si7021 i2c command sequence

Thread Starter

yef smith

Joined Aug 2, 2020
54
Hello,As shown there are A,Sr,R,NA,NA*

A-is acknowledge as said in AN0011 manual' During the next bit-period, the slave pulls SDA low (ACK)

Sr-SDA goes low while SCL high. It is allowable to generate a STOP before the repeated start. SDA can transition to high before or after SCL goes high in preparation for generating the START.

Regarding the NA and NA* shown bellow ,NA is not acknowledge .one device refuses to the communication of the other.

What is the difference between NA and NA* and what is the logic of putting them there?
Thanks.

https://www.silabs.com/documents/public/application-notes/AN0011.pdf



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Thread Starter

yef smith

Joined Aug 2, 2020
54
NACK- is pulling SDA high.
but if we look in logical way,NACK means slave doesnt agree with the communication with master.
What is the purpose in that?
Thanks.
 

trebla

Joined Jun 29, 2019
209
If conversion is done, slave will pull down SDA and sending ACK. There is two methods for communication, clock stretching by slave holding SCL down or waiting ACK from slave. Not very convient.
 
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