
I-68
EPSON
S1C60N08 TECHNICAL HARDWARE
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (BLD Circuit)
4.14 Battery Life Detection (BLD) Circuit
4.14.1 Configuration of BLD circuit
The S1C60N08 Series has a built-in battery life detection (BLD) circuit, so that the software can find when
the source voltage lowers. The configuration of the BLD circuit is shown in Figure 4.14.1.1.
Also provides a heavy load protection function and an associated sub-BLD circuit. See Section 4.15,
"Heavy Load Protection Function and Sub-BLD Circuit".
Turning the BLD operation ON/OFF is controlled through the software (HLMOD, BLS). Moreover, when
a drop in source voltage (BLD0 = "1") is detected by the sub-BLD circuit, BLD operation is periodically
performed by the hardware until the source voltage is recovered (BLD0 = "0").
Because the power current consumption of the IC increases when the BLD operation is turned ON, set the
BLD operation to OFF unless otherwise necessary.
V
BLC2
BLC1
BLC0
BLD circuit
Evaluation
voltage
setting circuit
Detection output
Address 2E6H
Address 2FFH
BLS
BLD1
HLMOD
Data
bus
BLD
sampling
control
SS
VDD
Fig. 4.14.1.1 Configuration of BLD circuit
4.14.2 Programmable selection of evaluation voltage
In the S1C60N08 Series, the evaluation voltage for judging the battery life can be switched by program-
ming. Consequently, the optimum evaluation voltage can be set for the battery used.
One of eight evaluation voltages can be selected with the software. Table 4.14.2.1 lists the evaluation
voltages for the models in the S1C60N08 Series.
Table 4.14.2.1 Evaluation voltages for BLD circuit
S1C60N08
2.20
2.25
2.30
2.35
2.40
2.45
2.50
2.55
Register setting
Evaluation voltage (V)
BLC2
0
1
S1C60L08
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
BLC1
0
1
0
1
BLC0
0
1
0
1
0
1
0
1
S1C60A08
2.20
2.25
2.30
2.35
2.40
2.45
2.50
2.55
See the electrical characteristics for the evaluation voltage accuracy.