• State
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 972 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ34Z100 I2C Multi byte write (incremental writes)

Morgan Smith35
Prodigy 70 points
Other Parts Discussed in Thread: BQ34Z100

Hello, in the datasheet it says you can only write one byte at a time, if you attempt an incremental write all extra bytes will be be NACK.

This doesn't seem to be the case.

When I use the BQEV software I can send 2 byte words to an address and there is no NACK.

I am trying to unseal a pack and I can only unseal it using the BQEV software when I send 16bit words, these apparently can't be sent according to the data sheet.

The scope shows, AA, 00 , 14, 04, this is clearly a multi byte message. Am I misunderstanding the datasheet?

If I send them one byte at a time to address 0 then address 1, the unseal doesn't work.

Perhaps you can shead some light on this.

Thanks

Morgan

  • 0
    TI__Guru 73830 points

    Morgan,

    The device can read and write more than one byte. The datasheet mentions that the address pointer auto-increments to allow multiple bytes to be transferred.

    The “quick read” returns data at the address indicated by the address pointer. The address pointer, a register
    internal to the I2C communication engine, increments whenever data is acknowledged by the bq34z100 or the
    I2C master. “Quick writes” function in the same manner and are a convenient means of sending multiple bytes to
    consecutive command locations (such as two-byte commands that require two bytes of data).

    Tom

  • 0 in reply to ThomasCosby
    Intellectual 630 points

    How many bytes of data can we read and write in an incremental read or write I2C communication?

    An EEPROM I use allows 255 byte of data to be written in a sequential write after which a stop and new start condition is required to write in the next page of EEPROM.

    Is there any such limitation with bq34Z100?

  • 0 in reply to selva nathan
    TI__Guru 73830 points
    Data has to be read and written to the data flash in 32 byte blocks.
  • 0 in reply to ThomasCosby
    Intellectual 630 points

    That means max 32 bytes can be written or read in a single incremental read or write

    Thank you Sir