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

1.2.4.4 Example 4

clock_st_lua475.gifFigure 10. Example 4

The long clock stretch shown in Example 4 (Figure 10) is uncommon but still easily complies with the SMBus specification (25-ms packet length). Example 4 is a clear example of a clock stretch. As in this example, most clock stretches happen somewhere around the ACK and NACK clocks.