M32C8A Datasheet, PDF (54/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
6. Power Supply Voltage Detection Function
6. Power Supply Voltage Detection Function
The power supply voltage detection function has the Vdet3 detection function, Vdet4 detection function, and cold
start/warm start determination function. The Vdet3 detection function and Vdet4 detection function detect the changes
in voltage and trigger the events. The cold start/warm start determination function determines whether the MCU is
reset at power-on or reset while running.
The power supply voltage detection function is available only with VCC1 = 4.2V to 5.5V standard.
Figure 6.1 shows a block diagram of the voltage detection circuit. Figures 6.2 to 6.4 show voltage detection-associated
registers.
Vdet3 detection fucntion
VCC1
VC26
CM10
＋
≥Vdet3
E
1 shot
TQ
Wait time to release hardware reset 2:
td(S-R)
Internal reset signal
(active "L")
CPU clock
Vdet4 detection function
VC27
＋
≥Vdet3
E
VC13
Analog Filter
(rejection range: 200 ns)
Vdet4 detection signal⁽¹⁾
DF1 to DF0
00b
01b
10b
1/8
1/2
1/2
1/2 ^11b
Digital filter
D42 bit
CM10
WAIT instruction (wait mode)
Latch
D41
Cold start/warm start determination function
Output one-shot pulse when the
D42 bit becomes 0 to 1.
Vdet4 detection
interrupt signal
D40
Oscillation stop
detection
interrupt signal
Watchdog timer
interrupt signal
Write a given value to
the WDC register
WDC5
SQ
COLD/WARM
(Cold start, warm start)
Hardware reset 1
at power-on
R
Watchdog timer
interrupt request
CM10: bit in the CM1 register
VC13: bit in the VCR1 register
VC26, VC27: bits in the VCR2 register
DF1 and DF0, D40, D41, D42: bits in the D4INT register
WDC5: bit in the WDC register
NOTE:
1. When the VC27 bit in the VCR2 register is set to 0 (Vdet4 detection function not used), the Vdet4 detection signal becomes "H".
Figure 6.1 Power Supply Voltage Detection Function Block Diagram
Rev.1.00 Jul 15, 2007 Page 37 of 352
REJ09B0385-0100