HD6433694 Datasheet, PDF (304/432 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series

RES
Noise canceler
Noise canceler
φ
CK
PSS
R
OVF
R
Q
S
Power-on reset circuit
Internal reset
signal
Vcc
Ladder
resistor
Vreset
+
−
LVDRES
Vint
+
−
LVDINT
Reference
voltage
generator
Legend
PSS: Prescaler S
LVDCR: Low-voltage-detection control register
LVDSR: Low-voltage-detection status register
LVDRES: Low-voltage-detection reset signal
LVDINT: Low-voltage-detection interrupt signal
Vreset: Reset detection voltage
Vint:
Power-supply fall/rise detection voltage
LVDCR
Interrupt
control
circuit
LVDSR
Interrupt
request
Low-voltage detection circuit
Figure 18.1 Block Diagram of Power-On Reset Circuit and Low-Voltage Detection Circuit
18.2 Register Descriptions
The low-voltage detection circuit has the following registers.
• Low-voltage-detection control register (LVDCR)
• Low-voltage-detection status register (LVDSR)
18.2.1 Low-Voltage-Detection Control Register (LVDCR)
LVDCR is used to enable or disable the low-voltage detection circuit, set the detection levels for
the LVDR function, enable or disable the LVDR function, and enable or disable generation of an
interrupt when the power-supply voltage rises above or falls below the respective levels.
Table 18.1 shows the relationship between the LVDCR settings and select functions. LVDCR
should be set according to table 18.1.
Rev. 4.00, 03/04, page 276 of 400