SN8P2604
8-Bit Micro-Controller
SONiX TECHNOLOGY CO., LTD
Page 42
Version 1.1
3.4 EXTERNAL
RESET
External reset function is controlled by “Reset_Pin” code option. Set the code option as “Reset” option to enable
external reset function. External reset pin is Schmitt Trigger structure and low level active. The system is running when
reset pin is high level voltage input. The reset pin receives the low voltage and the system is reset. The external reset
operation actives in power on and normal running mode. During system power-up, the external reset pin must be high
level input, or the system keeps in reset status. External reset sequence is as following.
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.
3.4.1 EXTERNAL RESET CIRCUIT
The external reset circuit is a simple RC circuit as the following diagram.
MCU
VDD
VSS
VCC
GND
RST
R
20K
ohm
C
0.1uF
MCU
VDD
VSS
VCC
GND
RST
R
20K
ohm
C
0.1uF
Simply RC Reset Circuit Diode Reset Circuit for Brownout Reset