Rainbow Electronics DS1615 User Manual

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DS1615

Temperature Recorde

FEATURES

 Digital thermometer measures temperature

-40°C to +85°C in 0.5°C increments (-40°F to +183.2°F in 0.9°F increments)

 Digital thermometer provides ±2°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

ORDERING INFORMATION

DS1615 16-Pin DIP DS1615S 16-Pin SOIC

PIN ASSIGNMENT

INSPEC

OUTSPEC

GND

BAT

INT

DS1615 16-Pin DIP (300 mil)

DS1615S 16-Pin SOIC (300 mil)

Top View

Package Dimension Information can be found at:

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

COMSEL

SCLK

I/O

RST

PIN DESCRIPTION

- Battery Supply

bat

X1 - Crystal Input X2 - Crystal Output NC - No Connect

INSPEC - In-specification Output OUTSPEC - Out-of-specification Output INT - Interrupt Output

GND - Ground

ST - Start/Status Input RST - 3-wire Reset Input

I/O - 3-wire Input/Output SCLK - 3-wire Clock Input TX - Transmit Output RX - Receive Input COMSEL - Communication Select V

- +5V Supply

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DS1615

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 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.

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DS1615 BLOCK DIAGRAM Figure 1

DS1615

SIGNAL DESCRIPTIONS

The following paragraphs describe the function of each pin.

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

connected to a +5-volts supply.

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

bat

exception of the serial interface circuitry are powered by V by VCC when VCC > V

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

bat

directly to GND.

GND - Ground

COMSEL (Communication Select Input) - This pin determines whether serial communication is

asynchronous or synchronous. When pulled high to V 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

< V

bat

when VCC< V

bat

, communication is synchronous and will take

. All functions are powered

bat

pin should be connected

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.

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DS1615

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.

ST (Start/Status Button Input) - The ST pin provides two functions. First, when enabled as the datalog

start source (SE bit in Control register is a logic 1), the ST pin is used to instruct the DS1615 to begin recording temperature data based on the programmed start delay and data sample rate. The ST 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 ST pin can be used to poll the status of the recorded data. After datalogging has begun, the

ST 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.

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DS1615 MEMORY MAP Figure 2a

Address Register Definition Page(s)

0000H 001FH 0020H 003FH 0040H 005FH 0060H 0217H 0218H 021FH 0220H 027FH 0280H

07FFH

0800H

087FH

0880H

0FFFH

1000H

17FFH

≥1800H

TEMPERATURE HISTOGRAM (63 BINS OF 2 BYTES EACH) 64 - 67

TEMPERATURE DATALOG MEMORY (64 PAGES) 128 - 191

RTC AND CONTROL REGISTERS 0

(RESERVED) 1

USER NV RAM 2

(RESERVED FOR FUTURE EXTENSIONS) 3 – 16*

SERIAL NUMBER 16**

ALARM TIME STAMPS AND DURATIONS 17 - 19

(RESERVED FOR FUTURE EXTENSIONS) 20 - 63

(RESERVED FOR FUTURE EXTENSIONS) 68 - 127

(RESERVED FOR FUTURE EXTENSIONS) 192 +

DS1615

* First 8 bytes ** Last 8 bytes

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DS1615 RTC AND CONTROL PAGE Figure 2b

ADDRESS BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0 FUNCTION

00 0 10 Seconds Single Seconds 01 0 10 Minutes Single Minutes

1002 0 12/24

A/P 03 0 0 0 0 0 Day Of Week 04 0 0 10 Date Single Date 05 0 0 0 10 m. Single Month 06 10 Years Single Years

07 MS 10 Seconds Alarm Single Seconds Alarm 08 MM 10 Minutes Alarm Single Minutes Alarm

10 h09 MH 12/24

A/P

0A MD 0 0 0 0 Day Of Week Alarm 0B Low Temperature Threshold

0C High Temperature Threshold 0D Number Of Minutes Between Temperature Conversions Sample Rate 0E

EOSC

CLR 0 SE RO TLIE THIE AIE

0F (reads 00h) Reserved 10 (reads 00h) Reserved 11 Current Temperature Temperature 12 Start Delay Register (LSB) Start Delay 13 Start Delay Register (MSB) Start Delay 14 TR MEM

MIP SIP LOBAT TLF THF ALMF Status

CLR 15 Minutes 16 Hours

17 Date 18 Month 19 Year

1A Low Byte 1B Medium Byte 1C High Byte

1D Low Byte 1E Medium Byte

1F High Byte

20-3F (Read 00H) Reserved

10 h Single Hours

10 h

Single Hours Alarm

alm

Real Time Clock

Registers

Real Time Alarm

Clock

Temperature

Alarm

Control

Start Time Stamp

Current Samples

Counter

Total Samples

Counter

DS1615

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DS1615 ALARM TIME STAMPS AND DURATIONS Figure 2c

