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DS1302 RTC Pinout, Features, Datasheet

Author: Iggy
Date: 14 Oct 2020
 868
ds1302 applications

Description

DS1302 is a low-power real-time clock chip with trickle current charging capability. It can time the year, month, day, week, hour, minute, and second.

This Video Introduces DS1302 Arduino Realtime Clock

Catalog

Description

DS1302 Pinout

DS1302 Documents and Media

DS1302 CAD Models

DS1302 Parameters

DS1302 Features

DS1302 Advantage

DS1302 Applications

DS1302 Typical Operating Circuit

DS1302 Environmental and Export Classifications

DS1302 Block Diagram

How to Use DS1302

DS1302 RTC Module

DS1302 Command Byte

FAQ

Ordering & Quantity

DS1302 Pinout

The figure below shows the pin arrangement of DS1302. Among them, Vcc2 is the main power supply, and VCC1 is the backup power supply. The continuous operation of the clock can be maintained even when the main power is off. DS1302 is powered by the larger of Vcc1 or Vcc2. When Vcc2 is greater than Vcc1+0.2V, Vcc2 supplies power to DS1302. When Vcc2 is less than Vcc1, DS1302 is powered by Vcc1. X1 and X2 are the oscillation sources and an external 32.768kHz crystal oscillator. RST is the reset/chip select line. All data transfers are started by driving the RST input to high. RST input has two functions: First, RST turns on the control logic, allowing the address/command sequence to be sent to the shift register; second, RST provides a method to terminate single-byte or multi-byte data transmission. When RST is high, all data transfers are initialized, allowing operations on DS1302. If RST is set to a low level during the transfer, the data transfer will be terminated and the I/O pin will become high impedance. During power-on operation, RST must remain low before Vcc>2.0V. Only when SCLK is low, can RST be set high. I/O is a serial data input and output terminal (two-way), which will be described in detail later. SCLK is the clock input terminal.

ds1302 rtc pinout

Pin Number

Pin Name

Description

1

VCC2

Primary Power-Supply Pin in Dual Supply Configuration. VCC1 is connected to a

backup source to maintain the time and date in the absence of primary power. The

DS1302 operates from the larger of VCC1 or VCC2. When VCC2 is greater than VCC1 +

0.2V, VCC2 powers the DS1302. When VCC2 is less than VCC1, VCC1 powers the

DS1302.

2

X1

Connections for Standard 32.768kHz Quartz Crystal. The internal oscillator is

designed for operation with a crystal having a specified load capacitance of 6pF.

For more information on crystal selection and crystal layout considerations, refer to

Application Note 58: Crystal Considerations for Dallas Real-Time Clocks. The

DS1302 can also be driven by an external 32.768kHz oscillator. In this

configuration, the X1 pin is connected to the external oscillator signal and the X2 pin

is floated.

3

X2

4

GND

Ground

5

CE

Input. CE signal must be asserted high during a read or a write. This pin has an

internal 40kΩ (typ) pulldown resistor to ground. Note: Previous data sheet revisions

referred to CE as RST. The functionality of the pin has not changed.

6

I/O

Input/Push-Pull Output. The I/O pin is the bidirectional data pin for the 3-wire

interface. This pin has an internal 40kΩ (typ) pulldown resistor to ground.

7

SCLK

Input. SCLK is used to synchronize data movement on the serial interface. This pin

has an internal 40kΩ (typ) pulldown resistor to ground.

8

VCC1

Low-Power Operation in Single Supply and Battery-Operated Systems and LowPower Battery Backup. In systems using the trickle charger, the rechargeable

energy source is connected to this pin. UL recognized to ensure against reverse

charging current when used with a lithium battery.


