1 of 24

052400

FEATURES

Digital thermometer measures temperature
-40

C to +85

C in 0.5

C increments (-40

to +183.2

F in 0.9

F increments)

Digital thermometer provides

C accuracy

Real Time Clock/Calendar in BCD format
counts seconds, minutes, hours, date, month,
day of the week, and year with leap year
compensation (Y2K compatible)

Automatically wakes up and measures
temperature at user-programmable intervals
from 1 to 255 minutes

Logs up to 2048 consecutive temperature
measurements in read-only nonvolatile
memory

Records long-term temperature histogram in
63 bins with 2.0

C resolution

Programmable temperature-high and
temperature-low alarm trip points

Two serial interface options: synchronous and

asynchronous
- 3-wire synchronous serial interface
- Asynchronous serial interface compatible

with standard UARTs

Memory partitioned into 32-byte pages for
packetizing data

On-chip 16-bit CRC generator to safeguard
data read operations in asynchronous
communications mode

Unique, factory lasered and tested 64-bit
serial number

PIN ASSIGNMENT

PIN DESCRIPTION

bat

- Battery Supply

X1 -

Crystal

Input

- Crystal Output

- No Connect

INSPEC

In-specification

Output

OUTSPEC

- Out-of-specification Output

INT

Interrupt

Output

GND -

Ground

Start/Status

Input

RST

- 3-wire Reset Input

I/O -

3-wire

Input/Output

SCLK

- 3-wire Clock Input

- Transmit Output

RX -

Receive

Input

COMSEL

- Communication Select

- +5V Supply

DS1615

Temperature Recorder

www.dalsemi.com

COMSEL

SCLK

I/O

RST

BAT

INSPEC

OUTSPEC

INT

GND

DS1615 16-Pin DIP

DS1615S 16-Pin SOIC (300 mil)

Top View

BUMP 1

BUMP 5

BUMP 17

BUMP 21

DS1615X Flip Chip Package

Bottom View

DS1615

2 of 24

ORDERING INFORMATION

DS1615 16-Pin DIP
DS1615S 16-Pin SOIC

DS1615S 16

-Pin SOIC

DS1615X Flip Chip Package

**For more information of Flip Chip Packaging, go to

www.dalsemi.com

to the Released Data Sheets

section and select

Chip Scale and Flip Chip Package Data Index.

DESCRIPTION

The DS1615 is an integrated temperature recorder that combines a real time clock with temperature data
logging and histogram capabilities. It has been designed for applications that require temperature
profiling over a given period of time. A programmable sampling rate feature makes the device ideal for
applications requiring temperature monitoring over short or long time frames. The integrated Real Time
Clock (RTC) provides seconds, minutes, hours, day, date, month, and year information with leap year
compensation and also provides an alarm interrupt. Temperature measurement is provided via integrated
thermal technology which can measure temperatures from -40

C to +85

C in 0.5

C increments.

The DS1615 is a powerful data recording device, providing both a datalog of sampled temperature values
over time and a histogram of temperature. The datalog function simply samples the temperature at a user
defined sample rate and writes the data to the Temperature Datalog memory. Up to 2048 datalog samples
may be recorded. Histogram functionality is implemented by sampling the temperature and then
incrementing the count value in a data bin associated with that temperature. The DS1615 provides
63, 2-byte data bins in 2

C increments. The user can program data sampling for both data logging and for

histogram tabulation at intervals ranging from once per minute to once every 255 minutes.

The DS1615 also supports programmable high and low temperature alarm trip points that allow the
device to monitor whether the temperature stays within desired limits. The device can drive an interrupt
or status pin if the temperature falls outside of the programmable limits. The DS1615 can be
programmed to begin sampling data via a pushbutton input or via a command sent over the serial
interface with a host machine.

The DS1615 also provides a 64-bit serial number which is useful for product identification and tracking.

OVERVIEW

The block diagram in Figure 1 shows the relationship between the major control and memory sections of
the DS1615. The device has five major data components: 1) Real Time Clock and control block, 2)
32-byte User NV RAM with 64-bit lasered serial number, 3) 96 bytes of Alarm event/duration memory,
4) 128 bytes of histogram RAM, and 5) 2048 bytes of datalog memory. All memory is arranged in a
single linear address space.

DS1615

3 of 24

DS1615 BLOCK DIAGRAM Figure 1

SIGNAL DESCRIPTIONS

The following paragraphs describe the function of each pin.

- V

is a +5V input supply. Communication with the DS1615 can take place only when V

connected to a +5V supply.

bat

Battery input for standard lithium cell or other energy source. All functions of the DS1615 with the

exception of the serial interface circuitry are powered by V

bat

when V

< V

bat

. All functions are powered

by V

when V

> V

bat

. If a battery or other energy source is not used, the V

bat

pin should be connected

directly to GND.

