Nokia 3105 Servicehandbuch
RH-48
System Module
CCS Technical Documentation
Page 12
©
2003 Nokia Corporation Confidential
Issue 1 11/2003
The MIDI data stream is a unidirectional, asynchronous bit stream at maximum
31.25 kbits/sec. with 10 bits transmitted per byte (a start bit, 8 data bits, and one stop
bit).
31.25 kbits/sec. with 10 bits transmitted per byte (a start bit, 8 data bits, and one stop
bit).
MIDI data includes two categories of signals: MIDI tones and Alerting Tones. Both are
generated from DSP and send to the MIDI speaker.
generated from DSP and send to the MIDI speaker.
Audio Amplifier Interface
From audio hardware point, since the audio output from UEM is not strong enough to
produce enough power for the speaker, an audio amplifier is required.
produce enough power for the speaker, an audio amplifier is required.
The MIDI audio signal generated by the DSP and UEM audio CoDec is routed to the XEAR
output of the UEM. An audio amplifier is used to boost enough power for the speaker.
GENIO (28) is used to enable/disable the audio amplifier as needed.
output of the UEM. An audio amplifier is used to boost enough power for the speaker.
GENIO (28) is used to enable/disable the audio amplifier as needed.
Battery
Phone Battery
Introduction
An 850 mAh Li-ion battery (BL-5C) is standard in RH-48.
Interface
The battery block contains BSI resistors for battery identification. The BSI fixed resistor
value indicates the chemistry and default capacity of a battery. This resistor is connected
to the BSI pin of battery connector. Phone has pull-up resistors (R202) for these lines so
that they can be read by A/D inputs in the phone (see the following figure). There also
are spark caps in the BSI line to prevent ESD.
value indicates the chemistry and default capacity of a battery. This resistor is connected
to the BSI pin of battery connector. Phone has pull-up resistors (R202) for these lines so
that they can be read by A/D inputs in the phone (see the following figure). There also
are spark caps in the BSI line to prevent ESD.
Battery has internal protection for overvoltage and overcurrent.