hd64338023s Renesas Electronics Corporation., hd64338023s Datasheet - Page 478

• Manufacturer Part Number: hd64338023s
• Description: Renesas 8-bit Single-chip Microcomputer Super Low Power Series
• Manufacturer: Renesas Electronics Corporation.

Section 14 Power-On Reset and Low-Voltage Detection Circuits (H8/38124 Group Only)
14.1.2
A block diagram of the power-on reset circuit and low-voltage detection circuit are shown in
figure 14.1.
Rev. 7.00 Mar 10, 2005 page 436 of 652
REJ09B0042-0700
External
External
resistor
supply
power
ladder
reference voltage
Two pairs of detection levels for reset generation voltage are available: when only the LVDR
circuit is used, or when the LVDI and LVDR circuits are both used. In addition, power supply
rise/drop detection voltages and a detection voltage reference voltage may be input from an
external source, allowing the detection level to be set freely by the user.
Figure 14.1 Diagram of Power-On Reset Circuit and Low-Voltage Detection Circuit
generator
External
Block Diagram
extD
extU
Vref
RES
Vcc
[Legend]
PSS:
LVDCR:
LVDSR:
LVDRES:
LVDINT:
Vreset:
Vint:
extD:
extU:
Vref:
Prescaler S
Low-voltage-detection control register
Low-voltage-detection status register
Low-voltage-detection reset signal
Low-voltage-detection interrupt signal
Reset detection voltage
Power-supply fall/rise detection voltage
Power supply drop detection voltage input pin
Power supply rise detection voltage input pin
Reference voltage input pin
resistor
Ladder
Vint
Vreset
reference voltage
generator
On-chip
canceler
canceler
Noise
Noise
+
+
−
−
LVDRES
LVDINT
φ
Interrupt
control
circuit
CK
R
PSS
Low-voltage detection circuit
Power-on reset circuit
OVF
LVDCR
LVDSR
R
S
Q
Interrupt
request
Internal reset
signal