GND - Ground

COMSEL (Communication Select Input) - This pin determines whether serial communication is
asynchronous or synchronous. When pulled high to V

, communication is synchronous and will take

place via the SCLK, I/O, and

RST

pins. When COMSEL is tied to ground, asynchronous communication

utilizing the TX and RX pins is selected. If this pin is floated, the DS1615 will operate in the
asynchronous communications mode since the COMSEL pin has a weak internal pulldown resistor.

Tx (Transmit Output) -

Transmit output of the asynchronous serial interface. Tx is tri-stated whenever

< V

bat

Rx (Receive Input) -

Receive input of the asynchronous serial interface.

SCLK (3-wire Serial Clock Input) - The SCLK pin is

the serial clock input for the 3-wire synchronous

communications channel.

DS1615

4 of 24

I/O (3-wire Input/Output)

The I/O pin is the data

Input/Output signal for the 3-wire synchronous

communications channel.

RST

(3-wire Reset Input) - The

RST

pin is the communications reset pin for the 3-wire synchronous

communications channel.

INT

(Interrupt Output) -

The

INT

pin is an open drain active low output that can be connected to an

interrupt input of a microprocessor. The

INT

output remains low as long as the status bit causing the

interrupt is present and the corresponding interrupt-enable bit is set.

INSPEC

(Open Drain In-Specification Output) - This

pin, in conjunction with the

OUTSPEC

pin, is

used to signal the status of the operation and data of the DS1615.

OUTSPEC

(Open Drain Out-of-Specification Out-put) - This pin, in conjunction with the

INSPEC

pin,

is used to signal the status of the operation and data of the DS1615.

(Start/Status Button Input) - The

pin provides

two functions. First, when enabled as the datalog

start source (SE bit in Control register is a logic 1), the

pin is used to instruct the DS1615 to begin

recording temperature data based on the programmed start delay and data sample rate. The

pin must

be held low for at least 0.5 seconds for a datalog mission to begin. An external pullup resistor should be
connected to this pin.

Secondly, the

pin can be used to poll the status of the recorded data. After datalogging has begun, the

pin instructs the DS1615 to report the status of the recorded data via the

INSPEC

and

OUTSPEC

pins.

X1, X2 -

Connections for a standard 32.768 kHz quartz crystal, Daiwa part number DT-26S or

equivalent. For greatest accuracy, the DS1615 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. For more information on crystal selection and
crystal layout considerations, please consult Application Note 58, Crystal Considerations with Dallas
Real Time Clocks.

NC (No Connect) -

This pin should be left unconnected.

MEMORY

The memory map in Figure 2a shows the general organization of the DS1615. As can be seen in the
figure, the device is segmented into 32 byte pages. Pages 0 and 1 contain the Real Time Clock and
Control registers (see Figure 2b for more detail). The User NV RAM resides in page 2. Pages 17 to 19
are assigned to storing the alarm time stamps and durations. The temperature histogram bins begin at
page 64 and use up four pages. The temperature logging memory covers pages 128 to 191. Memory
pages 1, 3 to 16, 20 to 63, 68 to 127, and 192 and up are reserved for future extensions.

The end user can write only to the Real Time Clock and Control registers and the User NV RAM. The
rest of the memory map is read-only from the end users perspective.

DS1615

5 of 24

DS1615 MEMORY MAP Figure 2a

ADDRESS

0000H

TO 001FH

RTC AND CONTROL REGISTERS

PAGE 0

0020H

TO 003FH

(RESERVED)

PAGE 1

0040H

TO 005FH

USER NV RAM

PAGE 2

0060H

TO 0217H

(RESERVED FOR FUTURE EXTENSIONS)

PAGE 3

TO PAGE 16

(EXCLUDING LAST

8 BYTES OF

PAGE 16)

0218H

TO 021FH

SERIAL NUMBER

PAGE 16

(LAST 8 BYTES)

00220H

TO 027FH

ALARM TIME STAMPS AND DURATIONS

PAGE 17

TO PAGE 19

0280H

TO 07FFH

(RESERVED FOR FUTURE EXTENSIONS)

PAGES 20 - 63

0800H

TO 087FH

TEMPERATURE HISTOGRAM (63 BINS OF 2 BYTES EACH)

PAGE 64

TO PAGE 67

0880H

TO 0FFFH

(RESERVED FOR FUTURE EXTENSIONS)

PAGES 68 - 127

1000H

TO 17FFH

TEMPERATURE DATALOG MEMORY (64 PAGES)

PAGE 128

TO PAGE 191

1800H

AND HIGHER

(RESERVED FOR FUTURE EXTENSIONS)

PAGE 192 AND

HIGHER

Part Number DS1615