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DAC60501: I2C Address byte: 9bit or 8bit?

Darren (FAE)
Expert 5483 points
Part Number: DAC60501

According to the Datasheet of the DAC60501 P18 (attached image), Table 1 shows the Address (A) byte as having 9bits (DB[32:24]), while Figure 9. shows the SCL and SDA timing requirements for the Address byte is 8bit, followed by the Aknowledge bit. All the other bytes (Command, MSDB, LSDB) are 8bit.

Table 1 should show Address (A) byte as having 8bits (DB[31:24]), correct?

 

  • 0
    TI__Genius 14220 points

    Hi Darren,

    Welcome to E2E and thank you for your query. The I2C frame has an 8-bit data (from sender) + 1-bit ACK (from the receiver). That technically makes the frame size 9 bits. But it's actually 8 bits of data.

    If you are using a standard I2C peripheral, you need to send only 8 bits. The ACK bit will be taken care of by the protocol.

    Hope that answers your question.

    Regards,

    Uttam Sahu

    Applications Engineer, Precision DACs

  • 0 in reply to Uttam Sahu
    TI__Expert 5483 points

    Hi Uttam,

    I understand the frame size is technically 9bits, but the data is 8bits.

    But in this case, I believe DB[32:24] in the datasheet is incorrect? The frame size may be 9bits, but Table 1 includes the ACK, and all the others (command byte, MSDB, LSDB) still show 8bits (ex: DB[7:0])

    Anyway, you have answered my question, so I will click "Resolved".

    For future reference, the datasheet should probably be revised though...