R8C2H datasheet(59/67 Pages) RENESAS

59 / 67 page

R8C/2H Group, R8C/2J Group

6. Voltage Detection Circuit

Rev.1.00

Mar 28, 2008

Page 39 of 341

REJ09B0388-0100

Voltage Detection Circuit

The voltage detection circuit monitors the input voltage to the VCC pin. This circuit can be used to monitor the VCC

input voltage by a program. Alternately, voltage monitor 0 reset, voltage monitor 1 interrupt, voltage monitor 1 reset,

voltage monitor 2 interrupt, and voltage monitor 2 reset can also be used.

Note that voltage monitor 1 and voltage monitor 2 share the voltage detection circuit with comparator 1 and

comparator 2. Either voltage monitor 1 and voltage monitor 2 or comparator 1 and comparator 2 can be selected.

Table 6.1 lists the Specifications of Voltage Detection Circuit and Figures 6.1 to 6.4 show the Block Diagrams. Figures

6.5 to 6.10 show the Associated Registers.

Table 6.1

Specifications of Voltage Detection Circuit

Item

Voltage Detection 0

Voltage Detection 1

Voltage Detection 2

VCC Monitor

Voltage to monitor Vdet0

Vdet1

Vdet2

Detection target

Whether passing

through Vdet0 by falling

Passing through Vdet1 by

rising or falling

Passing through Vdet2 by

rising or falling

Monitor

None

VW1C3 bit in VW1C

VCA13 bit in VCA1

Whether VCC is higher or

lower than Vdet1

Whether VCC is higher or

lower than Vdet2

Process

When Voltage

is Detected

Reset

Voltage monitor 0 reset Voltage monitor 1 reset

Voltage monitor 2 reset

Reset at Vdet0 > VCC;

restart CPU operation at

VCC > Vdet0

Reset at Vdet1 > VCC;

restart CPU operation

after a specified time

Reset at Vdet2 > VCC;

restart CPU operation

after a specified time

Interrupt

None

Voltage monitor 1 interrupt Voltage monitor 2 interrupt

Interrupt request at both

or either of Vdet1 > VCC

and VCC > Vdet1

Interrupt request at both

or either of Vdet2 > VCC

and VCC > Vdet2

Digital Filter

Switch

enabled/disabled

Available

Sampling time

(Divide-by-n of fOCO-S)

× 4

n: 1, 2, 4, and 8

(Divide-by-n of fOCO-S)

× 2

n: 1, 2, 4, and 8

(Divide-by-n of fOCO-S)

× 2

n: 1, 2, 4, and 8

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