Datasheet

STM6321, STM6322, STM6821, STM6822, STM6823, STM6824, STM6825 Description
Doc ID 11110 Rev 12 7/31
1.1 Pin descriptions
1.1.1 Active low, push-pull reset output (RST) - 6823/6824/6825
Pulses low when triggered, and stays low whenever V
CC
is below the reset threshold or
when MR
is a logic low. It remains low for t
rec
after either V
CC
rises above the reset
threshold, the watchdog triggers a reset, or MR
goes from low to high.
1.1.2 Active low, open drain reset output (RST) - STM6321/6322/6822
Pulses low when triggered, and stays low whenever V
CC
is below the reset threshold or
when MR
is a logic low. It remains low for t
rec
after either V
CC
rises above the reset
threshold, the watchdog triggers a reset, or MR
goes from low to high. Connect a pull-up
resistor to supply voltage.
1.1.3 Push-button reset input (MR)
A logic low on MR asserts the reset output. Reset remains asserted as long as MR is low
and for t
rec
after MR returns high. This active low input has an internal 52 kΩ pull-up. It can
be driven from a TTL or CMOS logic line, or shorted to ground with a switch. Leave open if
unused.
1.1.4 Watchdog input (WDI)
If WDI remains high or low for at least 1.6 s, the internal watchdog timer expires and reset is
asserted. The internal watchdog timer clears while reset is asserted or when WDI sees
a rising or falling edge. The watchdog function CAN be disabled if WDI is left unconnected
or is connected to a tristate buffer output.
1.1.5 Active high reset output (RST)
Active high, push-pull reset output; inverse of RST.
Table 3. Pin functions
Pin
Name Function
STM6822
STM6823
STM6821
STM6321
STM6824
STM6322
STM6825
1—1 1RST
Active low reset output
33—4MR
Push-button reset input
4 4 4 — WDI Watchdog Input
— 1 3 3 RST Active high reset output
5555V
CC
Supply voltage
2222V
SS
Ground