The Baseband architecture is basically similar to DCT3 GSM phones. HD947 differs from DCT3 in the single pcb concept and the serial interface between MAD2PR1 and COBBA_GJP and between MAD2PR1 and CCONT.
In HD947 the MCU, the system specific ASIC and the DSP are
Technical Documentation integrated into one ASIC, called the MAD2PR1 chip, which takes care of all the signal processing and operation controlling tasks of the phone.
The Baseband architecture supports a power saving function called "sleep mode". This sleep mode shuts off the VCTCXO, which is used as system clock source for both RF and Baseband. During the sleep mode the system runs from a 32 kHz crystal.
The phone is waken up by a timer running from this 32 kHz clock supply. The sleeping time is determined by some network parameters. When the sleep mode is entered both the MCU and the DSP are in standby mode and the normal VCTCXO clock has been switched off.
The battery voltage in HD947,called Vb, is 1.8V to 3.6V depending on the battery charge amount. The battery voltage is up converted to one of 4 voltage levels in the range from 3.1 V to 4.2 V, called Vdc_out, by means of a DC/DC converter. The nominal level of the four Vdc_out voltages, depends upon the required power level of the RF. The DC/DC converter is always operating, provided that the input supply is greater than 1.8V and with sufficient current capability.
The main part of the Baseband is running from 2.8V power rails, which is supplied by a power controlling asic, CCONT.
The supply, Vcobba, for the analog audio parts, and the supply Vbb for the main digital parts of the Baseband along with Vcore as supply possibility for the core of MAD2PR1.
In the CCONT asic there are 7 individually controlled regulator outputs for the RF-section. In addition there is one +5V power supply output (V5V), also supplied to the RF.
The CCONT also contains a SIM interface, which supports both 3V and 5V SIM-cards. The SIM is supplied from a separate regulator, VSIM, in CCONT.
A real time clock function is integrated into the CCONT, which utilizes the same 32kHz clock supply as the sleep clock. The supply for the RTC is taken directly from Vdc_out. Which means that when the battery is removed the RTC may have to be set again at power up. However the RTC will run for at least 24h after the phone has cut off due to low battery power. Last but not least the CCONT supplies a 1.5V reference voltage, Vref, for AD-converter usage in the Baseband and as reference voltage to the RF.
The COBBA_GJP asic provides A/D and D/A conversion of the in-phase and quadrature receive and transmit signal paths to the RF along with AFC frequency control, AGC receiver gain control and TXC transmitter power control. The remaining RF control signals are supplied by the MAD2PR1, i.e. BAND_SEL for selection between 900 or 1800 MHz band, FrACtrl for amplification control in the receiver front end, and tree signals
Technical Documentation System Module for the control of the RF synthesizer.
The COBBA_GJP asic also provides A/D and D/A conversions of received and transmitted audio signals to and from the internal and external audio transducers.
Data transmission between the COBBA_GJP and the MAD2PR1 is implemented using two serial busses, SERRFI for RF digital data and COBBA_GJP control. PCM for digital audio data. Digital speech processing is handled by the MAD2PR1 asic. Last but not least the COBBA_GJP emits the backlight control signals to the UISWITCH IC, which drives the keyboard- and LCD backlight LEDs.
The Baseband supports 3 microphone inputs together with 2 earphone outputs.
The mic inputs can be taken from an internal microphone, a headset microphone or from an external active microphone signal source. The microphone signals from different sources are connected to separate inputs at the COBBA_GJP asic.
The output for the internal earphone is a dual ended type output capable of driving a dynamic type speaker. Input and output signal source selection and gain control is performed inside the COBBA_GJP asic according to control messages from the MAD2PR1. Keypad tones, DTMF, and other audio tones except ringing alert are generated and encoded by the MAD2PR1 and transmitted to the COBBA_GJP for decoding.
MAD2PR1 generates a PWM output for the buzzer and a logical high/low signal for driving the internal vibra motor. These control signals together with light control are fed to the UIswitch which drives the backlight, vibra and buzzer units.
The MAD2PR1 communicates via an IIC bus with the EEProm which contains all user changeable data and tuning values. Additionally the memory of HD947 is made up of a FLASH Rom and a SRAM for MCU memory, both sharing a common address- data bus. The DSP memory is completely integrated into the MAD2PR1 asic.
Two wire and three wire chargers can be connected to the phone. Three wire chargers are equipped with a control input, through which the phone gives PWM charging control signal to the charger. The battery charging is controlled by two different PWM signals, one from CCONT to the charger, CHARG_CTRL, and one from MAD2PR1 to PSCC, PSCC_PWM.
The CHARG_CTRL, is constant 25%, to make the phone the master in case it's inserted into a DCH-9 deskstand.
The PSCC_PWM duty cycle is determined by the charging software.
A 84 by 48 dot matrix LCD is connected via a zebra connector. The MAD2PR1 commands the display driver via a serial write only interface.
Was this article helpful?
You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.