DS2703 Dallas Semiconductor, DS2703 Datasheet
DS2703
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DS2703 Summary of contents
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... GENERAL DESCRIPTION The DS2703 provides a robust cryptographic solution to ensure the authenticity of Li-Ion battery packs for cell phone, PDA, and portable computing devices. The DS2703 employs the Secure Hash Algorithm (SHA-1) specified in the publication 180-1 and 180-2, and ISO/IEC 10118-3. ...
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ABSOLUTE MAXIMUM RATINGS Voltage Range on DQ, THM Pins Relative to Ground Voltage Range on VB Pin Relative to Ground Operating Temperature Range Storage Temperature Range Soldering Temperature Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage ...
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... Time from msb of Activate Thermistor command until THM pin is driven low internally. Note 12: Time from msb of Compute Next Secret or Compute MAC command. Note 13: Time after initial power up before the DS2703 will respond to communication. T Worst case 100ms delay based on maximum thermistor value of 500kΩ. SYMBOL CONDITIONS ...
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... Data Input/Output. 1-Wire data line. Open-drain output driver. Connect this pin to the 3 DQ DATA terminal of the battery pack. This pin has a weak internal pulldown (1µA Typical). Hold-up Supply Bypass Input. Internal power supply to the DS2703 while DQ is low Connect a 0.22µF capacitor from Connect ...
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... DETAILED DESCRIPTION The DS2703 is comprised of a SHA-1 Authentication function and thermistor mux control that are accessed via a 1- Wire interface. The high voltage (HV) detection circuit routes the externally supplied programming voltage to the EEPROM array and enables the internal regulator to isolate portions of the chip from the programming voltage. The 1-Wire interface controls access by a host system to the 64-bit Net Address (ROM ID) and SHA-1 Authentication ...
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Table 1. Variable Initiation [31:0] A 67h B EFh C 98h D 10h E C3h The 160-bit MAC is computed per FIPS 180, including the addition of constants H0-H4. Adding H0-H4 is necessary only to maintain compliance with FIPS 180. ...
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... This command is structured the same as the Compute MAC without ROM ID, except that the ROM ID is loaded to the message block. Including the ROM ID unique to each DS2703 in the MAC computation allows the use of a unique secret in each token and a master secret in the host device. See application note “White Paper 4”, available at http://www ...
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Table 3. Authentication Function Commands COMMAND Write Challenge Compute MAC without ROM ID and return MAC Compute MAC with ROM ID and return MAC SECRET MANAGEMENT FUNCTION COMMANDS LOAD SECRET [5Ah]. This command writes the 64-bit secret to the provided ...
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... IC to power cycle back to standard mode of operation. While in thermistor measurement mode, communication to the DS2703 is not possible. After measuring the thermistor, the host must wait until the VB capacitor is depleted. Figure 2 shows the typical and worst case transition times over the full operating range when using .22µ ...
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... Address is synonymous with the ROM ID or ROM Code terms used in earlier Dallas 1-Wire product documentation. The first eight bits of the Net Address are the 1-Wire family code, (34h) for the DS2703. The next 48 bits are a unique serial number. The last eight bits are a cyclic redundancy check (CRC) of the first 56 bits (see Figure 3.). ...
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... HARDWARE CONFIGURATION The DS2703 uses an open-drain output driver as part of the bidirectional interface circuitry shown in Figure bidirectional pin is not available on the bus master, separate output and input pins can be connected together. For normal communication the 1-Wire bus must have a pullup resistor at the bus-master end of the bus. For short line lengths and/or V ≥ ...
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... This command can be used with one or more slave devices on the bus. Skip Net Address [CCh]. This command saves time when there is only one DS2703 on the bus by allowing the bus master to issue a function command without specifying the address of the slave. If more than one slave device is present on the bus, a subsequent function command can cause a data collision when all slaves transmit data at the same time ...
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... F0h MATCH SEARCH YES YES DS2703 Tx BIT 0 MASTER Tx BIT 0 DS2703 Tx BIT 0 MASTER Tx BIT BIT 0 BIT 0 MATCH? MATCH? YES DS2703 Tx BIT 1 MASTER Tx BIT 1 DS2703 Tx BIT 1 MASTER Tx BIT BIT 1 BIT 1 MATCH? MATCH? YES YES DS2703 Tx BIT 63 MASTER Tx BIT 63 DS2703 Tx BIT 63 MASTER Tx BIT 63 ...
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... A read-time slot is initiated when the bus master pulls the 1-Wire bus line from a logic-high level to a logic-low level. The bus master must keep the bus line low for at least 1ms and then release it to allow the DS2703 to present valid data. The bus master can then sample the data t time slot, the DS2703 releases the bus line and allows pulled high by the external pullup resistor ...
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Figure 8. 1-Wire Write and Read Time Slots WRITE 0 SLOT t SLOT t LOW0 V PULLUP GND Device Sample Window MIN TYP MODE Standard 15ms 15ms Overdrive 2ms 1ms t SLOT V t PULLUP RDV GND Master Sample Window ...
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... Generates new unique secret. Requires programming pulse. Sets lock bit to prevent changes to the Secret. Requires programming pulse. Sets 1-Wire interface timings to OVERDRIVE. Requires programming pulse. Sets 1-Wire interface timings to STANDARD. Requires programming pulse. Resets DS2703 (Software POR). ISSUE 00h BEFORE READ X ...
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LOW-IMPEDANCE DQ DURING COMPUTATION The SHA-1 computation requires more current than the DQ pullup resistor used during normal communication can supply. During the computation, the DQ source impedance must be reduced to maintain power to the device under the higher ...
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PROGRAMMING PULSE A typical programming waveform is shown in Figure 10. The user issues a 1-Wire reset followed by a Skip ROMID command, Match ROMID plus the ROMID, Search or Read Net, the Load Secret command and then the two ...
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COMPUTATION AND PROGRAMMING The Compute Next Secret operation waveform is shown in Figure 11. The user issues a 1-Wire reset followed by a Skip ROMID command, Match ROMID plus the ROMID, Search or Read Net, followed by the Compute Next ...
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... THM pin low. Immediately following the Activate Thermistor command, the host system should enable the weak pullup to VCC and then measure the thermistor by sampling the voltage level of the 1-Wire bus within time t . The DS2703 automatically reverts back to communication mode after t MIN Figure 12. ...