LP3910 Datasheet, PDF (38/72 Pages) Texas Instruments – Power Management IC for Hard-Drive-Based Portable Media Players

LP3910
SNVS481M – NOVEMBER 2006 – REVISED DECEMBER 2015
Start
CPU sends start
conversion command
to ADC
Select adc source
ADC executes
conversion request
I2C
transfers
start cid reg
data stop
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Conversion done
pulls down IRQB
line
System CPU
services IRQ
CPU reads data
start cid reg start Cid/R reg stop
CPU
sends next
Y
start conversion
command
?
N
End
start cid reg data stop
Figure 60. Data Measurement and Acquisition Sequence
8.3.6 Interrupt Request Output
The LP3910 has the ability to interrupt the system processor through the open drain IRQB pin, which transitions
to an active logic low level upon the following 8 events:
• USB Power detected
• USB disconnected
• CHG_IN Power detected
• CHG_IN disconnected
• Battery low alarm
• Thermal alarm
• ADC conversion completed
• Charger safety timer time-out
The events form the interrupt sources that correspond to a certain bit location in the interrupt request (IRQ)
register. All interrupt sources can be masked by the interrupt mask register (IMR). Masking the interrupt prevents
the interrupt event from asserting the IRQB pin, yet the event is still captured in the IRQ register, which allows
the processor to poll the interrupt sources.
After an active low IRQB has been detected by the system processor, the latter services the interrupt and
accesses the IRQ register to determine which source was responsible for the interrupt request. Reading the IRQ
register automatically clears the register to enable the capture of the next interrupt events.
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