RPD is a dedicated timing pin for the return-from-power-down circuit. Additionally, when this pin is recognized low, a reset event is taken as asynchronous. This application note gives advice on configuring the external circuitry connected to the RPD pin in order to make it work properly. The information contained in this document is valid for ST10F27x and ST10R27x.
This document details the dual-purpose functionality of the Return-from-Power-Down (RPD) pin on ST10F27x and ST10R27x microcontrollers. It describes how the RPD pin distinguishes between asynchronous and synchronous reset events based on signal timing and level, ensuring proper system startup behavior.
An RSTIN pulse must be longer than 10 ms to force the device into an asynchronous reset.
The internal pull-down device discharges the external capacitor at a typical rate of 100 to 200 pA.
An EXxIN pin must be asserted for at least 40 ns to exit Power Down mode with an external interrupt.