests to find the problem:
You could also just buy an EV2300 and try #1 only.
A: Re: BQ27500 programming problems by 1438059
bq27500 Evaluation board can read the data from my customised board. But I still get the same value.
Input voltage: = [0.17,1.45,2.55,2.89,2.90,3.3,3.97,4.15,5.41] voltage; Data got by voltage() command: = [03 05;10 100;14 203; 16 69;16 72;17 174;20 137;21 05;23 133]; The current value is 97.b
The current value is 97.b
What is wrong? Could you please give me some suggestions? Should I need to do some calibration? If yes, how could I calibrate it? Thanks
Could anyone answer my questions? How to change the BQ27500 address?
Do you mean change the bq27500's I2C address? This is not possible as it is fixed at AA when running firmware.
I cannot understand your data from the post above. If you can get an EV2300 (or bq27500 EVM which includes an EV2300) then you can use the bq27500 evaluation software to debug this issue. I do not believe it is possible to do your fuel gauging development without these tools. You will need to use the bqEASY wizard in the evaluation software to determine the chemistry ID of your battery and program the chemistry files into your IC.
Nonetheless, let's break down the Voltage() command to explain what you should be seeing.
I have an EVM right now that is reporting a voltage of 4121mV through the evaluation software.
I go to the I2C Pro screen and do the following:
read one byte from command 0x08. Result = 0x19
read one byte from command 0x09. Result= 0x10
Now I flip the byte order to get: 0x1019
Convert to decimal: 4121 (mV)
Can you reproduce this with your setup?
EVM board can read the data from my customised board. But I still get the same value.
Data got by voltage() command: = [0.773;2.660;3.787; 4.192;4.168;4.526;5.257;5.381;6.021];
Current is also not correct.
I also used EVM including TI BQ75200 board. to do a test, the voltatge is very accurate, but the current is not correct. The actual discharge current rate is 1A, but the measured current is 0.283
Could some please answer my questions? Thanks a lot
Did you do the calibration on the Calibrate section of bqEVSW?
Your board may also have a lot of offset since it should only be off by a few millivolts before calibration. If you have a poor layout it might cause such an offset.