ds2761 Maxim Integrated Products, Inc., ds2761 Datasheet - Page 11

• Manufacturer Part Number: ds2761
• Description: Ds2761 High-precision Li+ Battery Monitor
• Manufacturer: Maxim Integrated Products, Inc.

MEMORY
The DS2761 has a 256-byte linear address space with registers for instrumentation, status, and control in
the lower 32 bytes, with lockable EEPROM and SRAM memory occupying portions of the remaining
address space. All EEPROM and SRAM memory is general purpose except addresses 30h, 31h, and 33h,
which should be written with the default values for the protection register, status register, and current
offset register, respectively. When the MSB of any two-byte register is read, both the MSB and LSB are
latched and held for the duration of the read data command to prevent updates during the read and ensure
synchronization between the two register bytes. For consistent results, always read the MSB and the LSB
of a two-byte register during the same read data command sequence.
EEPROM memory is shadowed by RAM to eliminate programming delays between writes and to allow
the data to be verified by the host system before being copied to EEPROM. All reads and writes to/from
EEPROM memory actually access the shadow RAM. In unlocked EEPROM blocks, the write data
command updates shadow RAM. In locked EEPROM blocks, the write data command is ignored. The
copy data command copies the contents of shadow RAM to EEPROM in an unlocked block of EEPROM
but has no effect on locked blocks. The recall data command copies the contents of a block of EEPROM
to shadow RAM regardless of whether the block is locked or not.
Table 3. MEMORY MAP
* Each EEPROM block is read/write until locked by the LOCK command, after which it is read-only.
ADDRESS (HEX)
1A–1F
09–0B
90–FF
02–06
12–17
20–2F
30–3F
40–7F
80–8F
0C
0D
0E
00
01
07
08
0F
10
11
18
19
Protection Register
Status Register
Reserved
EEPROM Register
Special Feature Register
Reserved
Voltage Register MSB
Voltage Register LSB
Current Register MSB
Current Register LSB
Accumulated Current Register MSB
Accumulated Current Register LSB
Reserved
Temperature Register MSB
Temperature Register LSB
Reserved
EEPROM, block 0
EEPROM, block 1
Reserved
SRAM
Reserved
DESCRIPTION
11 of 24
READ/WRITE
R/W*
R/W*
R/W
R/W
R/W
R/W
R/W
R/W
R
R
R
R
R
R
R