R28 datasheet(51/473 Pages) RENESAS

51 / 473 page

R8C/28 Group, R8C/29 Group

6. Voltage Detection Circuit

Rev.2.10

Sep 26, 2008

Page 32 of 441

REJ09B0279-0210

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 (for N, D version only), voltage monitor 1 interrupt

(for N, D version only), voltage monitor 1 reset, voltage monitor 2 interrupt, and voltage monitor 2 reset can also be

used.

Tables 6.1 and 6.2 list the Specifications of Voltage Detection Circuit and Figures 6.1 to 6.6 show the Block Diagrams.

Figures 6.7 to 6.12 show the associated registers.

Table 6.1

Specifications of Voltage Detection Circuit (N, D Version)

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 rising

or 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 Vdet1

> VCC and VCC > Vdet1

when digital filter is

enabled;

interrupt request at Vdet1

> VCC or VCC > Vdet1

when digital filter is

disabled

Interrupt request at Vdet2

> VCC and VCC > Vdet2

when digital filter is

enabled;

interrupt request at Vdet2

> VCC or VCC > Vdet2

when digital filter is

disabled

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)

× 4

n: 1, 2, 4, and 8

(Divide-by-n of fOCO-S)

× 4

n: 1, 2, 4, and 8

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