How to respond NACK to Master

PYF.1 · ‎2023-02-28

Hello everyone,

I have a application on STM32L5xx, I configuration I2C1 to slave mode,

when slave receive first unwanted command code, I want to response NACK to master. I judge the command code in AL_SMBUS_SlaveRxCpltCallback call back function, and set NACK bit at CR2 register but unfortunately cannot success.

Bubbles · ‎2023-03-02

Hi @PYF.1 ,

to get the ACK control, you need to configure slave byte control mode. The settings are SBC=1, RELOAD=1, NBYTES=1. NOSTRETCH=0. The slave byte control is a whole chapter in the reference manual.

BR,

J

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PYF.1 · ‎2023-03-02

Hi JUUDO,

Thanks for your answer, here I ignore the RELOAD=1, now I could control the ACK at eacch byte

determine response ACK/NACK to master

BR

PYF