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Original question:

BQ34Z100-G1: When reading data from BQ34Z100 do I need a Stop after each block, or will just a restart work?

BQ76940: With the I2C interface, is there a minimum time between Stop and Start?

Kipton Moravec
Expert 1545 points
Part Number: BQ76940
Other Parts Discussed in Thread: BQ34Z100,

I just finished working on the bq34z100 and have started working on the bq76940. 

I cannot find anything in the specification about the minimum time delay between a I2C Stop and I2C Start.  In the bq34z100 there was a minimum of 66 us  between the Stop and Start. My software ts taking about 10 or 10.5 microseconds between Stop and Start. Is that going to be a problem? 

From what I understand, the bq34z100 has a watchdog timer and needed the 66 us to be able to reliably reset the watchdog timer. 

Is there a similar watchdog timer in the bq76940 that I have to be concerned about? 

If not can I just do a restart instead of a start and stop when reading the blocks of data? It is a little faster. 


  • 0
    TI__Guru* 81034 points
    Hi Kipton,

    There is no similar requirement like the 66 us for the watchdog on the bq76940. 10.5 microseconds between Stop and Start should be okay according to Table 6.6 of the datasheet. It states a minimum Time the bus must be free before a new transmission as 4.7 us.

    Best regards,
    Matt