DS1921H Maxim, DS1921H Datasheet
DS1921H
Related parts for DS1921H
DS1921H 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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... The DS1921H has a fixed range of +15°C to +46°C. The DS1921Z has a fixed range of -5°C to +26°C. The high resolution makes the DS1921H and DS1921Z suitable for scientific research and development. The read/write NV memory can store information such as shipping manifests, dates of manufacture, or other relevant data written as ASCII or encrypted files ...
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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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... Memory/Control Function Commands 64-BIT 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 ...
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... X MEMORY The memory map of the DS1921H/Z 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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... 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 Minutes Alarm 0209h MH 12/24 020Ah MD 0 020Bh 020Ch 020Dh Number of Minutes Between Temperature Conversions ...
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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 DS1921H/Z 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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... T[7… ϑ (°C) -116 (DS1921H) T[7… ϑ (° (DS1921Z) A value of 23°C, for example, thus translates into 68 decimal or 44h for the DS1921H, and 228 decimal or E4h for the DS1921Z. This corresponds to the binary patterns 0100 0100 and 1110 0100 respectively, which could be written to a Temperature Alarm Register (address 020Bh and 020Ch, respectively). ...
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... CONTROL REGISTER The DS1921H/Z is set up for its operation by writing appropriate data to its special function registers that are located in the register page. Several functions that are controlled by a single bit only are combined into a single byte called Control Register (address 20Eh). This register can be read and written. If the device is programmed for a mission, writing to the Control Register will end the mission and change the register contents ...
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... The maximum delay is 65535 minutes, equivalent to 45 days, 12 hours, and 15 minutes. For a typical mission, the Mission Start Delay mission is too long for a single DS1921H/Z to store all temperature readings at the selected sample rate, one can use several devices, staggering the Mission Start Delay to record the full period ...
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... This counter is reset through the Clear Memory command this bit reads 1 the DS1921H/Z 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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... There are two alternatives to the way the DS1921H/Z will behave after the 2048 bytes of datalog memory is filled with data. With rollover disabled (RO = 0), the device will fill the datalog memory with the first 2048 mission samples ...
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... The DS1921H/Z 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, DS1921H/Z 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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... The sample rate may be any value from 1 to 255, coded as an unsigned 8-bit binary number. As soon as the sample rate is written, the DS1921H/Z will set the MIP flag and clear the MEMCLR flag. After as many minutes as specified by the Mission Start Delay are over, the device will wait for the next minute boundary, then wake up, copy the current time and date to the Mission Time Stamp Register, and make the first temperature conversion of the mission ...
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... Only) WRITING WITH VERIFICATION To write data to the DS1921H/Z, the scratchpad has to be used as intermediate storage. First, the master issues the Write Scratchpad command to specify the desired target address, followed by the data to be written to the scratchpad. In the next step, the master sends the Read Scratchpad command to read the scratchpad and to verify data integrity ...
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... The ending offset/data status byte is unaffected. The hardware of the DS1921H/Z provides a means to accomplish error-free writing to the memory sec- tion. To safeguard data in the 1-Wire environment when reading and to simultaneously speed up data transfers recommended to packetize data into data packets of the size of one memory page each ...
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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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... The command works essentially the same way as the simple Read Memory, except for the 16-bit CRC that the DS1921H/Z generates and transmits following the last data byte of a memory page. ...
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... MEMCLR bit will be cleared to indicate that the device mission. Next the Mission Start Delay counter will start decrementing every minute until it is down to 0. Now the DS1921H/Z will wait until the next minute boundary and start the logging process, which as its first action copies the applicable RTC registers to the Mission Time Stamp ...
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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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... All transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by the slave(s).The presence pulse lets the bus master know that the DS1921H the bus and is ready to operate. For more details, see the 1-Wire Signaling section. ...
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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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... The initialization sequence required to begin any communication with the DS1921H/Z is shown in Figure 14. A Reset Pulse followed by a Presence Pulse indicates the DS1921H/Z is ready to receive data, given the correct ROM and memory function command. If the bus master uses slew-rate control on the falling edge, it must pull down the line for t longer will exit the Overdrive mode returning the device to standard speed ...
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... Wire devices. Read/Write Time Slots Data communication with the DS1921H/Z 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 15. ...
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... DS1921H/Z will start pulling the data line low; its internal timing generator determines when this pull- down ends and the voltage starts rising again. When responding with a 1, the DS1921H/Z will not hold the data line low at all, and the voltage starts rising as soon as t The sum δ ...
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... With the Write Scratchpad command the CRC is generated by first clearing the CRC generator and then shifting in the command code, the target addresses TA1 and TA2 and all the data bytes. The DS1921H/Z will transmit this CRC only if the data bytes written to the scratchpad include scratchpad ending offset 11111b ...
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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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... 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 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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... Clear Memory command is issued. Wait 500 µs after issuing the Clear Memory command before proceeding to Step 3. This results in the following data to be written to the Status Register: Address: 20Eh Data: 40h With only a single DS1921H/Z 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 DS1921H/Z connected to the bus master, the communication of step follows: MASTER MODE ...
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... 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 function registers: Address: 20Bh Data: 2Ch With only a single DS1921H/Z connected to the bus master, the communication of step follows: MASTER MODE ...
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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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... Standard Speed 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 ...
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... W1LMAX DS1921H/Z Values Standard Speed Overdrive Speed min max min 1) 1) 65µs (undef.) 8µs 540µs 640µs 48µs 15µs 60µs 1.1µs 60µs 270µ ...
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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 bullet “Water resistant or waterproof if placed inside DS9107 iButton capsule (Exceeds Water Resistant 3 ATM requirements)”. Add text to Application section: Note that the initial sealing level of DS1921H/Z achieves IP56. Aging and use conditions can degrade the 120407 integrity of the seal over time, so for applications with significant exposure to liquids, sprays, or other similar environments recommended to place the Thermochron in the DS9107 iButton capsule ...