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Question, i.MX28 power block

Question asked by AVNET JAPAN FAE (team share account) on Feb 25, 2016
Latest reply on Mar 3, 2016 by Artur Petukhov

Hi All,


My customer is developing their i.MX28 custom board.

As for the power supply, they want to use VDD5V for normal operation.

And when the VDD5V is lost, i.MX28 has to continue to work with DCDC_BAT input for system shutdown operation. After the shutdown operation, i.MX28 should be powered-off.

For the above operation, the customer is considering how they should construct the power block including register setting.

Their understanding is as below.

Are those correct?



When PSWITCH is pulled-up, i.MX28 will go into re-boot after VDD5V is lost whether HW_POWER_RESET_PWD_OFF bit is 0.

In this case, to power-off i.MX28, one has to clear PWD_OFF bit and then set PWD bit.



When PSWITCH is pulled-down, i.MX28 will go into power-off right after VDD5V is lost if HW_POWER_RESET_PWD_OFF is cleared.

In this case, one has to clear PWD_OFF bit after the necessary processing when VDD5V is lost to make i.MX28 power-off.


Please show me how they should construct the power block and the register settings.