DS2436 Dallas Semiconducotr, DS2436 Datasheet
DS2436
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DS2436 Summary of contents
Page 1
... A cycle counter assists to determine the remaining cycle life of the battery. Finally, the DS2436 measures battery voltage and sends that measured value to a host CPU for use in end-of-charge or end-of-discharge determination or basic fuel gauge operation. Information is sent to/from the DS2436 over a 1-Wire interface, so that battery packs need only have three output connectors: power, ground, and the 1-Wire interface ...
Page 2
... DS2436, allowing this information to be permanently stored in the battery pack. PARASITE POWER The ID ROM registers and memory of the DS2436 can be read even when the battery is completely discharged by using parasite-powered operation. When parasite powered, the DS2436 “steals” power from the DQ line whenever it is high. DQ will provide sufficient power for read operations as long as specified timing and voltage requirements are met (see the section titled “ ...
Page 3
... DS2436 BLOCK DIAGRAM Figure 1 TEMPERATURE MEASURING CIRCUITRY A/D CONVERTER V DD 64-BIT ROM ID AND DQ 1-WIRE PORT GDD CONTROL LOGIC AND MEMORY FUNCTION CONTROL 256-BIT SCRATCHPAD 64-BIT SCRATCHPAD DS2436 TEMPERATURE REGISTER STATUS REGISTER VOLTAGE REGISTER CYCLE COUNTER MANUFACTURER ID 256-BIT NONVOLATILE RAM 64-BIT RAM ...
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... DS2436 MEMORY PARTITIONING Figure 2 LSB MSB LSB MSB LSB MSB LSB MSB LSB MSB DS2436 ...
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... DS2436 MEMORY MAP Figure 3 PAGE 1 USER BYTE USER BYTE USER BYTE USER BYTE SP1 USER BYTE OR USER BYTE NV1 USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE USER BYTE ...
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... DS2436 MEMORY MAP (cont’d) Figure 3 PAGE 2 USER BYTE USER BYTE USER BYTE USER BYTE SP2 USER BYTE OR USER BYTE NV2 USER BYTE USER BYTE RESERVED ADDRESS SPACE BYTE ADDRESS 0 20h 1 21h 2 22h 3 23h 4 24h 5 25h 6 26h 7 27h 8 28h 31 3Fh ...
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... DS2436 MEMORY MAP (cont’d) Figure 3 PAGE 3 USER BYTE USER BYTE USER BYTE USER BYTE SP3 USER BYTE OR USER BYTE SRAM USER BYTE USER BYTE RESERVED ADDRESS SPACE BYTE ADDRESS 0 40h 1 41h 2 42h 3 43h 4 44h 5 45h 6 46h 7 47h 31 5Fh DS2436 ...
Page 8
... DS2436 MEMORY MAP (cont’d) Figure 3 PAGE 4 TEMPERATURE LSB TEMPERATURE MSB STATUS LSB REGISTERS STATUS LSB RESERVED ADDRESS SPACE VOLTAGE LSB VOLTAGE MSB RESERVED ADDRESS SPACE BYTE ADDRESS 0 60h 1 61h 2 62h 3 63h 4 64h 5 65h 6 66h 7 67h 8 68h 9 69h 10 6Ah 11 6Bh 12 6Ch ...
Page 9
... DS2436 MEMORY MAP (cont’d) Figure 3 PAGE 5 MFG ID LSB MFG ID MSB CYCLE CTR LSB REGISTERS CYCLE CTR LSB RESERVED ADDRESS SPACE BYTE ADDRESS 0 80h 1 81h 2 82h 3 83h 31 9Fh DS2436 ...
Page 10
... DS2436 is lost, this data may also be lost without serious repercussions. Data which must remain even if power to the DS2436 is lost should be placed in either Page 1 or Page 2. Prefer this section of memory to store fuel gauge and self discharge information. If the battery dies and this information is lost, no serious consequences will result since the user can easily determine that the battery is dead ...
Page 11
... The DS2436 can measure temperature over the range of -40°C to +85°C in 0.03125°C increments. For Fahrenheit usage, a lookup table or conversion factor must be used. Note that temperature is represented in the DS2436 in terms of a 0.03125°C LSB, yielding the following 13-bit format: ...
Page 12
... DS2436 receives the command protocol (Convert V) [B4h]. The result of this measurement is placed in the 2-byte Voltage Register (see Memory Map). The range for the DS2436 ADC 10V; this range is suitable for NiCd or NiMH battery packs up to six cells, and for lithium ion battery packs of two cells ...
