NuMicro® NUC029LEE/NUC029SEE32-bit Arm® Cortex® -M0 MicrocontrollerAug, 2018 Page 297 of 497 Rev 1.00NUMICRO® NUC029LEE/NUC029SEE TECHNICAL REFERENCE MANUAL6.10.4 Basic ConfigurationThe WDT peripheral clock is enabled in APBCLK[0] and clock source can be selected inCLKSEL1[1:0].Or user can setting CONFIG0[31] is 0 to force Watchdog Timer enabled and active in 10 kHz afterchip powered on or reset.6.10.5 Functional DescriptionThe Watchdog Timer (WDT) includes an 18-bit free running up counter with programmable time-out intervals. Table 5-29 shows the WDT time-out interval period selection and Figure 6.10-3Watchdog Timer Time-out Interval and Reset Period Timing shows the WDT time-out interval andreset period timing. WDT Time-out InterruptSetting WTE bit to 1 will enable the WDT function and the WDT counter to start counting up.There are eight time-out interval period can be selected by setting WTIS. When the WDT upcounter reaches the WTIS settings, WDT time-out interrupt will occur then WTIF flag will be set to1 immediately. WDT Reset Delay Period and Reset SystemThere is a specified TRSTD delay period follows the WTIF flag is setting to 1. User should set WTRbit to reset the 18-bit WDT up counter value to avoid generate WDT time-out reset signal beforethe TRSTD delay period expires. If the WDT up counter value has not been cleared after the specificTRSTD delay period expires, the WDT control will set WTRF flag to 1 if WTRE bit is enabled, thenchip enters to reset state immediately. Refer to Figure 6.10-3 Watchdog Timer Time-out Intervaland Reset Period Timing, the TRST reset period will keep last 63 WDT clocks then chip restartexecuting program from reset vector (0x0000_0000). The WTRF flag will keep 1 after WDT time-out reset the chip, user can check WTRF flag by software to recognize the system has been resetby WDT time-out reset or not. WDT Wake-upIf WDT clock source is selected to 10 kHz, system can be waken-up from Power-down modewhile WDT time-out interrupt signal is generated and WTWKE bit enabled. In the meanwhile, theWTWKF flag will set to 1 automatically, user can check WTWKF flag by software to recognize thesystem has been waken-up by WDT time-out interrupt or not.WTIS Time-Out Interval PeriodTTISReset Delay PeriodTRSTD000 24 * TWDT (3/18/130/1026) * TWDT001 26 * TWDT (3/18/130/1026) * TWDT010 28 * TWDT (3/18/130/1026) * TWDT011 210 * TWDT (3/18/130/1026) * TWDT100 212 * TWDT (3/18/130/1026) * TWDT101 214 * TWDT (3/18/130/1026) * TWDT110 216 * TWDT (3/18/130/1026) * TWDT
