TCA7408: Read from Register

Hey Hiro,

This datasheet does not seem to specify the repeated start condition (the datasheet is a little old).

This was taken from TCA6408A but the idea is still the same.

"However, they inserting start condition before that because they think this is an procedure based on the I2C standard."

Technically this is never talked about in the I2C standard as the I2C standard does not discuss repeated start conditions. If the customer wants to go by the book then they can also do a stop condition then a start condition instead of a repeated start assuming this is a one master bus. (repeated starts are used when there are multiple masters who may take control of the bus when they see a stop condition)

"Please give us your advice whether there Is any bad influence for the device behavior  with their usage."

The way the customer is doing this is okay and though not very common, the industry does use repeated start conditions like what the customer is doing (it is typically more common in multi-master buses ).

Thanks,

-Bobby