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MPC5777C : Clock configuration failure when selecting PLL

Question asked by Daniel Fernandes on Jan 13, 2020
Latest reply on Jan 15, 2020 by Lukas Zadrapa

Hello, 

 

 

I want to configure MPC5777C to use an external oscillator at 40 Mhz (connected to EXTAL pin) with PLL0 and PLL1 as described in the following diagram : 

 

 

The problem I get is that after the register SIU.SYSDIV is written (see below), the microcontroller resets (in loop)

All PLLs apparently lock correctly, it is when selecting PLL1 as system clock that the problem occurs.

 

Do you have any idea what is happening? how can I investigate further and find out the cause of the reset? (SIU.RSR indicates Power On reset)

 

Thanks for the support

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