Nokia NSE-3 SERIES, Service Manual

Page: 39 / 217

PAMS
Technical Documentation
NSE–3
System Module
Page 3 – 33
Original 11/97
Alert Signal Generation
A buzzer is used for giving alerting tones and/or melodies as a signal of
an incoming call. Also keypress and user function response beeps are
generated with the buzzer. The buzzer is controlled with a BuzzerPWM
output signal from the MAD. A dynamic type of buzzer must be used
since the supply voltage available can not produce the required sound
pressure for a piezo type buzzer. The low impedance buzzer is connected
to an output transistor that gets drive current from the PWM output. The
alert volume can be adjusted either by changing the pulse width causing
the level to change or by changing the frequency to utilize the resonance
frequency range of the buzzer.
A vibra alerting device is used for giving silent signal to the user of an in-
coming call. The device is controlled with a VibraPWM output signal from
the MAD2. The vibra alert can be adjusted either by changing the pulse
width or by changing the pulse frequency. The vibra device is not inside
the phone, but in a special vibra battery.
Digital Control
The baseband functions are controlled by the MAD asic, which consists of
a MCU, a system ASIC and a DSP.
MAD2
MAD2 contains following building blocks:
– ARM RISC processor with both 16–bit instruction set (THUMB mode)
and 32–bit instruction set (ARM mode)
– TI Lead DSP core with peripherials:
– API (Arm Port Interface memory) for MCU–DSP commu-
nication, DSP code download, MCU interrupt handling vec-
tors (in DSP RAM) and DSP booting
– Serial port (connection to PCM)
– Timer
– DSP memory
– BUSC (BusController for controlling accesses from ARM to API, Sys-
tem Logic and MCU external memories, both 8– and 16–bit memories)
– System Logic
– CTSI (Clock, Timing, Sleep and Interrupt control)
– MCUIF (Interface to ARM via B
US
C). Contains MCU Boo-
tROM
– DSPIF (Interface to DSP)
– MFI (Interface to COBBA AD/DA Converters)