DS2434
ID REGISTER (80h and 81h
)
The ID Register is a 16-bit ROM register that can contain a unique identification code, if purchased from
Dallas Semiconductor. This ID number is programmed by Dallas Semiconductor, is unchangeable, and is
unique to each customer. This ID number may be used to assure that batteries containing a DS2434 have
the same manufacturer ID number as a charger configured to operate with that battery pack. This feature
may be used to prevent charging of batteries for which the charging circuit has not been designed.
CYCLE COUNTER (82h and 83h)
The cycle counter register gives an indication of the number of charge/discharge cycles the battery pack
has been through. This nonvolatile (E 2) register is incremented by the user through the use of a protocol
to the DS2434 and is reset by another protocol. The counter is a straight binary counter, formatted as
follows:
MEMORY FUNCTION COMMANDS
The protocols necessary for accessing the DS2434 are described in this section. Only these protocols may
be written to the DS2434. Writing other protocols to the device may result in permanent damage to the
part. These are summarized in Table 1, and examples of memory functions are provided in Tables 2 and
3.
PAGE 1 THROUGH PAGE 3 COMMANDS
Read Scratchpad [11h]
This command reads the contents of the scratchpad RAM on the DS2434. This command is followed by a
start byte address. After issuing this command and providing the start address, the user may begin
reading the data. The user may read data through the end of the scratchpad space (address 5Fh), with any
reserved data bits reading all logic 1s and after which the data read will be all logic 1s.
Write Scratchpad [17h]
This command writes to the scratchpad RAM on the DS2434. This command is followed by a start byte
address. After issuing this command and providing the start address, the user may begin writing data to
the DS2434 scratchpad at the starting byte address.
Copy SP1 to NV1 [22h]
This command copies the entire contents (24 bytes) of Scratchpad 1 (SP1) to its corresponding
nonvolatile memory (NV1). The nonvolatile RAM memory of the DS2434 cannot be written to directly
by the bus master; however, the scratchpad RAM may be copied to the nonvolatile RAM. This prevents
accidental overwriting of the nonvolatile RAM, and allows the data to be written first to the scratchpad,
where it can be read back and verified before copying to the nonvolatile RAM. This command does not
use a start address; the entire contents of the scratchpad will be copied to the nonvolatile RAM. The NVB
bit will be set when the copy is in progress. NV1 is made with E
2
type memory cells that will accept at
least 50000 changes.
Copy SP2 to NV2 [25h]
This command copies the entire contents (8 bytes) of SP2 (user bytes) to its corresponding nonvolatile
memory (NV2). This command does not use a start address; the entire contents of SP2 will be copied to
NV2. The NVB bit will be set when the copy is in progress. NV2 is made with E
2
type memory cells that
will accept at least 50000 changes.
Copy SP3 to SRAM [28h]
This command copies the entire contents (32 bytes) of SP3 to its corresponding SRAM. This command
does not use a start address; the entire contents of SP3 will be copied to the SRAM.
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