Rainbow Electronics DS2784 User Manual

Ds2784, General description, Applications

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The model is constructed with all points normalized to the fully charged state at +40°C. All values are stored in the cell parameter EEPROM block. The +40°C full value is stored in µVhr with an LSB of 6.25µVhr. The +40°C active empty value is stored as a percentage of +40°C full with a resolution of 2-10. Standby empty at +40°C is, by definition, zero and, therefore, no storage is required. The slopes (derivatives) of the 4 segments for each model curve are stored in the cell parameter EEPROM block as ppm/°C. The breakpoint temperatures of each segment are stored there also (see Application Note 3584: Storing Battery Fuel Gauge Parameters in DS2780 for more details on how values are stored). An example of data stored in this manner is shown in Table 6.
This command is structured the same as the compute MAC without ROM ID, except that the ROM ID is included in the message block. With the ROM ID unique to each DS2784 included in the MAC computation, the MAC is unique to each token. See White Paper 4: Glossary of 1-Wire SHA-1 Terms, for more information. See Figure 9 for command timing.