SN8P2604
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 41
Version 1.1
3.2 POWER ON RESET
The power on reset depend no LVD operation for most power-up situations. The power supplying to system is a rising
curve and needs some time to achieve the normal voltage. Power on reset sequence is as following.
Power-up:
System detects the power voltage up and waits for power stable.
External reset (only external reset pin enable):
System checks external reset pin status. If external
reset pin is not high level, the system keeps reset status and waits external reset pin released.
System initialization:
All system registers is set as initial conditions and system is ready.
Oscillator warm up:
Oscillator operation is successfully and supply to system clock.
Program executing:
Power on sequence is finished and program executes from ORG 0.
3.3 WATCHDOG
RESET
Watchdog reset is a system protection. In normal condition, system works well and clears watchdog timer by program.
Under error condition, system is in unknown situation and watchdog can’t be clear by program before watchdog timer
overflow. Watchdog timer overflow occurs and the system is reset. After watchdog reset, the system restarts and
returns normal mode. Watchdog reset sequence is as following.
Watchdog timer status:
System checks watchdog timer overflow status. If watchdog timer overflow
occurs, the system is reset.
System initialization:
All system registers is set as initial conditions and system is ready.
Oscillator warm up:
Oscillator operation is successfully and supply to system clock.
Program executing:
Power on sequence is finished and program executes from ORG 0.
Note: Please refer to the “WATCHDOG TIMER” about watchdog timer detail information.