m5295a Renesas Electronics Corporation., m5295a Datasheet - Page 4

• Manufacturer Part Number: m5295a
• Description: Watchdog Timer
• Manufacturer: Renesas Electronics Corporation.

M5295AL/AP/AFP
Operating Description
REJ03D0780-0200 Rev.2.00 Jun 15, 2007
Page 4 of 12
V
TC
V
RST1
RST2
(3), (4):
(6), (7):
(8), (9):
Terminology
t
t
t
RST(1)
WD
RST(2)
CC
IN
(10):
(11):
(1):
(2):
(5):
V
V
:
:
:
TH3(H)
TH3(L)
Time required for TC pin potential to rise from 0 V V
Time required for TC pin potential to rise from V
Time required for TC pin potential to go down from V
The V
charge of C1 begins.
The V
The voltage at TC pin is 2 V, then RST2 generates high, when 4 V, C1 is discharged and RST1
generates low.
The voltage at TC pin falls to 2 V, then RST1 generates high unless normal clock signal is entered
to WD pin, RST1 repeats this operation.
Before the voltage at TC pin reaches 4 V, if normal clock signal is entered to WD pin, low RST1 is
canceled.
In the case of entrance of abnormal signal input, as the waveform of TC pin repeats charge and
discharge of RST1 alternatively from 2 V to 4 V, the RST1 repeats high and low output operation.
The V
When V
potentional at TC pin is detected being V
0V
0V
0V
0V
0V
CC
CC
CC
V
t
RST(1)
V
TH2(H)
CC
TH1
rises up to 0.8 V, then RST1 and RST2 generates low output, and rising up to 4.25 V,
rises up to 4.7 V, then RST2 generates high.
falls to 4.6 V, then RST2 generates low, this detective voltage has a 100 mV hysteresis.
(1)
goes down to 4.25 V(V
(2)(3)
t
WD
(4) (5)
Figure 1 Operating Waveform
TH1
), the status of TC pin is switched to discharge. When the
t
TH3(H)
RST(2)
(6)
or V
TH3(L)
TH3(L)
TH3(L)
TH3(H)
(7) (8)
to V
, the status of RST1 becomes "low".
when V
TH3(H)
to V
TH3(L)
.
CC
is being applied.
.
(9)(10)(11)
V
V
TH2(L)
TH1