HD64336900G Datasheet, PDF (297/408 Pages) Renesas Technology Corp – 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Tiny Series

External
power
supply
Noise filter
circuit
Noise filter
circuit
Vcc
Ladder
network
Vreset
VintU
VintD
φ _CK
OVF
PSS
R
R
Q
S
Internal
reset signal
Power-on reset circuit
LVDCR
ExtD
ExtU
Interrupt
control
circuit
VDDII
VBGR
[Legend]
PSS:
LVDCR:
LVDSR:
VBGR:
ExtD:
ExtU:
VDDII:
Prescaler S
Low-voltage-detection control register
Low-voltage-detection status register
Reference voltage from BGR
Compared voltage for falling external input voltage
Compared voltage for rising external input voltage
Bit 5 in LVDCR
LVDSR
Interrupt request
Figure 17.2 Block Diagram of Power-On Reset Circuit and Low-Voltage Detection Circuit
17.2 Register Descriptions
The low-voltage detection circuit has the following registers.
• Low-voltage-detection control register (LVDCR)
• Low-voltage-detection status register (LVDSR)
17.2.1 Low-Voltage-Detection Control Register (LVDCR)
LVDCR enables or disables the low-voltage detection circuit and BGR circuit, selects the
compared voltage of the LVDI circuit, sets the detection levels for the LVDR circuit, enables or
disables the LVDR circuit, and enables or disables generation of an interrupt when the power-
supply voltage rises above or falls below the respective levels.
Table 17.1 shows the relationship between the LVDCR settings and functions to be selected.
LVDCR should be set according to table 17.1.
Rev. 1.00, 11/03, page 269 of 376