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BQ79600-Q1: No response from bq79600

Part Number: BQ79600-Q1
Other Parts Discussed in Thread: BQ79616

Tool/software:

Hello I am using custom-made bq7900 board. I would like to read the part ID of the device. below is my sequence

1. Send Wake ping ( : I see that dvdd=1.8V, VDD=5.0V)

2. send these 0x80, 0x00, 0x02, 0x21, 0x20, 0x02, 0xD6, 0x68  ( part id of device )

Can you please confirm the CRC bytes and frame format.?

I am not receiving a response from bq79600

Comments about my circuit:

1. I connected INH directly to BAT

2. using a 3.3V MCU

3. tried with TX,RX 10k pullup to 3.3V, ( tried all 3 scenarios ),RINH - 100k is not place on device, 10R resistors are shorted with small wire. Please check schematics

Please suggest me what should be done to receive data from device

  • Hi MourishPatel,

    You have too many bytes and the INIT byte is not correct... The correct frame is (just for register 0x2120 PART_ID):

    0x80 - Init Byte + DataSize

    0x00 - Device Address

    0x21 - Start Register MSB

    0x20 - Start Register LSB

    0x00 - Number of registers to read (0x00 means 1)

    0x6C - CRC byte MSB

    0x14 - CRC byte LSB

    Regards,

    Viktor.

  • Dear Viktor,

    Thankyou.  bq79600 is responding and i am able to read data.

    Now I have connected bq79600(COMH_p) to bq79616(COML_P) similarly N. After bq79600 wake ping. I am sending following

    81 00 03 09 01 2F 8E

    to wake up stack devices. Is this ok or should I send DIR_SEL=1 before this? attaching my schematic..Please check if the isolation transformer (HMU1228NL) is ok?

    Thanks&Regards

    Mounish

  • Dear Viktor,

    Thankyou.  bq79600 is responding and i am able to read data.

    Now I have connected bq79600(COMH_p) to bq79616(COML_P) similarly N. After bq79600 wake ping. I am sending following

    81 00 03 09 01 2F 8E

    to wake up stack devices. Is this ok or should I send DIR_SEL=1 before this? attaching my schematic..Please check if the isolation transformer (HMU1228NL) is ok?

    update: 

    I have also tried by sending data in the following sequence

    Hardware: Removed, transformed,r and connected a 2.2nf   i.e used capacitive isolation 

    Some observed info: bq79616-->COMP,COMN : 2.5V,2.5V bq79600-->COMP,COMN : 2.195V,2.195V

    1. Wakeup ping on bq7900

    2. DIRE SEL=1: 81 0 3 9 80 EF EE     ( As I am using COMHP,COMHN and left COMLN,COMLP unused)

    3. Send a wakeup  to the stack  81 0 3 9 20 EF 96

    Thanks&Regards

    Mounish