topic 33907 wake up problem in MPC5xxx

33907 wake up problem

liujinhang — Thu, 25 Aug 2016 08:07:45 GMT

hi,

I have a question about 33907 wake up machanism. see below:

precondition is IO_0 has been configured to be "rising edge wake up 33907".

if MCU program will make 33907 go to sleep by sending an "go to sleep" SPI command. but at this time IO_0 has been high state.

if the IO_0 high state maintains, can 33907 be wake up? if 33907 can not be wake up, how can we do to confirm every time of going into sleep mode can be wake up by an rising edge of IO_0.

from up figure, we can see MCU program cannot make sure send "go to sleep" command of SPI before IO_0 rising edge.

Re: 33907 wake up problem

TomasVaverka — Thu, 25 Aug 2016 12:41:02 GMT

Hi Liu,

We know of this weakness which is by the way corrected on FS6500 family. The workaround is proposed in the AN5766, chapter 6.2 - extracted below:

Best regards,

Tomas

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