This note gives advice on configuring the external circuitry connected to the RPD in order to make it work properly.
This document provides guidance on configuring the external circuitry connected to the RPD (Return from Power Down) pin for ST10 microcontrollers. It details the pin's dual functionality in handling system resets and managing the return from Power Down mode. The text distinguishes between asynchronous and synchronous reset events and explains how the RPD pin level influences these states.
The note covers two specific Power Down modes: Protected Power Down and Interruptible Power Down. It describes the conditions required to enter and exit these modes, including the role of the NMI pin and Fast External Interrupt pins. Furthermore, it provides examples and formulas for sizing external RC networks connected to the RPD pin to ensure correct oscillator stabilization and reset behavior.
| Valid for models | ST10F27x, ST10R27x, ST10F25x and ST10F296 |
|---|---|
| Power-on reset stabilization time | about 1ms to 10ms |
| Internal pull-down current | ~200µA |
| Minimum RSTIN pulse for synchronous reset | > 500ns |
An asynchronous reset must be used during the power-on of the device because the logic does not need a stabilized clock signal to detect it.
An RSTIN pulse must be longer than 10ms to force the device into an asynchronous reset.
An EXxIN pin must be asserted for at least 40ns to exit Power Down mode.