Sdram - Siemens C75 Service Repair Documentation

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Copyright 2005© Siemens AG
• support for voice dialling
• handling of vocoder and voice-paths for type approval testing
• ADPCM encoder (8 kHz sampling frequency), cannot run in parallel to a speech codec
• ADPCM decoder (8 kHz and 16 kHz sampling frequency), cannot run in parallel to a
speech codec
Scheduler functions on the DSP:
The scheduler is based on an operating system. It is basically triggered by interrupts
generated by hardware peripherals or commands from the micro-controller.
communication between DSP and micro-controller
• fully automatic handling of speech channels
• semi-automatic handling of control channels
• support of the GSM ciphering algorithm (A51, A52, A53) in combination with the
hardware accelerator.
• support for General Packet Radio Services (GPRS) with up to 4 Rx and 1Tx or 3 Rx
and 2 Tx (Class 10 mobile).
• monitoring of paging blocks for packet switched and circuit switched services
simultaneously GPRS MS in Class-B mode of operation
• MMS support
• loop-back functions (according to GSM 11.10)
Real Time Clock
The real time clock (degree of accuracy 150ppm) is powered via a separate voltage regulator
inside the ASIC. Via a capacitor, data is kept in the internal RAM during a battery change for
at least 30 seconds. An alarm function is also integrated with which it is possible to switch the
phone on and off.
Measurement of Battery voltage, Battery Type and Ambient Temperature
The voltage equivalent of the temperature and battery code on the voltage separator will be
calculated as the difference against a reference voltage of the S-GOLDlite. Inside the S-
GOLDlite are some analog to digital converters. These are used to measure the battery
voltage, battery code resistor and the ambient temperature.
Timing of the Battery Voltage Measurement
Unless the battery is being charged, the measurement shall be made in the TX time slot.
During charging it will be done after the TX time slot.

5.2.2 SDRAM

Memory for volatile data. SDRAM= synchronous High data rate Dynamic RAM
Memory Size:
Data Bus:
Frequency:
Power supply:
Service Repair Documentation
Level 2.5e – C75
64 Mbit
16 Bit
105 MHz
1.8 V
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