DS1921H-F5 DALLAS [Dallas Semiconductor], DS1921H-F5 Datasheet
DS1921H-F5
Related parts for DS1921H-F5
DS1921H-F5 Summary of contents
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SPECIAL FEATURES* § Digital thermometer measures temperature in 0.5°C increments (accuracy ±1.0°C) § Built-in real-time clock (RTC) and timer has accuracy of ±2 minutes per month from 0°C to 45°C § Automatically wakes up and measures tem- perature at ...
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DESCRIPTION The DS1921L Thermochron iButtons are rugged, self-sufficient systems that measure temperature and record the result in a protected memory section. The recording is done at a user-defined rate, both as a direct storage of temperature values as well ...
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... The next 36 bits are a unique serial number. The next 12 bits, called temperature range code, allow distinguishing the various DS1921L-F5 versions from each other and from the DS1921H and DS1921Z. The last eight bits are a CRC of the first 56 bits. See Figure 3 for details. The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and XOR gates as shown in Figure 4 ...
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... CRC Code Range Code MSB LSB MSB DEVICE TEMP. RANGE (°C) DS1921L-F51 -10 to +85 DS1921L-F52 -20 to +85 DS1921L-F53 -30 to +85 DS1921L-F50 -40 to +85 DS1921H-F5 +15 to +46 DS1921Z- +26 1-Wire net DS1921 Available Cmd. Commands: Codes: Read ROM 33h Match ROM 55h Search ROM F0h Skip ROM ...
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CRC GENERATOR Figure STAGE STAGE STAGE MEMORY The memory map of the DS1921L is shown in Figure 5. The 4096-bit general-purpose SRAM make up pages 0 ...
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DS1921L REGISTER PAGE MAP Figure 6 ADDRESS RANGE ACCESS TYPE* 0200h to 0206h R/W; R** 0207h to 020Ah R/W; R** 020Bh R/W; R** 020Ch R/W; R** 020Dh R/W; R** 020Eh R/W; R** 020Fh to 0210h 0211h 0212h to 0213h R/W; ...
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RTC/Calendar The RTC of the DS1921L can run in either 12-hour or 24-hour mode. Bit 6 of the Hours Register (address 202h) is defined as the 12- or 24-hour mode select bit. When high, the 12-hour mode is selected. In ...
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If a temperature conversion yields a temperature that is out-of-range, it will be recorded as 00h (if too low) or FAh (if too high). Since out-of-range results are accumulated in histogram bins 0 and 62 (see section Temperature Logging and ...
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Control Register Bitmap ADDR b7 b6 020Eh EMCLR EOSC The functional assignments of the individual bits are explained in the table below. Bit 5 has no function. It always reads 0 and cannot be written to 1. Control Register Details ...
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Status Register The Status Register holds device status information and alarm flags. The register is located at address 214h. Writing to this register will not necessarily end a mission. Status Register Bitmap ADDR b7 b6 0214h TCB MEMCLR The functional ...
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Mission Time Stamp When a mission is started, a copy of the RTC Registers addresses 0201h, 0202h, and 0204h to 0206h is saved as the Mission Time Stamp. The Mission Time Stamp does not indicate the time of the first ...
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There are two alternatives to the way the DS1921L will behave after the 2048 bytes of datalog memory is filled with data. The user can program the device to either stop any further recording (disable rollover) or overwrite the previously ...
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Temperature Alarm Logging For some applications it may be essential to not only record temperature over time and the temperature histogram, but also record when exactly the temperature has exceeded a predefined tolerance band and for how long the temperature ...
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MISSIONING The typical task of the DS1921L is recording the temperature of a temperature-sensitive object. Before the device can perform this function, it needs to be configured. This procedure is called missioning. First of all, DS1921L needs to have its ...
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ADDRESS REGISTERS AND TRANSFER STATUS Because of the serial data transfer, the DS1921L employs three address registers, called TA1, TA2 and E/S (Figure 9). Registers TA1 and TA2 must be loaded with the target address to which the data will ...
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MEMORY FUNCTION COMMANDS The Memory Function Flow Chart (Figure 10) describes the protocols necessary for accessing the memory and the special function registers of the DS1921L. An example on how to use these and other functions to set up the ...
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MEMORY FUNCTION FLOW CHART Figure 10-1 Master TX Memory or Control Fkt. Command Scratchpad DS1921 sets EMCLR = 0 Master TX TA1 (T7:T0), TA2 (T15:T8) DS1921 sets Scratch- pad Offset = (T4:T0) and Clears (PF, AA) Master TX Data Byte ...
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MEMORY FUNCTION FLOW CHART Figure 10-2 From Figure Part Scratchpad DS1921 sets EMCLR = 0 Master TX TA1 (T7:T0), TA2 (T15:T8) Master TX E/S Byte Authorization Code Match DS1921 Copies Scratchpad Data to Memory ...
