Specifications

I-64 EPSON S1C62N82 TECHNICAL HARDWARE
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (SVD Circuit and Heavy Load Protection Function)
Supply Voltage Detection (SVD) Circuit and
Heavy Load Protection Function
The S1C62N82 Series have a built-in supply voltage detec-
tion (SVD) circuit and a heavy load protection function.
Figure 4.9.1 shows the configuration of the circuit.
SVD circuit
The SVD circuit monitors the conditions of the supply
voltage (battery voltage), and software can check whether
the supply voltage has dropped below the detecting voltage
level of the SVD circuit: 2.4 V when supply voltage is 3.0 V
(S1C62N82), or 1.2 V when supply voltage is 1.5 V
(S1C62L82). Registers SVDON (SVD control on/off) and
SVDDT (SVD data) are used for the SVD circuit. The soft-
ware can turn SVD operation on and off. When SVD is on,
the IC draws a large current, so keep SVD off unless it is.
Heavy load protection function circuit
When using the S1C62N82, the melody, lamp, and other
features impose a heavy load on the battery. Therefore, a
heavy load protection function is incorporated in case of a
voltage drop. Software-initiated switching can be effected in
heavy load protection mode. The HLMOD register controls
the heavy load protection function. Conversely, when the
SVD circuit detects a voltage drop below 1.2 V (S1C62L82),
or 2.4 V (S1C62N82/62A82), switching to heavy load protec-
tion mode is carried out automatically.
This function enables 0.9 V operation (S1C62L82).
In the heavy load protection mode, the SVD circuit is acti-
vated intermittently by hardware. The cycle is 2 Hz and the
operating time is 122 µs (when the oscillation frequency,
fosc1, of the oscillation circuit is 32,768 Hz).
4.9
Configuration of SVD
circuit and heavy
load protection
function