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R8C/18 Group, R8C/19 Group
7.2
Voltage Monitor 1 Reset
Table 7.2 lists the Setting Procedure of Voltage Monitor 1 Reset Associated Bits and Figure 7.8 shows
an Operating Example of Voltage Monitor 1 Reset. To use voltage monitor 1 reset to exit stop mode, set
the VW1C1 bit in the VW1C register to 1 (digital filter disabled).
Table 7.2
Setting Procedure of Voltage Monitor 1 Reset Associated Bits
Step
1
Set the VCA26 bit in the VCA2 register to 1 (voltage detection 1 circuit enabled).
2
Wait for td(E-A)
Select the sampling clock of the digital filter
(1)
by bits VW1F0 to VW1F1 in the VW1C
3
register.
Set the VW1C1 bit in the VW1C register to 0
(1)
4
(digital filter enabled).
(1)
Set the VW1C6 bit in the VW1C register to 1 (voltage monitor 1 reset mode).
5
6
Set the VW1C2 bit in the VW1C register to 0.
7
Set the CM14 bit in the CM1 register to 0
(low-speed on-chip oscillator on).
8
Wait for 4 cycles of the sampling clock of the
digital filter.
9
Set the VW1C0 bit in the VW1C register to 1 (voltage monitor 1 reset enabled).
NOTE:
1. When the VW1C0 bit is set to 0 (disabled), steps 3, 4, and 5 can be executed simultaneously (with
1 instruction).
When the VW1C1 bit is set
to 0 (digital filter enabled).
When the VW1C1 bit is set
to 1 (digital filter disabled)
and the VW1C7 bit is set
to 1.
VW1C1 and VW1C7: Bits in VW1C register
Figure 7.8
Operating Example of Voltage Monitor 1 Reset
Rev.1.30
Apr 14, 2006
REJ09B0222-0130
When Using Digital Filter
VCC
Vdet1
(Typ. 2.85 V)
Sampling clock of
digital filter × 4 cycles
Internal reset signal
Internal reset signal
The above applies under the following conditions.
• VCA26 bit in VCA2 register = 1 (voltage detection 1 circuit enabled)
• VW1C0 bit in VW1C register = 1 (voltage monitor 1 reset enabled)
• VW1C6 bit in VW1C register = 1 (voltage monitor 1 reset mode)
When the internal reset signal is held "L", the pins, CPU and SFR are reset.
The internal reset signal level changes from "L" to "H", and a program is executed beginning with the address indicated by
the reset vector.
Refer to 4. Special Function Registers (SFRs), for the SFR status after reset.
Page 48 of 233
7. Voltage Detection Circuit
When Not Using Digital Filter
Set the VW1C7 bit in the VW1C register to 1.
Set the VW1C1 bit in the VW1C register to 1
(digital filter disabled).
−
− (No wait time)
fRING-S
fRING-S
1
× 32
1
× 32
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