SLUA475 November   2016 BQ2060A , BQ20Z80 , BQ40Z50-R1 , BQ40Z50-R2 , BQ40Z60 , BQ78350-R1 , BQ78350-R1A

 

  1.   SMBus Made Simple
    1.     Trademarks
    2. 1 Getting to Know SMBus
      1. 1.1 Closer Inspection
      2. 1.2 Final Considerations
        1. 1.2.1 Clock Stretching
        2. 1.2.2 Broadcasting (Master Mode Messages)
        3. 1.2.3 PEC
          1. 1.2.3.1 How to Calculate PEC
        4. 1.2.4 Examples
          1. 1.2.4.1 Example 1
          2. 1.2.4.2 Example 2
          3. 1.2.4.3 Example 3
          4. 1.2.4.4 Example 4
    3. 2 Most Common Problems
    4. 3 Glossary
    5. 4 References
  2.   A SMBus Reference Sheet
    1.     19

3 Glossary

ACK: A bit in the SMBus communication packet used to signify an acknowledgment of the previous byte of data.

Broadcast: A term to indicate when the TI fuel gauge becomes a master on the bus and broadcasts information to the host as a master. This is also sometimes called master mode messaging.

FG: Acronym for fuel gauge

LSB: Acronym for least-significant byte; two bytes of data.

Master: The device on the SMBus that controls the current communication packet. The master controls the clock line on the bus for any given packet.

MSB: Acronym for most-significant byte; two bytes of data.

NACK: A bit in the SMBus communication packet used to signify a no-acknowledgment of the previous byte of data. This abbreviation usually signifies an SMBus error, or it comes at the end of the last byte of a read communication packet.

Packet: A complete SMBus transaction, either read or write, from the start bit to stop bit.

Repeated start: A second start bit in the communication packet used in a SMBus read to transition from writing the SMBus command code to reading data from that command code.

Slave: This is the opposite of the master. The slave does not control the clock line except for clock stretching used to slow the transaction down to allow the slave more time, if needed.

Word: For this document, an SMBus word signifies two bytes of data (0xFFFF), translated from 0–65535 unsigned or –32768 to 32767 signed