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MC33771 CRC

Question asked by huang ziyi on Jan 27, 2018
Latest reply on Feb 5, 2018 by huang ziyi

Hi, I have a little question about the crc part of the MC33771's  responce ,its a simple question ,but i am a little confused.

hopefully you can  solve my confuseness.

As you can see the picture taken from datasheet page58,section 6.4.  as follow:


I don't know if my understanding is correct, this is my understanding :

         CRC of read response is only relevant of these data——that is, it is calculated by these data ——

and CRC of write response is only relevant of these data ,that is,it is calculated by these data ——

is this understanding right?

and the crc of slave(33771)'s responce  has no relevance with the CRC of command——which send by the master, is this understanding right?

if so, if the master want to check if the write operation was OK( the write command send to slave),the master has to calculate the correct CRC using those data slave supposed to responce(show in the picture above),and then compare with the actual CRC in the slave's response, right?

but if the Master want to check if read opration is OK,because Master don't know the data of slave‘s  register,sure it don't know what data the slave suppose to responce, so it has to calculate CRC using the data which the slave send back in response, then compare it with the actual CRC  in slave's responce. right?