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R8C/38T-A Group
7. Voltage Detection Circuit
Under development Preliminary document
Specifications in this document are tentative and subject to change.
R01UH0241EJ0010 Rev.0.10
Page 74 of 730
Aug 05, 2011
Figure 7.7
Example of Voltage Monitor 2 Interrupt Operation
Vdet2
VW2C3
VCC
1.8 V
(1)
Digital filter
sampling clock
2 cycles
VW2C2
When VW2C1 bit is 1
(digital filter disabled),
VCAC2 bit is 0
(one edge),
and
VW2C7 bit is 0
(VCC reaches Vdet2 or above)
Set to 0 by acknowledgement
of an interrupt request
Digital filter
sampling clock
2 cycles
Set to 0 by a program
Voltage monitor 2 interrupt
request
Voltage monitor 2 interrupt
request
Set to 0 by acknowledgement
of an interrupt request
VW2C2
Voltage monitor 2 interrupt
request
When VW2C1 bit is 0
(digital filter enabled)
and
VCAC2 bit is 1 (both edges)
VW2C2
Set to 0 by acknowledgement
of an interrupt request
Set to 0 by a program
Voltage monitor 2 interrupt
request
When VW2C1 bit is 0
(digital filter enabled),
VCAC2 bit is 0
(one edge),
and
VW2C7 bit is 0
(VCC reaches Vdet2 or above)
VW2C2
Set to 0 by acknowledgement
of an interrupt request
Voltage monitor 2 interrupt
request
When VW2C1 bit is 0
(digital filter enabled),
VCAC2 bit is 0
(one edge),
and
VW2C7 bit is 1
(VCC reaches Vdet2 or below)
Set to 0 by a program
VW2C2
Voltage monitor 2 interrupt
request
When VW2C1 bit is 1
(digital filter disabled)
and
VCAC2 bit is 1 (both edges)
Set to 0 by a program
Set to 0 by acknowledgement
of an interrupt request
Set to 0 by a program
Set to 0 by acknowledgement
of an interrupt request
Set to 0 by a program
When VW2C1 bit is 1
(digital filter disabled),
VCAC2 bit is 0
(one edge),
and
VW2C7 bit is 1
(VCC reaches Vdet2 or below)
VW2C1 to VW2C3, VW2C7: Bits in VW2C register
VCAC2: Bit in VCAC register
The above diagram applies under the following conditions:
VCA27 bit in VCA2 register = 1 (voltage detection 2 circuit enabled)
VW2C0 bit in VW2C register = 1 (voltage detection 2 interrupt enabled)
Note:
1. If voltage monitor 0 reset is not used, VCC must be at least 1.8 V.