Rainbow-electronics DS2756 Manual do Utilizador descarregar pdf (Página 11)

DS2756: High-Accuracy Battery Fuel Gauge with Programmable Suspend Mode

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Table 1. PIO/DQ Pin Function

PIE IOS IE PIO

xx x x 0

PIO pin: GPIO¾Output LOW

00 x 0 1

PIO pin: GPIO¾Output High-Z, Input mode

00 0 1 1 PIO pin: Alarm Comparator Interrupt Output

00 1 1 0

DQ pin: Alarm Comparator Interrupt Output (low for t

)

PIO pin: GPIO¾Output LOW

00 1 1 1

DQ pin: Alarm Comparator Interrupt Output (low for t

)

PIO pin: GPIO¾Output High-Z, Input mode

x x 1 PIO pin: Suspend Interrupt Output

x¾Don’t care.

SUSPEND THRESHOLDS

The suspend thresholds set the current level to enter and exit Suspend mode. The threshold levels are

programmable with a magnitude range of 0 to 4mV, and are compared against the value in the Current register.

Values are programmed in two’s complement format with an implied sign bit in a virtual 9

bit position. The Charge

Suspend Threshold register is always a positive value. The Discharge Suspend Threshold register is always a

negative value.

The thresholds define an inclusive, continuous range of currents in which the DS2756 enters or re-enters Suspend

mode from Active mode. The Charge Suspend Threshold represents the minimum measured charge current which

will cause the DS2756 to transition modes. The Discharge Suspend Threshold represents the minimum discharge

current which will cause the DS2756 to transition modes.

The user values of the suspend thresholds are programmed into two bytes located within EEPROM block 0. These

memory locations serve as current threshold values only when either PIE bit is set, and can be used as general

purpose EEPROM if PIE = 00b. A copy command is required to save the byte values to EEPROM. See the

memory section for information on copying shadow RAM to EEPROM.

Figure 9. Charge Suspend Threshold Format

Address 35h

MSb LSb

15.625mV/Rsns

Figure 10. Discharge Suspend Threshold Format

Address 34h

MSb LSb

15.625mV/Rsns

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Rainbow-electronics DS2756 Manual do Utilizador Página 11