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BQ20Z95: I2C(SMbus) bit sequences, Multi byte return reception, MCU communicate

yj w
Prodigy 130 points

Part Number: BQ20Z95

hi,

MCU communicate with IC qb20z95, The sbs command, ManufacturerName(0x20), has 12 bytes returning, but I could only receive 2 bytes, what can I do?

My bit sequence: Start + 0x16 + ACK + 0x20 + ACK + Sr + 0x17 + ACK + return length byte + ACK + return byte1+ACK+return… + Stop.
The bit sequence meets the requirements of smbus110.pdf Page26.(Block Read)
But I could only receive 2 bytes. why?

another question:

Bq20z95 Sealed to Unsealed，default unsealkey is 0414，3672.

My bit sequences:Start+0x16+ACK+0x00+ACK+0x14+ACK+0x04+ACK+Stop+Start+0x16+ACK+0x00+ACK+0x72+ACK+0x36+ACK+Stop. （Execute within 4 seconds）

Is it right?This is your engineer's guidance, I don't know if I understand it right. or as smbus110.pdf Page25.(Block Write)?

Thanks

  • 0
    TI__Mastermind 25955 points
    Hi Yj,

    Here are the commands without PEC, where:

    S: Start
    A: Ack
    N: Nack
    P: Stop

    For ManufacturerName(0x20):

    S + 0x16 + A + 0x20 + A + S + 0x17 + A + 0x0B + A + 0x54 + A + 0x65 + A + 0x78 + A + 0x61 + 0x73 + A + 0x20 + N

    For UNSEAL with default key:

    S + 0x16 + A + 0x00 + A + 0x14 + A + 0x04 + N
    S + 0x16 + A + 0x00 + A + 0x72 + A + 0x36 + N

    Sincerely,
    Bryan Kahler
  • 0 in reply to Bryan Kahler
    Prodigy 130 points
    hi Bryan,
    Thank you very much for your reply.
    The bit sequences was confirmed by you.
    then I check the reading carefully, trying to slow down the frequency. Now the problem has been solved.
    Thanks again