DS1991L-F5 Maxim Integrated Products, DS1991L-F5 Datasheet
DS1991L-F5
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DS1991L-F5 Summary of contents
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... Meets UL#913 (4th Edit.); Intrinsically Safe Apparatus, Approved under Entity Concept for use in Class I, Division 1, Group and D Locations F5 MICROCAN 5.89 0.51 IO GND All dimension\s shown in millimeters ORDERING INFORMATION DS1991L-F5 ® ® EXAMPLES OF ACCESSORIES DS9096P DS9101 DS9093RA DS9093F DS9092 DS1991 MultiKey iButton ® ...
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DESCRIPTION The DS1991 MultiKey iButton is a rugged read/write data carrier that acts as three separate electronic keys, offering 1,152 bits of secure, nonvolatile memory. Each key is 384 bits long with distinct 64-bit password and public ID fields ...
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For the first use, since the passwords actually stored in the device are unknown, the DS1991 needs to be initialized. This is done by directly writing (i. e., not through the scratchpad) the new identifier and password for the selected ...
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DS1991 COMMAND STRUCTURE Figure 4 st Command 1 write 96H scratchpad read 69H scratchpad copy 3CH scratchpad read 66H SubKey write 99H SubKey write 5AH password SCRATCHPAD COMMANDS The 64-byte read/write scratchpad of the DS1991 is not password-protected. Its normal ...
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Write Password [5AH] The Write Password command is used to enter the ID and password of the selected subkey. This command will erase all of the data stored in the secure area as well as overwriting the ID and password ...
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MEMORY FUNCTIONS FLOW CHART (cont’d) Figure DS1991 ...
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BLOCK SELECTOR CODES OF THE DS1991 Figure 6 Block Nr. Address Range 3FH 0 identifier 1 password 2 10H to 17H 3 18H to 1FH 4 20H to 27H 5 28H to 2FH 6 30H ...
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The bus master requires a pullup resistor at the master end of the bus, with the bus master circuit equivalent to the one shown in Figures 8a and 8b. The value of the pullup resistor should be approximately 5 kΩ ...
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EQUIVALENT CIRCUIT Figure 7 BUS MASTER CIRCUIT Figure DS1991 ...
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TRANSACTION SEQUENCE The protocol for accessing the DS1991 via the 1-Wire port is as follows: • Initialization • ROM Function Command • Memory or SHA Function Command • Transaction/Data INITIALIZATION All transactions on the 1-Wire bus begin with an initialization ...
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SIGNALING The DS1991 requires strict protocols to ensure data integrity. The protocol consists of four types of signaling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write 0, Write 1 and Read Data. All these signals ...
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INITIALIZATION PROCEDURE “RESET AND PRESENCE PULSES” Figure 10 RESISTOR MASTER DS1991 ∗ In order not to mask interrupt signaling by other devices on the 1-Wire bus less than 960 μs. READ/WRITE TIME SLOTS The definitions of write and ...
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READ/WRITE TIMING DIAGRAM (cont’d) Figure 11 Write-Zero Time Slot Read-Data Time Slot RESISTOR MASTER DS1991 60 μs < t < 120 μs < t LOW0 SLOT 1 μs < t < ∞ REC 60 μs ≤ t < 120 μs ...
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PHYSICAL SPECIFICATIONS Size Weight Expected Service Life Safety ABSOLUTE MAXIMUM RATINGS* Voltage on any Pin Relative to Ground Operating Temperature Storage Temperature ∗ This is a stress rating only and functional operation of the device at these or any other ...
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NOTES: 1. All voltages are referenced to ground external pullup voltage to system supply. PUP 3. Input pulldown resistance to ground additional reset or communication sequence cannot begin until the reset high time has expired. ...