Hello,
evolution board MPC5777C-DEVB_QSG (SCH-29962)
Do you mean NXP evaluation board?
We made an external power supply 1.25 V, 3.3 V and 5 V with a sequence that the 1.25 V (VDD) rises by 200 ms after a voltage of 3.3 V and 5 V
The micro will be held in reset until the core voltage rise to 1.2V. No execution is performed.
By measuring, we found that the evolution board has power up of 1.25 V almost at the same with a voltage 3.3 V and 5 V.
Yes, as this is most common case when you want to start your application as soon as possible after power is applied.
Is there any limit (min., nom., max.) for the delay of the supply 1,25V power up after 3.3V and 5V? In our experience, 200 ms is too much.
No, there is no limit defined for that. Usually you want to have micro fully operational in less then 100ms.
power up sequence with all tests could take 20-40ms + startup code another 50ms. So you apply the core voltage in same time as VDD_HV or if its generated from HV, then there a slight delay.
Best regards,
Peter
