Datasheet

DS2781
22 of 31
PARAMETER EEPROM
Model data for the cells, as well as application operating parameters are stored in the Parameter EEPROM
memory (block 1, addresses 60h–7Fh). The ACR (MSB and LSB) and AS registers are automatically saved to
EEPROM when the RARC result crosses 4% boundaries. This allows the DS2781 to be located outside the
protection FETs. In this manner, if a protection device is triggered, the DS2781 cannot lose more that 4% of charge
or discharge data.
Table 2. Memory Map
ADDRESS (HEX) DESCRIPTION READ/WRITE
00 Reserved R
01 STATUS - Status Register R/W
02 RAAC - Remaining Active Absolute Capacity MSB R
03 RAAC - Remaining Active Absolute Capacity LSB R
04 RSAC - Remaining Standby Absolute Capacity MSB R
05 RSAC - Remaining Standby Absolute Capacity LSB R
06 RARC - Remaining Active Relative Capacity R
07 RSRC - Remaining Standby Relative Capacity R
08 IAVG - Average Current Register MSB R
09 IAVG - Average Current Register LSB R
0A TEMP - Temperature Register MSB R
0B TEMP - Temperature Register LSB R
0C VOLT - Voltage Register MSB R
0D VOLT - Voltage Register LSB R
0E CURRENT - Current Register MSB R
0F CURRENT - Current Register LSB R
10 ACR - Accumulated Current Register MSB R/W*
11 ACR - Accumulated Current Register LSB R/W *
12 ACRL – Low Accumulated Current Register MSB R
13 ACRL – Low Accumulated Current Register LSB R
14 AS - Age Scalar R/W *
15 SFR - Special Feature Register R/W
16 FULL - Full Capacity MSB R
17 FULL - Full Capacity LSB R
18 AE - Active Empty MSB R
19 AE - Active Empty LSB R
1A SE - Standby Empty MSB R
1B SE - Standby Empty LSB R
1C to 1E Reserved —
1F EEPROM - EEPROM Register R/W
20 to 2F User EEPROM, Lockable, Block 0 R/W
30 to 5F Reserved —
60 to 7F Parameter EEPROM, Lockable, Block 1 R/W
80 to AF Reserved —
B0 to B1 FSGAIN – Factory Gain Calibration Value R
B2 to FF Reserved —
*Register value is automatically saved to EEPROM during ACTIVE mode operation and recalled from EEPROM on power-up.