This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSP430FR6043: I2C protocol USS Design Center

Part Number: MSP430FR6043

I am trying to understand the format for encapsulation of the I2C packets communicated between the USS Design Center and the EVM430FR6043 gas flow application.  The packet format itself is clearly documented but I have not found an explanation of the packet encapsulation.  When the USS master is reading data from the EVM the packet is preceded by the slave address byte (transmitted by the master with the read bit set) and then a byte containing the number of bytes in the packet.  When the USS master is writing data to the EVM430FR6043 the structure is less clear to me.  For example when the USS design centre requests a capture I logged the following byte sequence before the start of the packet:

0x14 (this is the slave address 0x0A with the write bit set to 0)

0x55 (undocumented)

0xAA (undocumented)

0x09 (number of bytes in packet)

0x04 (Design Center ID)

0x98 (Command)

...    (rest of packet followed by checksum)

Are the two bytes I have labeled as "undocumented" in fact documented somewhere or can you tell me what they mean?

**Attention** This is a public forum