This application note introduces the use of Watch Dog Timer (WDT) function for products using SyncMOS MCU, including WDT enable bit, WDT reset bit, WDT count overflow period selection, etc., and select the appropriate WDT reset period according to the needs.
The document provides an overview of the Watch Dog Timer (WDT) function used to prevent system lock‑up in SyncM05 microcontrollers. It lists the applicable products and describes how the WDT can be enabled, cleared and configured.
Usage instructions include register definitions (WDTC, WDTKEY, SCONF), selectable reset‑time options for each MCU model, and example code in both assembly and C language. The note covers eight reset‑time options and shows how to protect the control registers during operation. This manual is written in Chinese.
| WDT reset‑time options (SM59264, SM59128, SM894051, SM79108, SM79164) | 2.048 ms to 262.144 ms (8 steps) |
|---|---|
| WDT reset‑time options (SM8954A, SM8958A, SM89516A) | 16.38 ms to 2097.15 ms (8 steps) |
| Number of WDT reset‑time selections | Eight |
The WDT function offers eight selectable reset‑time options.
Set WDTC to 10000110b to start the WDT timer, then protect the register with the appropriate WDTKEY sequence.
The WDTKEY register (WDTKEY) must be written with the sequence 0xE1 then 0x1E before modifying WDTC.