DS1302 Documents and Media

Datasheets

DS1302

Other Related Documents

Tips for Writing Bulletproof Real-Time Clock Control Code

Mfg Application Notes

Estimating Super Capacitor Backup Time on Trickle-Charger Real-Time Clocks

Selecting a Backup Source for Real-Time Clocks

Oscillator Design Considerations for Low-Current Applications

State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks

Environmental Information

Halogen Certificate

Red Phosphorous Certificate

Material Declaration DS1302

PCN Obsolescence/ EOL

Mult Dev OBS 15/Jul/2015

HTML Datasheet

DS1302

EDA / CAD Models

DS1302 by SnapEDA

DS1302 by Ultra Librarian


DS1302 CAD Models

ds1302 symbol

DS1302 Symbol

ds1302 footprint

DS1302 Footprint


DS1302 Parameters

Base Product Number

DS1302

Battery Backup Switching

Backup Switching

Category

Integrated Circuits (ICs)

Clock/Timing - Real Time Clocks

Current - Timekeeping (Max)

0.3µA ~ 1µA @ 2V ~ 5V

Date Format

YY-MM-DD-dd

Features

Leap Year, NVSRAM, Trickle-Charger

Function

Calendar, Clock, NV Timekeeping RAM, Trickle Charger

Interface

3-Wire Serial

Manufacturer

Maxim Integrated

Maximum Operating Temperature

+ 70°C

Minimum Operating Temperature

0°C

Mounting Style

Through Hole

Operating Temperature

0°C ~ 70°C

Package

Tube

Package / Case

8-DIP (0.300", 7.62mm)           

Packaging

Tube

Part Status

Obsolete

Product Category

Real Time Clock

RoHS

N

RTC Bus Interface

Serial

RTC Memory Size

31 B

Subcategory

Clock & Timer ICs

Supplier Device Package

8-PDIP

Supply Voltage - Max

5.5 V

Supply Voltage - Min

2 V

Time Format

HH:MM:SS (12/24 hr)

Type

Clock/Calendar

Voltage - Supply, Battery

2V ~ 5.5V

 


DS1302 Features

  • Completely Manages All Timekeeping Functions

o 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

o 31 x 8 Battery-Backed General-Purpose RAM

  • Simple Serial Port Interfaces to Most Microcontrollers

o Simple 3-Wire Interface

o TTL-Compatible (VCC = 5V)

o Single-Byte or Multiple-Byte (Burst Mode) Data Transfer for Read or Write of Clock or RAM Data

  •  Low Power Operation Extends Battery Backup Run Time

o 2.0V to 5.5V Full Operation

o Uses Less Than 300nA at 2.0V

  • 8-Pin DIP and 8-Pin SO Minimizes Required Space
  • Optional Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
  • Underwriters Laboratories® (UL) Recognized

DS1302 Advantage

The DS1302 trickle-charge timekeeping chip contains a real-time clock/calendar and 31 bytes of static RAM. It communicates with a microprocessor via a simple serial interface. The real-time clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. Interfacing the DS1302 with a microprocessor is simplified by using synchronous serial communication. Only three wires are required to communicate with the clock/RAM: CE, I/O (data line), and SCLK (serial clock). Data can be transferred to and from the clock/RAM 1 byte at a time or in a burst of up to 31 bytes. The DS1302 is designed to operate on very low power and retain data and clock information on less than 1µW. The DS1302 is the successor to the DS1202. In addition to the basic timekeeping functions of the DS1202, the DS1302 has the additional features of dual power pins for primary and backup power supplies, programmable trickle charger for VCC1, and seven additional bytes of scratchpad memory.


DS1302 Applications

The applications of DS1302 include incorporated digital clocks/ timers of various modules in our real lives.

Other equivalents ICs of RTC are: DS1307, DS3231, DS3232


DS1302 Typical Operating Circuit

ds1302 typical operating circuit


DS1302 Environmental and Export Classifications

Attribute

Description

RoHS Status

RoHS non-compliant

Moisture Sensitivity Level (MSL)

1 (Unlimited)


How to Use DS1302

A typical operating circuit for DS1302 is given below. DS1302 have two power input, one is from cell and other is from controller. A crystal oscillator of 32.768 kHz is used to generate required frequency. For interfacing Data line, Reset Pin and Serial-clock pins of DS1302 are connected with the micro-controller.

da1302 circuit


DS1302 Block Diagram

ds1302 block diagram


DS1302 RTC Module

DS1302 is a tickle-charge timekeeping chip which contains a real-time clock/calendar and 31 bytes of static RAM. DS1302 uses serial communication to interact with microcontrollers. Also, it automatically adjust the date for the month with fewer days. Clock operates in 24hr or 12hr format with an AM/PM indicator.

