TC1232
3.0
PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1:
Pin No.
PIN FUNCTION TABLES
Buffer/
Pin
8-pin
Symbol
Driver
16-pin
Type
PDIP,
Type
SOIC
SOIC
1
2
PB RST
I
ST
Function
Push-button Reset Input.
Input for a Manual Reset Switch. This input debounces (ignores) pulses
less than 1 ms in duration and is ensured to recognize inputs of 20 ms or
greater.
L = Manual Reset Switch is Active, Force RST/RST pins Active
H = Manual Reset Switch is Inactive. State of RST/RST pins determined by
other system conditions.
Time Delay Input.
The voltage level on this input determines the watchdog timer time-out
period.
TD = 0V
t
TD
= 150 ms
TD = Open
t
TD
= 600 ms
TD = V
CC
t
TD
= 1.2 sec
Tolerance Input.
TOL = GND, Max Voltage Trip Point (V
CCTP
) = 4.75V (5% tolerance)
TOL = V
CC
, Max Voltage Trip Point (V
CCTP
) = 4.5V (10% tolerance)
The ground reference for the device.
Reset Output (Active-High)
Goes active (High) if one of these conditions occurs:
1. If V
CC
falls below the selected reset voltage threshold.
2. If PB RST pin is forced low.
3. If ST pin is not strobed within the minimum selected time-out period.
(see TD pin)
4. During power-up
Reset Output (Active-Low)
Goes active (Low) if one of these conditions occurs:
1. If V
CC
falls below the selected reset voltage threshold.
2. If PB RST pin is forced low.
3. If ST pin is not strobed within the minimum selected time-out period.
(see TD pin)
4. During power-up
Strobe Input
Input for Watchdog Timer. WDT period determined by state of TD pin
Falling Edge
Resets Watchdog Timer counter (no time-out)
The positive supply (+5V) for the device.
No internal connection.
2
4
TD
I
ST
3
6
TOL
I
ST
4
5
8
9
GND
RST
—
O
P
Push
Pull
6
11
RST
O
Open
Drain
7
13
ST
I
ST
8
—
15
1,3,5,
7,10,1
2,16
V
CC
NC
—
—
P
—
DS21370D-page 6
Preliminary
2002-2012 Microchip Technology Inc.
MICROCHIP [ MICROCHIP TECHNOLOGY ]
