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MC33771 not response

Question asked by huang ziyi on Feb 4, 2018
Latest reply on Feb 5, 2018 by huang ziyi
Hello :
      for the another problem I have encountered :

I am writing a code to communicate a mc9s12g64 MCU with the MC33771 (SPI communication).

I wrote the functions to build the command frames (including calculating the CRC and appending it to the frame) according to the datasheet, and I'm running a test that does the following:

1) Send a wake-up pulse;

2) Send an INIT command and sending a READ comand in a loop.;

As follow:

 

I use a logic analyzer to verify if the MC33771 is responding to my commands. According to the datasheet, even if I send an incorrect command, the MC33771 sends a response frame.

However, I observed that the MC33771 is not responding ,the signals are as the picture follow:

The first line of the picture above is ENABLE(CSB). The second: CLOCK(sclk)  . Third: MISO. Fourth: MOSI.

I don't if anyone else has also run into this problem .

And I also do not understand why the MC33771 keep sending me 0xB2 at the fifth byte of the command sending to it.

Appreciate it very much If you can pay attention to my question !

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