DS1615

Sample Counter Address

(Low, Medium, High Bytes)

220, 221, 222 223 T1 Low 224, 225, 226 227 T2 Low 228, 229, 22A 22B T3 Low 22C, 22D, 22E 22F T4 Low 230, 231, 232 233 T5 Low 234, 235, 236 237 T6 Low 238, 239, 23A 23B T7 Low 23C, 23D, 23E 23F T8 Low 240, 241, 242 243 T9 Low 244, 245, 246 247 T10 Low 248, 249, 24A 24B T11 Low 24C, 24D, 243 24F T12 Low 250, 251, 252 253 T1 High 254, 255, 256 257 T2 High 258, 259, 25A 25B T3 High 25C, 25D, 25E 25F T4 High 260, 261, 262 263 T5 High 264, 265, 266 267 T6 High 268, 269, 26A 26B T7 High 26C, 26D, 26E 26F T8 High 270, 271, 272 273 T9 High 274, 275, 276 277 T10 High 278, 279, 27A 27B T11 High 27C, 27D, 27E 27F T12 High

Duration

Address

DS1615 HISTOGRAM MEMORY Figure 2d

Address (Low – High Byte) Register

800 – 801 -40, -39.5, -39, -38.5°C Data Bin 802 – 803 -38, -37.5, -37, -36.5°C Data Bin

804

↓

87B

87C – 87D 84, 84.5, 85°C Data Bin

↓

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DS1615

THERMAL SENSOR

The key to temperature monitoring in the DS1615 is an integrated thermal sensor. The thermal sensor can measure temperature from -40°C to +85°C in 0.5°C increments (Fahrenheit equivalent is -40°F to +183.2°F in 0.9°F increments). The thermal sensor provides an accuracy of ±2°C.

The format of temperature data is defined such that the temperature value is maintained in a single byte of data. Table 1 illustrates the format of the temperature data byte format. The values of T[7..0] range from 00000000b (for -40°C) to 11111010b (for 85°C). Each increment in the value of T[7..0] represents an increase in temperature of 0.5°C. The following formula can be used to translate the temperature data byte value into degrees Celsius: °C = 0.5(T[7..0]) - 40

TEMPERATURE DATA BYTE FORMAT Table 1

MSb LSb

T7 T6 T5 T4 T3 T2 T1 T0

When a datalog mission has been initiated, the DS1615 provides temperature recording at regular intervals. However, the device also allows for immediate temperature sensing upon a users command when the device is not currently on a datalog mission. This is accomplished by issuing the Read Temperature command to the DS1615 over the serial interface.

The most recently recorded temperature value is written to the Current Temperature register, regardless of whether that value was recorded from a datalog mission or from the issuance of the Read Temperature command. The status of the contents of this register is provided by the Temperature Ready (TR) bit in the Status register. If TR is a logic 1, the data is valid. If TR is a logic 0, the data may not be reliable. During a datalog mission, the TR bit is cleared to a logic 0 when a temperature conversion has been initiated and is set to a logic 1 upon the completion of the conversion. Likewise, the TR bit is cleared immediately after the Read Temperature command is issued and is set to a logic 1 upon the completion of the conversion.

DATA LOGGING

When the DS1615 datalogging function is enabled, the device is said to be on a datalog mission until the data-logging is stopped.

During a datalog mission, temperature samples are successively written to the Temperature Datalog memory pages. These memory pages are located at addresses 1000h to 17FFh. The first sample is written to address location 1000h. The second sample is written to address location 1001h. Likewise, the address is incremented with each additional data sample. A total of 2048 registers have been reserved for datalog data.

A datalog mission can be initiated via two different methods; by a host instruction over the serial interface or by a pushbutton input. When the SE bit in the Control register is cleared to a logic 0, the start

function of the ST pin is disabled and writing any non-zero value to the Sample Rate register will start a

mission. When the SE bit is set to a logic 1, the pushbutton method of starting a mission is enabled. Under this mode of operation, the DS1615 will begin a datalog mission when a non-zero value has been

written to the Sample Rate register and then the

The sample rate during a datalog mission is equal to the value written to the Sample Rate register multiplied by one minute. Writing a 0 to the MIP bit in the Status register completes the mission.

ST pin has been held low for at least 0.5 seconds.

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