DS1670 Datasheet, PDF (1/17 Pages) Dallas Semiconductor – Portable System Controller

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FEATURES
Provides real time clock:
− Counts seconds, minutes, hours, date of
the month, month, day of the week, and
year with leap year compensation valid up
to 2100
− Power control circuitry supports system
power-on from day/time alarm
Microprocessor monitor:
− Halts microprocessor during power fail
− Automatically restarts microprocessor
after power failure
− Monitors pushbutton for external override
− Halts and resets an out of control
microprocessor
NV RAM control:
− Automatic battery backup and write
protection to external SRAM
3-channel, 8-bit analog-to-digital converter
Simple 3-wire interface
3.3V operation
DS1670
Portable System Controller
PIN ASSIGNMENT
VBAT
1
VCCO
2
SCLK
3
I/O
4
CS
5
CEI
6
CEOL
7
CEOH
8
INT
9
GND
10
20 ST
19 V_CC
18 X1
17 X2
16 AIN0
15 AIN1
14 AIN2
13 ^RST
12 BLE
11 BHE
20-Pin TSSOP (4.4mm)
20-Pin SOIC (300 mil)
Package Dimension Information can be found at:
http://www.dalsemi.com/datasheets/mechdwg.html
ORDERING INFORMATION
DS1670E 20-pin TSSOP
DS1670S 20-pin SOIC
DESCRIPTION
The Portable System Controller is a circuit, which incorporates many of the functions necessary for low
power portable products integrated into one chip. The DS1670 provides a Real Time Clock, NV RAM
controller, microprocessor monitor, and a 3-channel, 8-bit analog-to-digital converter. Communication
with the DS1670 is established through a simple 3-wire interface.
The Real Time Clock (RTC) provides seconds, minutes, hours, day, date, month, and year information
with leap year compensation. The RTC also provides an alarm interrupt. This interrupt works when the
DS1670 is powered by the system power supply or when in battery backup operation so the alarm can be
used to wake up a system that is powered down.
Automatic backup and write protection of an external SRAM is provided through the V_CCO, CEOL , and
CEOH pins. The backup energy source used to power the RTC is also used to retain RAM data in the
absence of V_CC through the V_CCO pin. The chip-enable outputs to RAM ( CEOL and CEOH ) are
controlled during power transients to prevent data corruption.
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