Page 13
... The Cycle Counter does not roll over when it reaches its maximum value (FFFFh). MEMORY FUNCTION COMMANDS 64-BIT LASERED ROM Each DS2436 contains a unique ROM code that is 64 bits long. The first 8 bits are a 1-Wire family code (DS2436 code is 1Bh). The next 48 bits are a unique serial number. The last 8 bits are a Cyclic Redundancy Check (CRC) of the first 56 bits ...
Page 14
... There is no circuitry inside the DS2436 that prevents a command sequence from proceeding if the CRC stored in or calculated by the DS2436 does not match the value generated by the bus master. Proper use of the CRC can result in a communication channel with a very high level of integrity. ...
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... ROM FUNCTIONS FLOW CHART Figure DS2436 ...
Page 16
... The presence pulse lets the bus master know that the DS2436 is on the bus and is ready to operate. For more details, see the “1-Wire Signaling” section. ...
Page 17
... This command allows the bus master to read the DS2436’s 8-bit family code, unique 48-bit serial number, and 8-bit CRC. This command can only be used if there is a single DS2436 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) ...
Page 18
... This completes the first pass and uniquely identifies one part on the 1-Wire bus. 10. The bus master starts a new ROM search sequence by repeating steps 1 through 7. 11. The bus master writes a 1-bit. This deselects ROM4, leaving only ROM1 still coupled DS2436 ...
Page 19
... If reading occurs through the end of a page, the Bus Master may issue eight additional read time slots and the DS2436 will respond with an 8-bit CRC of all data bytes read from the initial starting byte through the last byte of the page. After the CRC is received by the Bus Master, any subsequent read time slots will appear as logical 1s until a reset pulse is issued ...
Page 20
... This command copies the entire contents (8 bytes) of SRAM to its corresponding scratchpad RAM (SP3). This command does not use a start address; the entire contents of SRAM will be copied to SP3. The SRAM of the DS2436 cannot be read directly by the bus master; however, the SRAM may be copied to the scratchpad RAM. ...
Page 21
... PAGE 4 AND 5 COMMANDS Convert T [D2h] This command instructs the DS2436 to initiate a temperature conversion cycle. This sets the TB flag. When the temperature conversion is done, the TB flag is reset and the temperature value is placed in the Temperature Register. While a temperature conversion is taking place, all other memory functions are still available for use, but the Temperature Register should not be read until the TB flag has been reset ...
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... DS2436 COMMAND SET Table 3 INSTRUCTION DESCRIPTION Reads bytes from Read Scratchpad DS2436 Scratchpad Writes bytes to Write Scratchpad Scratchpad Copies entire contents of SP1 to NV1 Copy SP1 to NV1 Copies entire contents of SP2 to NV2 Copy to SP2 to NV2 Copies entire contents Copy SP3 to SRAM to SP3 to SRAM ...
Page 23
... The DS2436 samples the I/O line in a window from after the I/O line falls. If the line is high, a Write 1 occurs. If the line is low, a Write 0 occurs (see Figure 9). ...
Page 24
... The data line must remain at a low logic level for a minimum output data from the DS2436 is then valid for the next 14 s maximum. The host therefore must stop driving the I/O pin low in order to read its state 15 s from the start of the read slot (see Figure 9) ...
Page 25
... READ/WRITE TIMING DIAGRAM Figure 9 LINE TYPE LEGEND: Bus master active low Both bus master and DS2436 active low DS2436 DS2436 active low Resistor pullup ...
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... DETAILED MASTER READ “1” TIMING Figure 10 RECOMMENDED MASTER READ “1” TIMING Figure 11 LINE TYPE LEGEND: Bus master active low Both bus master and DS2436 active low DS2436 DS2436 active low Resistor pullup ...
Page 27
... MIN =0.4V -4 Standby Active Temperature Voltage Conversions Active EEPROM writes DQ line high impedance I state and =2.4V to 10.0V) DD TYP MAX UNITS NOTES 10 V +5.5 V =2.4V to 10.0V) DD TYP MAX UNITS NOTES 2 C 5 100 500 k DS2436 1 ...
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... CONV t 60 SLOT t 1 REC t 60 LOW0 t 1 LOW1 t RDV t 480 RSTH t 480 RSTL t 15 PDHIGH t 60 PDLOW C IN/OUT DS2436 =2.4V to 10.0V) DD MAX UNITS NOTES 10 bits 10 +85 C =2.4V to 10.0V) DD MAX UNITS NOTES 10 ms 120 s s 120 ...
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... WRITE 1 TIME SLOT 1-WIRE WRITE 0 TIME SLOT 1-WIRE READ 0 TIME SLOT 1-WIRE RESET PULSE 1-WIRE PRESENCE DETECT DS2436 ...