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MEMORY FUNCTION FLOW CHART Figure 10-3 From Figure Part Decision made by DS1921 Decision made by Master To Figure Part A5H Read Mem. w/CRC Y DS1921 sets EMCLR = 0 Master TX TA1 (T7:T0), ...
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MEMORY FUNCTION FLOW CHART Figure 10-4 From Figure Part Memory EMCLR = 1? DS1921 clears Mission Time Stamp, Mission Samples Counter, Mission Start Delay, Sample Rate Register DS1921 clears Alarm Time Stamps and Durations DS1921 clears Histogram ...
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Copy Scratchpad [55h] This command is used to copy data from the scratchpad to the writable memory sections. After issuing the Copy Scratchpad command, the master must provide a 3-byte authorization pattern, which can be ob- tained by reading the ...
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DS1921L and CRC16s at page boundaries until a reset pulse is issued. The Read Memory with CRC command sequence can be ended at any point by issuing a reset pulse. Clear Memory [3Ch] The Clear Memory command is used ...
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Overdrive. The value of the pull-up resistor primarily depends on the network size and load conditions. For most applications the optimal value of the pull-up resistor will be approximately 2.2kW. The idle state for the 1-Wire bus is high. ...
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Read ROM [33h] This command allows the bus master to read the DS1921L's 8-bit family code, temperature range code, plus unique 36-bit serial number and 8-bit CRC. This command can only be used if there is a single DS1921L on ...
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ROM FUNCTIONS FLOW CHART Figure 12-1 From Memory Functions Flow Chart (Figure 10) 33H N Read ROM? Y DS1921 TX 1) Family Code Master TX Bit 0 1 Byte DS1921 TX 1) Temp. Range Master TX Bit 1 Pattern and ...
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ROM FUNCTIONS FLOW CHART Figure 12-2 To Figure Part From Figure Part From Figure Part To Figure Part N CCH 3CH Skip Overdrive ROM? Skip ROM? Y ...
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Overdrive Skip ROM [3Ch single-drop bus this command can save time by allowing the bus master to access the memory func- tions without providing the 64-bit ROM code. Unlike the normal Skip ROM command, the Overdrive Skip ROM ...
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INITIALIZATION PROCEDURE (RESET AND PRESENCE PULSES) Figure 13 MASTER TX RESET PULSE V PUP V IHMASTER ILMAX RESISTOR After the bus master has released the line it goes into receive mode (RX). ...
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READ/WRITE TIMING DIAGRAM Figure 14 Write-One Time Slot t V PUP V IHMASTER ILMAX RESISTOR Write-Zero Time Slot V PUP V IHMASTER ILMAX RESISTOR ...
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The master samples the data line at t time (d) on one side and t SPDMIN later than case of a read-one, the voltage on the 1-Wire line must be able to reach V SPDMIN t . ...
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CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL Figure STAGE STAGE STAGE STAGE STAGE Polynomial = ...
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MISSION EXAMPLE: PREPARE AND START A NEW MISSION Assumption: The previous mission has come to an end. To end an ongoing mission one may, for example, perform a sequence as in step 1 or write the MIP bit in the ...
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STEP 2 Set the EMCLR bit to 1, enable the RTC and then execute the Clear Memory command. This results in the following data to be written to the Status Register: Address: 20Eh Data: 40h With only a single DS1921L ...
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STEP 3 In this example, the rollover is disabled and the search condition is set for a high temperature only. The mission is to start with a delay of 90 (5Ah) minutes. This results in the following data to be ...
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STEP 4 In this example, the temperature alarms are set to -5°C for the low temperature threshold and 0°C for the high temperature threshold. The sample rate is once every 10 minutes, allowing the mission to last ...
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PHYSICAL SPECIFICATION Size Weight Humidity Altitude Safety ABSOLUTE MAXIMUM RATINGS* IO Voltage to GND IO sink current Temperature Range Junction Temperature Storage Temperature Range * This is a stress rating only and functional operation of the device at these or ...
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PARAMETER SYMBOL IO pin, 1-Wire Reset, Presence detect cycle Reset Low Time t RSTL Presence Detect High t PDH Time Presence Detect Low t PDL Time Presence Detect t MSP Sample Time IO pin, 1-Wire Write Write-0 Low Time t ...
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NOTES 1) System Requirement. 2) Maximum allowable pull-up resistance is a function of the number of 1-Wire devices in the system and 1-Wire recovery times. The specified value here applies to systems with only one device and with the minimum ...
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RTC Frequency Deviation vs Temperature -25 -50 -75 -100 -125 -150 -175 -200 -40 -30 -20 -10 Minimum Product Lifetime vs Temperature at Different Sample Rates Every Minute No Samples 11.00 10.00 9.00 8.00 7.00 6.00 5.00 ...
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Minimum Product Lifetime vs Sample Rate at Different Temperatures -40°C 50°C 11.00 10.00 9.00 8.00 7.00 6.00 5.00 4.00 3.00 2.00 1.00 0.00 1 -20 °C 15°C 40°C 55°C 60°C 70°C 10 100 Minutes between Samples 45°C ...