NEC PD754144 - Manual (Page 227)

227 User’s Manual U10676EJ3V0UM
CHAPTER 9 RESET FUNCTION
9.1 Configuration and Operation of Reset Function
Three types of reset signals are used: the external reset signal (RESET), a reset signal from the basic interval
timer/watchdog timer, and a key return reset. When any one of these reset signals is input, the internal reset signal
is asserted. Figure 9-1 shows the configuration of the reset circuit.
Figure 9-1. Configuration of Reset Circuit
V
DD
Mask option
KRREN
RESET
Q R
S
Q S
R
Q S
R
Instruction
STOP mode
KRF
WDF
Watchdog timer overflow
Internal reset signal
Instruction
One-shot pulse generator
V
DD
Mask option
P70/KR4
P71/KR5
P72/KR6
P73/KR7
Internal bus
Falling edge detector
Interrupt
When the RESET signal is generated, each hardware unit is initialized as shown in Table 9-1. Figure 9-2 shows
the timing of the reset operation.