UPD784915B Datasheet, PDF (60/86 Pages) NEC – 16-BIT SINGLE-CHIP MICROCONTROLLERS

µPD784915B, 784916B
4.4 Reset Function
When a low-level signal is input to the RESET pin, the system is reset, and each hardware unit is initialized (reset
status). During the reset period, oscillation of the system clock is unconditionally stopped, so that the current
dissipation of the overall system can be reduced.
When the RESET pin goes high, the reset status is cleared. After the count time of the oscillation stabilization timer
(32.8 ms at 16 MHz or 65.6 ms at 8 MHz) has elapsed, the contents of the reset vector table are set to the program
counter (PC), and execution branches to the address set to the PC, and the program is executed starting from the
branch destination address. Therefore, execution can be reset and started from any address.
Figure 4-7. Oscillation of Main System Clock during Reset Period
Main system clock
oscillation circuit
fCLT
During reset, oscillation
is unconditionally stopped.
RESET input
Oscillation stabilization
timer count time
The RESET pin is provided with an analog delay noise elimination circuit to prevent malfunctioning due to noise.
Figure 4-8. Accepting Reset Signal
Analog delay Analog delay
Oscillation
Analog stabilization
delay time
RESET input
Internal reset signal
Internal clock
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