upd78f9211grt2-jjg-a ETC-unknow, upd78f9211grt2-jjg-a Datasheet - Page 201

• Manufacturer Part Number: upd78f9211grt2-jjg-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: ETC-unknow

14.4 Operation of Low-Voltage Detector
The low-voltage detector can be used in the following two modes.
• Used as reset
• Used as interrupt
The operation is set as follows.
(1) When used as reset
Compares the supply voltage (V
V
Compares the supply voltage (V
when V
DD
• When starting operation
<1> Mask the LVI interrupt (LVIMK = 1).
<2> Set the detection voltage using bits 3 to 0 (LVIS3 to LVIS0) of the low-voltage detection level select
<3> Set bit 7 (LVION) of LVIM to 1 (enables LVI operation).
<4> Use software to instigate a wait of at least 0.2 ms.
<5> Wait until “supply voltage (V
<6> Set bit 1 (LVIMD) of LVIM to 1 (generates internal reset signal when supply voltage (V
Figure 14-4 shows the timing of generating the internal reset signal of the low-voltage detector. Numbers <1>
to <6> in this figure correspond to <1> to <6> above.
Cautions 1. <1> must always be executed. When LVIMK = 0, an interrupt may occur immediately
• When stopping operation
< V
Either of the following procedures must be executed.
•
•
When using 8-bit memory manipulation instruction: Write 00H to LVIM.
When using 1-bit memory manipulation instruction: Clear LVIMD to 0 and LVION to 0 in that order.
DD
register (LVIS).
voltage (V
LVI
, and releases internal reset when V
< V
2. If supply voltage (V
LVI
.
after the processing in <3>.
signal is not generated.
LVI
)).
CHAPTER 14 LOW-VOLTAGE DETECTOR
DD
DD
) and detection voltage (V
DD
) and detection voltage (V
DD
) ≥ detection voltage (V
) ≥ detection voltage (V
User’s Manual U16994EJ3V0UD
DD
≥ V
LVI
.
LVI
LVI
LVI
)” at bit 0 (LVIF) of LVIM is confirmed.
LVI
), and generates an internal reset signal when
), and generates an interrupt signal (INTLVI)
) when LVIMD is set to 1, an internal reset
DD
) < detection
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