Instruction Manual

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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

 +3.0 or +5.0V operation

PIN ASSIGNMENT

Package Dimension Information can be found at:

http://www.dalsemi.com/datasheets/mechdwg.html

ORDERING INFORMATION

DS1673E - X 20-Pin TSSOP

DS1673S - X 20-Pin SOIC

3 +3V operation

5 +5V operation

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 DS1673 provides a Real Time Clock, NV RAM

controller, microprocessor monitor, and a 3-channel, 8-bit analog-to-digital converter. Communication

with the DS1673 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

DS1673 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.

DS1673

Portable System Controlle

www.dalsemi.com

BAT

CCO

SCLK

I/O

CEI

CEOL

CEOH

INT

GND

20-Pin TSSOP (4.4mm)

20-Pin SOIC (300 mil)

IN0

IN1

IN2

RST

BLE

BHE

Summary of content (18 pages)

PAGE 1
DS1673 Portable System Controller www.dalsemi.
PAGE 2
DS1673 Automatic backup and write protection of external SRAM is provided through the VCCO, CEOL , and CEOH pins. The backup energy source used to power the RTC is also used to retain RAM data in the absence of VCC through the VCCO pin. The chip enable outputs to RAM ( CEOL and CEOH ) are controlled during power transients to prevent data corruption. The microprocessor monitor circuitry of the DS1673 provides three basic functions.
PAGE 3
DS1673 SIGNAL DESCRIPTIONS VCC, GND - DC power is provided to the device on these pins. VCC is the +3.0 volt or +5.0 volt input. VBAT (Backup Power Supply) - Battery input for standard 3-volt lithium cell or other energy source. SCLK (Serial Clock Input) - SCLK is used to synchronize data movement on the serial interface. I/O (Data Input/Output) - The I/O pin is the bi-directional data pin for the 3-wire interface.
PAGE 4
DS1673 X1, X2 - Connections for a standard 32.768 kHz quartz crystal. For greatest accuracy, the DS1673 must be used with a crystal that has a specified load capacitance of 6 pF. There is no need for external capacitors or resistors. Note: X1 and X2 are very high impedance nodes. It is recommended that they and the crystal be guard-ringed with ground and that high frequency signals be kept away from the crystal area.
PAGE 5
DS1673 DS1673 ADDRESS MAP Figure 3 CLOCK, CALENDAR AND ALARM The time and calendar information is accessed by reading/writing the appropriate register bytes. Note that some bits are set to 0. These bits will always read 0 regardless of how they are written. Also note that registers 0Fh to 7Fh are reserved. These registers will always read 0 regardless of how they are written. The contents of the time, calendar, and alarm registers are in the Binary-Coded Decimal (BCD) format.
PAGE 6
DS1673 TIME OF DAY ALARM BITS Table 1 ALARM REGISTER MASK BITS (BIT 7) SECONDS MINUTES HOURS DAYS 1 1 1 1 0 1 1 1 0 0 1 1 0 0 0 1 0 0 0 0 Alarm once per second. Alarm when seconds match. Alarm when minutes and seconds match. Alarm when hours, minutes and seconds match. Alarm when day, hours, minutes and seconds match. SPECIAL PURPOSE REGISTERS The DS1673 has two additional registers (control register and status register) that control the Real Time Clock and interrupts.
PAGE 7
DS1673 STATUS REGISTER BIT 7 CU BIT 6 LOBAT BIT 5 0 BIT 4 0 BIT 3 0 BIT 2 0 BIT 1 0 BIT 0 IRQF CU (Conversion Update In Progress) - When this bit is a 1, an update to the ADC Register (register 0Eh) will occur within 488 µs. When this bit is a 0, an update to the ADC Register will not occur for at least 244 µs. LOBAT (Low Battery Flag) - This bit reflects the status of the backup power source connected to the VBAT pin. When VBAT is greater than 2.5 volts, LOBAT is set to a logic 0.
