Using LTC6811 as an I2C master

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Joined Apr 23, 2022
I'm trying to understand using LTC6811 as an I2C master.
If I understood correctly the commands to the LTC are sent by pulling the CSB pin low and sending the clock and data to SCK and SDI pins?
For LTC to send a command to the I2C bus you need to write data to it's COMM register, so you use WRCOMM command. I don't understand exactly how you send the command. You send the 2 command bytes corresponding to the WRCOMM command, followed by the 2 PEC bytes. Do you then send next 6 bytes of data to be written to the COMM register? What if you want to write only 1 byte, is that possible?

I'm also having trouble understanding the read/write control words from table 19.
Let's say I want to write 1 byte of data to a slave device on the bus. How would the COMM register look?
ICOM0 would be START
Data0 would be a 7 bit address followed by a low R/W to indicate a write
What should FCOM0 be?
From what I understand I2C, in this situation it's the slave that would be generating an ACK/NACK bit, not the master as written in table 19.
After that, to send the data byte, ICOM1 would be BLANK to proceed directly to the transmission.
FCOM1 I once again don't understand what should be.
ICOM2 should be STOP to end the communication. What happens to the last byte of data in the COMM register? It is not transmitted?

I also don't fully understand the No transmit action. Would I use this in a situation where there are multiple masters on the bus, to allow another master to transmit? Also would I use this after sending a read command to a slave, to allow the slave to transmit the data back? Is there any other use for this action?

Also let's say there's a situation I need to send 4 bytes to the I2C bus. The communication starts off the same, I write 6 bytes to the COMM register, 1 address and 2 data, start the communication, but what happens after that? I still have 2 bytes of data I couldn't write to COMM, how do I know that the data has been sent and I can write to COMM again?


Joined Mar 14, 2023
What kind of device are you going to use to communicate with this chip? Does your device have a I2C module? I had worked on some I2C chips a few years back and found the most help from reading a general reference on I2C protocol standards which all I2C devices must roughly follow.