DS1302 chip is also commonly used as DS1302 RTC module which comes with a 32 kHz crystal and on-board battery backup all in a small SIP module that is compatible with a breadboard. DS1302 module are used by makers with Arduino, Raspberry Pi and other Micro-controllers.

A DS1302 RTC module pinout is shown in below image.

ds1302 rtc module


DS1302 Command Byte

A command byte initiates each data transfer. The MSB (bit 7) must be a logic 1. If it is 0, writes to the DS1302 will be disabled. Bit 6 specifies clock/calendar data if logic 0 or RAM data if logic 1. Bits 1 to 5 specify the designated registers to be input or output, and the LSB (bit 0) specifies a write operation (input) if logic 0 or read operation (output) if logic 1. The command byte is always input starting with the LSB (bit 0).

ds1302 command byte


DS1302 Register

DS1302 has 12 registers, of which 7 registers are related to calendar and clock. The stored data bits are in the form of BCD codes. The calendar, time registers and their control words are shown in Table 1.

In addition, DS1302 also has year register, control register, charging register, clock burst register, and RAM-related registers. The clock burst register can read and write the contents of all registers except the charging register in sequence at one time. The DS1302 and RAM-related registers are divided into two categories: One is a single RAM unit, with 31 in total. Each unit is configured as an 8-bit byte, and its command control word is C0H~FDH. Among them, odd numbers are read operations, and even numbers are write operations; the other type is RAM registers in burst mode. In this mode, all 31 bytes of RAM can be read and written at once, and the command control words are FEH (write) and FFH (read).


FAQ

  • What is DS1302?

DS1302 is a tickle-charge timekeeping chip which contains a real-time clock/calendar and 31 bytes of static RAM. DS1302 uses serial communication to interact with microcontrollers. Also, it automatically adjust the date for the month with fewer days.

  • What does an RTC do?

A real-time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time. Although the term often refers to the devices in personal computers, servers and embedded systems, RTCs are present in almost any electronic device which needs to keep accurate time.

  • How do you use RTC?

Wiring It Up.
5V is used to power to the RTC chip when you want to query it for the time. If there is no 5V signal, the chip goes to sleep using the coin cell for backup.
Connect GND to common power/data ground.
Connect the SCL pin to the I2C clock SCL pin on your Arduino. ...
Connect the SDA pin to the I2C data SDA pin on your Arduino.

Ordering & Quality

Photo Mfr. Part # Company Description Package PDF Qty Pricing
(USD)
DS1302 DS1302 Company:Maxim Integrated Remark:Real Time Clock (RTC) IC Clock/Calendar 31B 3-Wire Serial 8-DIP (0.300", 7.62mm) Package:8-DIP (0.300"", 7.62mm)
DataSheet
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302 DS1302 Company:Maxim Integrated Remark:Timekeeper IC, Date Time Format (Day/Date/Month/Year hh:mm:ss), 3 Wire, Serial, 2 V to 5.5 V, DIP-8 Package:PDIP-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302N DS1302N Company:Maxim Integrated Remark:Trickle-Charge Timekeeping Chip Package:PDIP-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302N DS1302N Company:Maxim Integrated Remark:RTC IC, Date Time Format (Day/Date/Month/Year hh:mm:ss), Serial, 2 V to 5.5 V, DIP-8 Package:PDIP-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302S DS1302S Company:Maxim Integrated Remark:Trickle-Charge Timekeeping Chip Package:SOP8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302S DS1302S Company:Maxim Integrated Remark:RTC IC, Date Time Format (Date/Month/Year hh:mm:ss), Serial, 2 V to 5.5 V, SOIC-8 Package:SOP8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302S-T-R DS1302S-T-R Company:Maxim Integrated Remark:RTC IC, Date Time Format (Day/Date/Month/Year hh:mm:ss), Serial, 2 V to 5.5 V, WSOIC-8 Package:SOIC-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302S-16 DS1302S-16 Company:Maxim Integrated Remark:Trickle Charge Timekeeping Chip Package:SOIC-16
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302SN DS1302SN Company:Maxim Integrated Remark:Real Time Clock Trickle-Charge Timekeeping Chip Package:SOIC-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry
DS1302SN-T DS1302SN-T Company:Maxim Integrated Remark:Trickle Charge Timekeeping Chip Package:SOP-8
N/A
In Stock:On Order
Inquiry
Price:
Call
Inquiry

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