PAGE 8
DS1673 EXTERNAL SRAM INTERFACE (WORD-WIDE) TO THE DS1673 Figure 4 MICROPROCESSOR MONITOR The DS1673 monitors three vital conditions for a microprocessor: power supply, software execution, and external override. First, a precision temperature-compensated reference and comparator circuit monitors the status of VCC.
PAGE 9
DS1673 WATCHDOG TIME-OUT CONTROL Figure 5 WATCHDOG REGISTER BIT 7 BIT 6 BIT 5 0 0 0 WATCHDOG REGISTER TD1 TD0 0 0 0 1 1 0 1 1 BIT 4 0 BIT 3 0 BIT 2 0 BIT 1 TD1 BIT 0 TD0 WATCHDOG TIME-OUT WATCHDOG DISABLED 250 ms 500 ms 1000 ms ANALOG-TO-DIGITAL CONVERTER The DS1673 provides a 3-channel, 8-bit analog-to-digital converter. The A/D reference voltage (2.55V typical) is derived from an on-chip band-gap circuit. Three multiplexed analog inputs are provided through the AIN0, AIN1, and AIN2 pins.
PAGE 10
DS1673 CU BIT TIMING Figure 6 3-WIRE SERIAL INTERFACE Communication with the DS1673 is accomplished through a simple 3-wire interface consisting of the Chip Select (CS), Serial Clock (SCLK) and Input/Output (I/O) pins. All data transfers are initiated by driving the CS input high. The CS input serves two functions. First, CS turns on the control logic which allows access to the shift register for the address/command sequence.
PAGE 11
DS1673 SINGLE-BYTE DATA TRANSFER Figure 7 MULTIPLE-BYTE BURST TRANSFER Figure 8 11 of 18
PAGE 12
DS1673 ABSOLUTE MAXIMUM RATINGS* Voltage on Any Pin Relative to Ground Operating Temperature Storage Temperature Soldering Temperature -0.3V to +7.0V 0°C to 70°C -55°C to +125°C See J-STD-020A Specification * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.
PAGE 13
DS1673 (0°C to 70°C; VCC=3.0V ±=10%) DC ELECTRICAL CHARACTERISTICS PARAMETER SYMBOL MIN TYP Input Leakage ILI -1 CS Leakage ILO Logic 1 Output (IOUT =-0.4 mA) VOH 2.4 Logic 0 Output (IOUT = 1.5 mA) VOL Active Supply Current (CS=VCC -0.2) ICCA 0.75 A/D Converter Current IADC Standby Current (CS=VIL) ICCS Battery Current (Oscillator On) IBAT1 300 Battery Standby Current (Oscillator Off) IBAT2 35 47 RP Internal RST Pullup Resistor VCC Trip Point VCCTP 2.5 2.6 VCC Switchover VCCSW 2.30 2.
PAGE 14
DS1673 AC ELECTRICAL CHARACTERISTICS PARAMETER Data to Clock Setup CLK to Data Hold CLK to Data Delay CLK to Low Time CLK to High Time CLK Frequency CLK Rise and Fall CS to CLK Setup CLK to CS Hold CS Inactive Time CS to I/O High-Z VCC Slew Rate (4.5V to 2.3V) VCC Slew Rate (2.3V to 4.
PAGE 15
DS1673 AC ELECTRICAL CHARACTERISTICS PARAMETER Data to Clock Setup CLK to Data Hold CLK to Data Delay CLK to Low Time CLK to High Time CLK Frequency CLK Rise and Fall CS to CLK Setup CLK to CS Hold CS Inactive Time CS to I/O High-Z VCC Slew Rate (2.7V to 2.3V) VCC Slew Rate (2.3V to 2.
PAGE 16
DS1673 TIMING DIAGRAM: READ DATA Figure 9 TIMING DIAGRAM: WRITE DATA Figure 10 16 of 18
PAGE 17
DS1673 PUSHBUTTON RESET Figure 11 POWER-UP Figure 12 POWER-DOWN Figure 13 17 of 18
PAGE 18
DS1673 NOTES: 1. All voltages are referenced to ground. 2. Logic 1 voltages are specified at VCC=3.0V, VOH=VCC for capacitive loads. Excludes 3. Logic 0 voltages are specified at VCC=3.0, VOL=GND for capacitive loads. 4. ICCA is specified with outputs open, CS set to a logic 1, SCLK=500 kHz, oscillator enabled, and D/A converter enabled. 5. IADC is specified with CS, VCCO open and I/O, SCLK at logic zero. A/D converter is enabled. 6.