DS1921Z Maxim, DS1921Z Datasheet
DS1921Z
Related parts for DS1921Z
DS1921Z Summary of contents
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... ORDERING INFORMATION PART DS1921H-F5# DS1921Z-F5# #Denotes a RoHS-compliant device that may include lead(Pb) that is exempt under the RoHS requirements. EXAMPLES OF ACCESSORIES DS9096P DS9101 DS9093RA DS9093A DS9092 DS1921H/DS1921Z 5.89 0.51 3B2000FBC52B 1-Wire Thermochron ® GND All dimensions are shown in millimeters. ...
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... APPLICATION The DS1921Z is an ideal device to monitor the temperature of any object it is attached to or shipped with, such as fresh produce, medical drugs and supplies also ideal for use in refrigerators. The DS1921H is intended for monitoring the body temperature of humans and animals and for monitoring temperature critical processes such as curing, powder coating, and painting ...
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... The next 36 bits are a unique serial number. The next 12 bits, called temperature range code, allow distinguishing the DS1921H and DS1921Z from each other and from other DS1921 versions. 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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... LASERED ROM Figure 3 MSB 8-Bit 12-Bit Temperature CRC Code Range Code MSB LSB MSB DEVICE TEMP. RANGE (°C) 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 DS1921H/Z is shown in Figure 5. The 4096-bit general-purpose SRAM make up pages 0 ...
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DS1921H/Z REGISTER PAGE MAP Figure 6 ADDR b7 b6 0200h 0 10 Seconds 0201h 0 10 Minutes 0202h 0 12/24 0203h 0 0 0204h 0 0 0205h CENT 0 0206h 10 Years 0207h MS 10 Seconds Alarm 0208h MM 10 ...
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RTC and RTC Alarm Register Bitmap ADDR b7 b6 0200h 0 10 Seconds 0201h 0 10 Minutes 0202h 0 12/24 0203h 0 0 0204h 0 0 0205h CENT 0 0206h 10 Years 0207h MS 10 Seconds Alarm 0208h MM 10 ...
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... FFh (if too high). Since out-of-range results are accumulated in histogram bins 0 and 63 the data in these bins is of limited value (see the Temperature Logging and Histogram section). For this reason the specified temperature range of the DS1921H and DS1921Z is considered to begin at code 04h and end at code FBh, which corresponds to histogram bins 1 to 62. ...
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SAMPLE RATE The content of the Sample Rate Register (address 020Dh) determines how many minutes the temperature conversions are apart from each other during a mission. The sample rate may be any value from 1 to 255, coded as an ...
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... The content of the Mission Start Delay Counter determines how many minutes the device will wait before starting the logging process. The mission start delay value is stored as unsigned 16-bit integer number at addresses 212h (low byte) and 213h (high byte). The maximum delay is 65535 minutes, equivalent to 45 days, 12 hours, and 15 minutes. ...
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... The SIP bit will change from approximately 250ms before the actual temperature conversion begins allowing the circuitry of the chip to wake-up. A temperature conversion including a wake-up phase takes maximum 875ms. During this time read accesses to the memory pages 17 and higher are permissible but may reveal invalid data. ...
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... The Device Samples Counter indicates how many temperature measurements have taken place since the device was assembled at the factory. The value is stored as an unsigned 24-bit integer number. The maximum number that can be represented in this format is 16777215, which is higher than the expected lifetime of the DS1921H/Z iButton. This counter cannot be reset under software control. ...
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... Commands). The device also generates a time stamp of when the alarm occurred and begins recording the duration of the alarming temperature. Time stamps and durations where the temperature leaves the tolerance band are stored in the address range 0220h to 027Fh, as shown in Figure 8. This allocation allows recording 24 individual alarm events DS1921Z TEMP. HISTOGRAM BIN EQUIV. IN °C NUMBER -5 ...
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The date and time of each of these periods can be determined from the Mission Time Stamp and the time distance between each temperature reading. ALARM TIME STAMPS ...
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The state of the Search Condition bits in the Control Register does not affect the mission. If multiple devices are connected to form a 1-Wire net, the setting of the search condition will enable devices to participate in the conditional ...
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If the target address for a Write command is 13Ch, for example, then the scratchpad will store incoming data beginning at the byte offset 1Ch and will be full after only 4 bytes. The corresponding ending offset in ...
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This CRC is generated using the CRC16 polynomial by first clearing the CRC generator and then shifting in the command code (0Fh) of the Write Scratchpad command, the Target Addresses TA1 and TA2 as supplied ...
