Rainbow Electronics DS2788 - Manual (Page 17)

The Status register contains bits that report the device
status. The bits can be set internally by the DS2788.
The CHGTF, AEF, SEF, LEARNF, and VER bits are
read-only bits that can be cleared by hardware. The
UVF and PORF bits can only be cleared through the 1-
Wire interface.
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Stand-Alone Fuel-Gauge IC with
LED Display Drivers
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ADDRESS 01h BIT DEFINITION
Field Bit Format Allowable Values
CHGTF 7 Read Only
Charge Termination Flag
Set to 1 when: (VOLT > VCHG) and (0 < IAVG < IMIN) continuously for a period
between two IAVG register updates (28s to 56s).
Cleared to 0 when: RARC < 90%
AEF 6 Read Only
Active Empty Flag
Set to 1 when: VOLT < VAE
Cleared to 0 when: RARC > 5%
SEF 5 Read Only
Standby Empty Flag
Set to 1 when: RSRC < 10%
Cleared to 0 when: RSRC > 15%
LEARNF 4 Read Only
Learn Flag—When set to 1, a charge cycle can be used to learn battery capacity.
Set to 1 when: (VOLT falls from above VAE to below VAE) and (CURRENT > IAE)
Cleared to 0 when: (CHGTF = 1) or (CURRENT < 0) or (ACR = 0**) or (ACR
written or recalled from EEPROM) or (SLEEP Entered).
Reserved 3 Read Only Undefined
UVF 2 Read/Write*
Undervoltage Flag
Set to 1 when: VOLT < V SLEEP
Cleared to 0 by: User
PORF 1 Read/Write*
Power-On Reset Flag—Useful for reset detection, see text below.
Set to 1 when: upon power-up by hardware.
Cleared to 0 by: User
Reserved 0 Read Only Undefined
*This bit can be set by the DS2788, and can only be cleared through the 1-Wire interface.
**LEARNF is only cleared if ACR reaches 0 after VOLT < VAE.
Figure 14. Status Register Format
Calculation of Results
RAAC [mAh] = (ACR[mVh] - AE(T) × FULL50[mVh]) × RSNSP [mhos]
RSAC [mAh] = (ACR[mVh] - SE(T) × FULL50[mVh]) × RSNSP [mhos]
RARC [%] = 100% × (ACR[mVh] - AE(T) × FULL50[mVh]) / {(AS × FULL(T) - AE(T)) × FULL50[mVh]}
RSRC [%] = 100% × (ACR[mVh] - SE(T) × FULL50[mVh]) / {(AS × FULL(T) - SE(T)) × FULL50[mVh]}
Status Register