How to use PDR_ON Pin on STM32F407ZET6?

[SKIM.2]

Hi. I have been using MCU STM32F407ZET6.

But I don't know how to connect PDR_ON pin exactly.

Nowadays there are some errors about this chip on board.

I saw your document named AN4488.

But I still don't know how to make a schematic about PDR_ON pin.

Could you explain how to connect PDR_ON pin and how to make a schematic?

[waclawek.jan]

Connect it to VDD if you want to use the internal reset circuitry. If VDD never drops below 1.8V, ie. in most of the cases, you most probably want to use this option, and forget about AN4488 etc.

Only if you want to use the 1.7V-1.8V VDD range (at limited temperature range) you need to connect PDR_ON to external supervisor.

JW

[SKIM.2]

Thanks for your reply. I am rookie about this field. Maybe I will use PDR_ON pin for general purpose. I use 3,3V VDD, and is there any need to connect resistor? If I should connect resistor, what resistor value I need?

Also sorry to bothering you, ​could you explain the reason why I should connect PDR_ON Pin with VDD and could you tell me the document related it?

[waclawek.jan]

You can't use PDR_ON as a general-purpose IO. You don't need to connect a series resistor.

JW