H83802_10 Datasheet, PDF (389/546 Pages) Renesas Technology Corp – Renesas 8-Bit Single-Chip Microcomputer H8 Family / H8/300L Super Low Power Series

Section 14 Power-On Reset and Low-Voltage Detection Circuits (H8/38104 Group Only)
Procedures for Clearing Settings when Using LVDR and LVDI:
To operate or release the low-voltage detection circuit normally, follow the procedure described
below. Figure 14.7 shows the timing for the operation and release of the low-voltage detection
circuit.
1. To operate the low-voltage detection circuit, set the LVDE bit in LVDCR to 1.
2. Wait for 150 μs (t_LVDON) until the reference voltage and the low-voltage-detection power supply
have stabilized, based on overflow of LVDNT. Then, clear the LVDDF and LVDUF bits in
LVDSR to 0 and set the LVDRE, LVDDE, and LVDUE bits in LVDCR to 1, as required.
3. To release the low-voltage detection circuit, start by clearing all of the LVDRE, LVDDE, and
LVDUE bits to 0. Then clear the LVDE bit to 0. The LVDE bit must not be cleared to 0 at the
same timing as the LVDRE, LVDDE, and LVDUE bits because incorrect operation may occur.
LVDE
LVDRE
LVDDE
LVDUE
t_LVDON
Figure 14.7 Timing for Operation/Release of Low-Voltage Detection Circuit
Rev. 7.00 Mar. 08, 2010 Page 357 of 510
REJ09B0024-0700