Samsung SCH-470 Service Manual

Also see for SCH-470: Owner's manual

Contents

Samsung SCH-470 Service Manual Manual pdf 16 page image

Circuit Description5-2 Samsung Electronics5-1-3 Baseband PartMOBILE SYSTEM MODEM (MSM)The MSM equipped with the INTEL 80C186 CPUcore is an important component of the CDMAcellular phone. The MSM comes in a 176 pinsTQFP package.MICROPROCESSOR INTERFACEThe interface circuitry consists of reset circuit,address bus (A0-A19), data bus (AD0-AD15), andmemory controls (ALE, DT_R, HWR/, LWR/,RAM_CS/, ROM_CS).INPUT CLOCK¶UCPU clock: 27 MHz¶UTXCO/4 (pin 34): 4.92 MHz. This clock signalfrom the BBA is the reference clock for the MSMexcept in CDMA mode.¶UCHIPX8 : 9.8304 MHz. The reference clock usedduring the CDMA mode.BBA INTERFACECDMA, FM Data Interface¶UTXIQDATA0-7 (pins 24-32) : TX data bus usedduring both CDMA and FM mode but it is usedonly for CDMA mode at this phone.Clock¶UTC_CLK (pin 22), TX_CLK/(pin 23) : Analog toDigital Converter (ADC) reference clock used inTX mode.¶UCHIPX8 : ADC reference clock used in CDMARX mode.¶UFMCLK: TXclock used in FM mode.ADC InterfaceADC_CLK (pin 3), ADC_ENABLE (pin 1) andADC_DATA (pin 2) are required to control theinternal ADC in the BBA.Data Port InterfaceIncludes the UART. Also, supports DiagnosticMonitor (DM), HP equipment interface, downloading, and data service.CODEC InterfaceThe MSM outputs 2.048 MHz PCM_CLK (pin 19)and 8 KHz CODEC_SYNC (pin 16, 20) to theCODEC (U117). The voice PCM data from theMSM (U101) PCM_DIN (pin 135) is compressedinto 8 KHz, by QCELP algorithm in the CDMAmode.RF InterfaceTX : TX_AGC_ADJ (pin 35) port is used to controlthe TX power level and PA_ON (pin 44) signal isused to control the power amplifier. This signaldepends on the TX vocoder rate.RX : AGC_REF (pin 36) port is used to control theRX gain and TRK_LO_ADJ (pin 45) is used tocompensate the TCXO clock.General Purpose I/O Register PinsInput/output ports to control external devices.Power Down ControlWhen the IDLE/ signal turns LOW, only the TXsections will be disabled. If both the IDLE/ andSLEEP/ change to LOW, all the pins except for theTCXO and 27MHz clock are disabled.