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MEMORY/CONTROL 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/CONTROL 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/CONTROL 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/CONTROL FUNCTION FLOW CHART Figure 10-4 From Figure 10 3CH rd 3 Part Clear Memory Y EMCLR = 1? Y DS1921 clears Mission Time Stamp, Mission Samples Counter, Mission Start Delay, Sample Rate Register DS1921 clears Alarm Time Stamps and ...
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... If a mission is not in progress (MIP = 0) the Convert Temperature command can be issued to measure the current temperature of the device. The result of the temperature conversion will be found at memory address 211h in the register page. This command takes maximum 360ms to complete. During this time the device remains fully accessible for memory/control and ROM function commands. ...
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Mission Start and Logging Process The DS1921H/Z does not use a special command to start a mission. Instead, a mission is started by writing a non-zero value to the Sample Rate Register using the Copy Scratchpad command. As shown in ...
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... Note that the DS1921H/Z does not quite meet the full 16µs maximum low time of the normal 1-Wire bus Overdrive timing. With the DS1921H/Z the bus must be left low for no longer than 15µ ...
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HARDWARE CONFIGURATION Figure 12 BUS MASTER RX TX Open Drain Port Pin TRANSACTION SEQUENCE The protocol for accessing the DS1921H/Z via the 1-Wire port is as follows: Initialization ROM Function Command Memory/Control Function Command Transaction/Data INITIALIZATION ...
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Search ROM [F0h] When a system is initially brought up, the bus master might not know the number of devices on the 1- Wire bus or their registration numbers. By taking advantage of the wired-AND property of the bus, the ...
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ROM FUNCTIONS FLOW CHART Figure 13-1 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 Code and ...
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ROM FUNCTIONS FLOW CHART Figure 13-2 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/control functions without providing the 64-bit ROM code. Unlike the normal Skip ROM command, the Overdrive Skip ROM sets ...
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INITIALIZATION PROCEDURE (RESET AND PRESENCE PULSES) Figure 14 After the bus master has released the line it goes into receive mode (RX). Now, the 1-Wire bus is pulled to V via the pull-up resistor or, in case of a DS2480B ...
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READ/WRITE TIMING DIAGRAM Figure 15 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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CRC GENERATION With the DS1921H/Z there are two different types of Cyclic Redundancy Checks (CRCs). One CRC is an 8-bit type and is stored in the most significant byte of the 64-bit ROM. The bus master can compute a CRC ...
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CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL Figure STAGE STAGE STAGE STAGE STAGE Command-Specific 1-Wire Communication Protocol — Legend Symbol Description ...
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Command-Specific 1-Wire Communication Protocol — Color Codes Master to slave Slave to master Write Scratchpad, reaching the end of the Scratchpad RST PD Select WS Write Scratchpad, not reaching the end of the Scratchpad RST PD Select WS Read Scratchpad ...
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Read Memory with CRC (invalid address) RST PD Select RMC The "32 bytes" are all 00h. Clear Memory RST PD Select CM To verify success, read the Status Register at address 0214h. If MEMCLR is 1, the command was executed ...
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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 write the MIP bit in the Status Register to 0. The preparation of a DS1921H/Z for a mission ...
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STEP 2 Set the EMCLR bit to 1, enable the RTC and then execute the Clear Memory command. The RTC oscillator must be stable before the Clear Memory command is issued. Wait 500 µs after issuing the Clear Memory command ...
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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 (005Ah) minutes and the alarm flags TLF, THF, and TAF ...
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... In this example, the temperature alarms are set to 0°C for the low temperature threshold and 10°C for the high temperature threshold, assuming DS1921Z device. 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 ...
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... Weight ABSOLUTE MAXIMUM RATINGS* IO Voltage to GND IO Sink Current Temperature Range DS1921H, DS1921Z Storage Temperature Range * This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. ...
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... Overdrive Speed Standard Speed Overdrive Speed Standard Speed RL Overdrive Speed Standard Speed Overdrive Speed -5°C to +46°C F DS1921H TC DS1921Z has been applied the parasite capacitor will not affect normal PUP and V maximum specifications are valid PUP ILMAX MIN ...
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... Figure 15 represents the time required for the pull-up circuitry to pull the voltage from The actual maximum duration for the master to pull the line low ε and ε, respectively. W0LMAX F 12) δ in Figure 15 represents the time required for the pull-up circuitry to pull the voltage from V to the input high threshold of the bus master ...
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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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... PACKAGE INFORMATION For the latest package outline information and land patterns (footprints www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. ...
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... Added the Package Information section and completed the Revision History. Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. ...