NSW-6
System Module SE2
PAMS Technical Documentation
Page 27
Issue 1 12/99
Nokia Mobile Phones Ltd.
– some MCU or DSP timer expires
– DSP regular event interrupt happens
– MBUS activity is detected
– FBUS activity is detected
– Charger is connected, Charger interrupt to MAD
– any key on keyboard is pressed, interrupt to MAD
– HEADSETINT, from the switch of the headset connector (EAD)
– HOOKINT, from XMIC lines
Charging Control
Charging is controlled by MCU SW, which writes control data to CCONT
via serial bus. CCONT output pin PWMOUT (Pulse Width Modulation)
can be used to control both the charger and the CHAPS circuit inside
phone.
1 (1)
CCONT
BATTERY
MAD
System
Connector
CHAPS
Charging
Control
serial
control
Vin
PWMOU
T
To
charger
Two–wire Charging
With 2–wire charging the charger provides constant output current, and
the charging is controlled by PWMOUT signal from CCONT to CHAPS.
PWMOUT signal frequency is selected to be 1 Hz, and the charging
switch in CHAPS is pulsed on and off at this frequency. The final charged
energy to battery is controlled by adjusting the PWMOUT signal duty
cycle.
Pulse width is controlled by the MCU which writes these values to
CCONT.
Three–wire Charging
With 3–wire charging the charger provides adjustable output voltage, and
the charging is controlled by PWMOUT signal from CCONT to Charger,