DS1921L-F5X Dallas Semiconducotr, DS1921L-F5X Datasheet
DS1921L-F5X
Related parts for DS1921L-F5X
DS1921L-F5X Summary of contents
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... Data can be accessed while affixed to object § Button shape is self-aligning with cup-shaped probes 1-Wire, Microcan, and iButton are registered trademarks of Dallas Semiconductor *See ELECTRICAL CHARACTERISTICS table for details. DS1921L-F5X Thermochron iButton § Durable stainless steel case engraved with registration number withstands harsh envi- ronments § ...
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... APPLICATION The DS1921L Thermochron iButton is an ideal device to monitor the temperature of any object it is attached to or shipped with, such as perishable goods or containers of temperature sensitive chemicals. Using TMEX, the read/write NV memory can store an electronic copy of shipping information, date of manufacture and other important data written as clear as well as encrypted files ...
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... ROM may still be read normally. 64-BIT LASERED ROM Each DS1921L contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code. 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 ...
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... Temperature 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 ...
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... X MEMORY The memory map of the DS1921L is shown in Figure 5. The 4096-bit general-purpose SRAM make up pages 0 through 15. The timekeeping, control, and counter registers fill page 16, called Register Page (see Figure 6). Pages are assigned to storing the alarm time stamps and durations. The temperature histogram bins begin at page 64 and use up to four pages ...
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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; R** 0214h R/W; R/W 0215h to 0219h 021Ah to 021Ch 021Dh to 021Fh *The first entry in column ACCESS TYPE is valid between missions. The second entry shows the applicable access type while a mission is in progress ...
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... In the 12-hour mode, bit 5 is the AM/PM bit with logic 1 being PM. In the 24-hour mode, bit 5 is the 20- hour bit ( hours). To distinguish between the days of the week the DS1921L includes a counter with a range from The assignment of counter value to the day of week is arbitrary. Typically, the number 1 is assigned to a Sunday (U ...
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... FAh (if too high). Since out-of-range results are accumulated in histogram bins 0 and 62 (see section Temperature Logging and Histogram) the data in these bins is of limited value. For this reason the specified temperature range of the DS1921L is considered to begin at code 04h and end at code F7h, which corresponds to histogram bins 1 to 61. ...
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... For a typical mission, the Mission Start Delay mission is too long for a single DS1921L to store all temperature readings at the selected sample rate, one can use several devices and set the Mission Start Delay for the second device to start recording as soon as the memory of the first device is full ...
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... EM bit is also 0. The memory has to be cleared in order for a mission to start this bit reads 1 the DS1921L has been set up for a mission and this mission is still in progress. A mission is started if the EM bit of the Control Register (address 20Eh and a non-zero value is written to the Sample Rate Register, address 20Dh ...
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... Temperature Logging and Histogram Once setup for a mission, the DS1921L logs the temperature measurements simultaneously byte after byte in the datalog memory as well as in histogram form in the histogram memory. The datalog memory is able to store 2048 temperature values measured at equidistant time points. The first temperature value of a mission is written to address location 1000h of the datalog memory, the second value to address location 1001h and so on ...
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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 recorded data (enable rollover), one byte at a time, starting again at address ...
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... The DS1921L can log high and low durations. The tolerance band is specified by means of the Temperature Alarm Threshold Registers, addresses 20Bh and 20Ch in the register page ...
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... This procedure is called missioning. First of all, DS1921L needs to have its RTC set to valid time and date. This reference time may be UTC (also called GMT, Greenwich Mean Time) or any other time standard that was chosen for the application. ...
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... After the master has verified the data, it has to send the Copy Scratchpad command. This command must be followed exactly by the data of the three address registers TA1, TA2 and E/S as the master has read them verifying the scratchpad. As soon as the DS1921L has received these bytes, it will copy the data to the requested location beginning at the target address. ...
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... 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 DS1921L for a mission is included at the end of this document, preceding the Electrical Characteristics section. The communication between master and DS1921L takes place either at regular speed (default Overdrive Speed ( ...
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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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... The command works essentially the same way as the simple Read Memory, except for the 16-bit CRC that the DS1921L generates and transmits following the last data byte of a memory page. ...
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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 to clear the Sample Rate, Mission Start Delay, Mission Time Stamp, and Mission Samples Counter in the register page and the Temperature Alarm Memory and the Temperature Histogram Memory ...
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... The presence pulse lets the bus master know that the DS1921L is on the bus and is ready to operate. For more details, see the 1-Wire Signaling section. ROM FUNCTION COMMANDS Once the bus master has detected a presence, it can issue one of the seven ROM function commands ...
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... CRC. This command can only be used if there is a single DS1921L on the bus. If more than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the same time (open drain will produce a wired-AND result). The resultant family code and temperature range code plus 36-bit serial number will result in a mismatch of the CRC ...
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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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... The initialization sequence required to begin any communication with the DS1921L is shown in Figure 13. A Reset Pulse followed by a Presence Pulse indicates the DS1921L is ready to receive data, given the correct ROM and memory function command mixed population network, the reset low time t needs to be long enough for the slowest 1-Wire slave device to recognize reset pulse. With the DS1921L this duration is 480µ ...
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... Wire devices. Read/Write Time Slots Data communication with the DS1921L takes place in time slots that carry a single bit each. Write time slots transport data from bus master to slave. Read time-slots transfer data from slave to master. The definitions of the write and read time slots are illustrated in Figure 14. ...
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... As the voltage on the 1-Wire line falls below the threshold V DS1921L starts its internal time base. The master pull-down time (t to cover the setup time t , after which the DS1921L delivers a bit to its 1-Wire port. When transmitting the DS1921L will hold the data line low for t data line low at all ...
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... ROM. The bus master can compute a CRC value from the first 56 bits of the 64-bit ROM and compare it to the value stored within the DS1921L to determine if the ROM data has been received error-free. The equivalent polynomial function of this CRC ...
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CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL Figure STAGE STAGE STAGE STAGE STAGE Polynomial = ...
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... 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 Status Register to 0. The preparation of a DS1921L for a mission including the start of the mission requires up to four steps: Step 1: set the RTC (if it needs to be adjusted) ...
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... 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 connected to the bus master, the communication of step follows: MASTER MODE ...
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... Writing through address locations 20Fh to 211h is faster than accessing the Mission Start Delay Register in a separate cycle. The write attempt has no effect on the contents of these registers. With only a single DS1921L connected to the bus master, the communication of step follows: MASTER MODE ...
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... The sample rate is once every 10 minutes, allowing the mission to last days. This results in the following data to be written to the special function registers: Address: 20Bh Data: 46h With only a single DS1921L connected to the bus master, the communication of step follows: MASTER MODE ...
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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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... Standard Speed Overdrive Speed Standard Speed Overdrive Speed Standard Speed Overdrive Speed Standard Speed Overdrive Speed Standard Speed Overdrive Speed -5°C to +46°C F DS1921L-F50 DS1921L-F51 DS1921L-F52 DS1921L-F53 MIN TYP MAX UNITS NOTES 480 640 µs 540 640 µs 1 ...
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... DS1921L Values Standard Speed Overdrive Speed min max min 65µs (undef.) 8µs 540µs 640µs 48µs 15µs 60µs 1.1µ ...
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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 ...