SMR101
Preliminary Information
1
(See Last Page)
FEATURES & APPLICATIONS
•
Two Programmable Reset Outputs, SOFT_RST#
And HARD_RST#
•
De-Bounced Push-Button Reset Input With a
Programmable Delay Up To 40 Seconds Prior To
Reset Assertion
•
8 Programmable Settings For Both SOFT_RST#
And HARD_RST# Delay
•
Programmable Voltage Monitor With 8 Voltage
Settings To Trigger SOFT_RST# Output
•
Programmable Reset Output Duration From 1-
200ms
•
Built-In 15us Voltage Glitch Filtering And Input
“De-Bouncing”
TM
•
6 Ball
Ultra
CSP (Chip-Scale) Package
•
8 Lead SOIC Package
Applications
•
PDAs, Handheld PCs, Cameras, Camcorders
•
Handheld GPS Equipment
•
Satellite And Cable-TV Set-Top Box
INTRODUCTION
The SMR101 is a programmable reset controller
especially
designed
for
embedded
consumer
electronics. The device provides dual outputs that can
be used to implement “soft” and “hard” system resets.
Both resets can be triggered by an external reset input,
and an internal voltage monitor can trigger the soft
reset. Typically a “soft” reset applies to volatile registers
in an embedded controller while a hard reset is
equivalent to a full power cycle without the associated
power-up delays. The SMR101 receives an external
push-button input using an internal programmable de-
bounced timer. The push button input hold down time is
programmable up to 40 seconds with an internal on-chip
timer. A “short” hold down time (0.125-10 sec) asserts
the SOFT_RST# pin while a long hold down time (0.5-
40 sec) asserts the HARD_RST# pin. Both reset
outputs have programmable output durations from 1-
200ms. Additionally, voltage monitoring is provided via a
programmable threshold detector (2.30V – 4.50V) on
the VDD pin.
This voltage detector asserts the
SOFT_RST# pin for the same 1-200ms output duration
as above. A 15us glitch filter avoids nuisance tripping
that can result in unnecessary system resets. The
SMR101 is factory programmed, to default values;
however, multiplexed programming pins are also
provided for in-system programming for prototype
purposes.
SIMPLIFIED APPLICATIONS DRAWING
2.7V
_
5.5V
Manual
Reset
Switch
RESET_IN#
0.1μf
VDD
3.3V
TRIM_C
AP
FILT_CAP
SOFT_RST#
SMR101
HARD_RST#
PROG
GND
μP
Figure 1 – Applications schematic using the SMR101 to supervise an embedded controller. As shown, the
SMR101 implements a two-level RESET function including external manual input.
© SUMMIT
Microelectronics, Inc. 2006 •
757 North Mary Avenue • Sunnyvale CA 94085 • Phone 408 523-1000 • FAX 408 523-1266
http://www.summitmicro.com
2099 2.4 7/20/2010
1
SUMMIT [ SUMMIT MICROELECTRONICS, INC. ]
