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Trusted Platform Module (A71CH) I2C Clarifications

Question asked by Nathan Barrett Morrison on Jun 1, 2018

Hello,

 

We're trying to use an A71CH with a (non NXP) processor that's running a Linux distribution.

 

I'm bringing the A71CH up by putting the chip in reset and driving the lines as follows:

  • SCL = 1
  • SDA = 1
  • IF0 = 1
  • IF1 = 0
  • RST_N = 0

I then wait 1000 microseconds and set RST_N = 1 and wait another 1000 microseconds and then proceed to start the I2C bus later on.

 

When doing an i2cdetect on the bus from Linux, I do not see any addresses being found for the TPM.  I do see some other devices that are connected on the bus.

 

Is there any reason i2cdetect would not find the A71CH part?

 

In the A71CH data sheet, there is a reference to an application note of an195015 which I cannot find.  This application note is supposed to contain information on NXP's "Smartcard I2C protocol."  Where can I find this application note?

 

Thanks,

Nathan

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