M16C28 Datasheet, PDF (56/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
5. Reset
Voltage Detection Register 1
b7 b6 b5 b4 b3 b2 b1 b0
0000 000
Symbol
VCR1
Address
001916
After Reset ⁽²⁾
000010002
Bit symbol
Bit name
F unction
RW
(b2-b0)
Reserved bit
Set to “0”
RW
VC13
Low voltage monitor flag ⁽¹⁾
0:VCC < Vdet4
1:VCC ≥ Vdet4
RO
(b7-b4)
Reserved bit
Set to “0”
RW
NOTES:
1. The VC13 bit is useful when the VC27 bit of VCR2 register is set to “1” (low voltage detection circuit enable).
The VC13 bit is always “1” (VCC≥ Vdet4) when the VC27 bit in the VCR2 register is set to “0” (low voltage
detection circuit disable).
2. This register does not change at software reset, watchdog timer reset and oscillation stop detection reset.
Voltage Detection Register 2 ⁽¹⁾
b7 b6 b5 b4 b3 b2 b1 b0
000000
Symbol
VCR2
Address
001A16
After Reset ⁽⁵⁾
0016
Bit Symbol
(b5-b0)
VC26
Bit Name
Reserved bit
Reset level monitor bit
(2, 3, 6)
Function
RW
Must set to “0”
RW
0: Disable reset level detection
circuit
1: Enable reset level detection
RW
circuit
VC27
Low voltage monitor
bit ^{(4, 6)}
0: Disable low voltage
detection circuit
1: Enable low voltage
RW
detection circuit
NOTES:
1. Write to this register after setting the PRC3 bit in the PRCR register to “1” (write enable).
2. When not in stop mode, to use hardware reset 2, set the VC26 bit to “1” (reset level detection circuit enable).
3. VC26 bit is disabled in stop mode. (The microcomputer is not reset even if the voltage input to Vcc pin becomes
lower than Vdet3.)
4. When the VC13 bit in the VCR1 register and D42 bit in the D4INT register are used or the D40 bit is set to “1”
(low voltage detection interrupt enable), set the VC27 bit to “1” (low voltage detection circuit enable).
5. This register does not change at software reset, watchdog timer reset and oscillation stop detection reset.
6. The detection circuit does not start operation until td(E-A) elapses after the VC26 bit or VC27 bit are set to “1”.
Figure 5.5 VCR1 Register and VCR2 Register
Rev. 2.00 Jan. 31, 2007 ^{page 36} of 385
REJ09B0047-0200