UPD784218 Datasheet, PDF (55/92 Pages) NEC – 16-/8-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784218, 784218Y
12. RESET FUNCTION
When a low-level signal is input to the RESET pin, the system is reset, and each hardware unit is initialized (reset).
During the reset period, oscillation of the main system clock is unconditionally stopped. Consequently, the current
consumption of the entire system can be reduced.
When the RESET signal goes high, the reset status is cleared, the oscillation stabilization time (84.0 ms at 12.5
MHz operation) elapses, the contents of the reset vector table are set to the program counter (PC), execution
branches to an address set to the PC, and program execution is started from that branch address. Therefore, the
program can be reset and started from any address.
Figure 12-1. Oscillation of Main System Clock During Reset Period
Main system clock
oscillator
fCLK
Oscillation is unconditionally
stopped during reset period
RESET input
Oscillation stabilization time
The RESET input pin has an analog delay noise eliminator to prevent malfunctioning due to noise.
Figure 12-2. Acknowledgement of Reset Signal
Analog delay
Analog delay
Oscillation
Analog _{stabilization}
delay _time
RESET input
Internal reset signal
Internal clock
Data Sheet U12304EJ2V0DS00
55