topic Re: I2C Interrupt after 8th Bit in Kinetis Microcontrollers

I2C Interrupt after 8th Bit

Joern — Wed, 08 May 2024 12:25:47 GMT

i have to set an address for a I2C slave (MCP 4728) connected to my MK22FN1M0...

Therefore i have change the state of another pin between bit 8 and bit 9.

My idea was to use the TCF interrupt with FACK enabled, because datasheet says:

"48.4.6.1 Byte transfer interrupt
The Transfer Complete Flag (TCF) bit is set at the falling edge of the ninth clock to
indicate the completion of a byte and acknowledgement transfer. When FACK is enabled,
TCF is then set at the falling edge of eighth clock to indicate the completion of byte."

I get the Interrupt at the 9th bit, but i cannot move the interrupt to the 8th bit.

Am i missing something?

Is FACK not changing TCF behaviour if not in SMBus receiver mode?

The behaviour i need is this:

LDAC Pin is on a separate I2C independent GPIO

Re: I2C Interrupt after 8th Bit

_Leo_ — Thu, 23 May 2024 21:41:08 GMT

Hi,

Thank you so much for your interest in our products and for using our community.

You are correct! FACK does not change TCF behavior if not in SMBus mode.

Have a nice day!

Re: I2C Interrupt after 8th Bit

Joern — Mon, 27 May 2024 05:26:57 GMT

Hi Leo,

thanks for the reply!

I will check if i can switch to SMBus mode for that period.

Have a nice one!

Re: I2C Interrupt after 8th Bit

_Leo_ — Mon, 27 May 2024 21:32:23 GMT

You're welcome, any other questions feel free to continue using our technical support service.