Datasheet

DS2438
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Page 1 (01h)
The second page, Page 1, contains the ICA, elasped time meter, and current offset data. Both the ETM
and ICA are volatile read/write locations so that they may be set, changed, or cleared by the host
software. Bytes 0-3 contain the ETM data, formatted as described in the “Operation - Elapsed Time
Meter” section. Byte 4 contains the 8-bit ICA. Bytes 5 and 6 contain the Offset Register data. Byte 7 is
reserved and will read out as all “1”s.
Page 2 (02h)
The third page of memory (Page 2) contains the Disconnect (first 4 bytes) and End of Charge (remaining
4 bytes) timestamps. This page is volatile and read/write. Refer to the “Operation – Elapsed Time Meter”
section for the formatting of these locations.
Pages 3-7 (03h - 07h)
The remainder of the memory in the DS2438 (Pages 3 through 7) is backed with EEPROM. This memory
provides 40 bytes of user memory which may be used to carry any information the user wishes to store.
Additionally, the CCA/DCA information is stored in bytes 4-7 of page 7 if the DS2438 is configured
appropriately. If the CCA/DCA is used, page 7 should not be written to or current accumulator data will
be overwritten. See “Operation-Current Accumulators” for details.
MEMORY MAP Figure 7
PAGE BYTE CONTENTS R/W NV PAGE BYTE CONTENTS R/W NV
0 STATUS/
CONFIGURATION
R/W YES 0 USER BYTE R/W YES
1 TEMPERATURE
LSB
R NO 1 USER BYTE R/W YES
2 TEMPERATURE
MSB
R NO 2 USER BYTE R/W YES
0 3 VOLTAGE LSB R NO 3 3 USER BYTE R/W YES
4 VOLTAGE MSB R NO 4 USER BYTE R/W YES
5 CURRENT LSB R NO 5 USER BYTE R/W YES
6 CURRENT MSB R NO 6 USER BYTE R/W YES
7 THRESHOLD R/W YES 7 USER BYTE R/W YES
0 ETM BYTE 0 R/W NO 0 USER BYTE R/W YES
1 ETM BYTE 1 R/W NO 1 USER BYTE R/W YES
2 ETM BYTE 2 R/W NO 2 USER BYTE R/W YES
1 3 ETM BYTE 3 R/W NO 3 USER BYTE R/W YES
4 ICA R/W NO 4 4 USER BYTE R/W YES
5 OFFSET LSB R/W YES 5 USER BYTE R/W YES
6 OFFSET MSB R/W YES 6 USER BYTE R/W YES
7 RESERVED 7 USER BYTE R/W YES
R/W NO
0 DISCONNECT
BYTE 0
R/W NO · · · · ·
1 DISCONNECT
BYTE 1
R/W NO · · · · ·
2 DISCONNECT
BYTE 2
R/W NO · · · · ·
2 3 DISCONNECT
BYTE 3
R/W NO 0
USER BYTE
R/W YES
4 END OF CHARGE
BYTE 0
R/W NO 1
USER BYTE
R/W YES
5 END OF CHARGE
BYTE 1
R/W NO 2
USER BYTE
R/W YES
6 END OF CHARGE
BYTE 2
R/W NO 7 3
USER BYTE
R/W YES
7 END OF CHARGE
BYTE 3
R/W NO 4 USER BYTE/
CCA LSB
R/W YES
5 USER BYTE/
CCA MSB
R/W YES
6 USER BYTE/
DCA LSB
R/W YES
7 USER BYTE/
DCA MSB
R/W YES