Samsung SCH-A302 Service Manual page 46

SCH-A302
Circuit description & Circuit Diagrams
KEY MATRIX
For key recognition, key matrix is setup using KEYSENE0-2 of KEYSENSE signals and KEYSENE0-2 of
input ports of MSM. Ten LEDs and backlight circuitry are included in the board for easy operation in
the dark.
LCD MODULE
LCD module contains a controller which will display the information onto the LCD by 8-bit data from
the MSM.
(3) Baseband Part
MOBILE SYSTEM MODEM (MSM)
The MSM equipped with the QUALCOMM ARM7TDMI µ-processor is an important component of the
CDMA cellular phone. The MSM comes in a 208 pins FBGA package.
MICROPROCESSOR INTERFACE
The interface circuitry consists of reset circuit, address bus(A1-A20), data bus(D1-D16), and memory
controls (~LBE,~UBE,~LWR,~RAM_CS1,~ROM_CS,~RD,~RESIN).
INPUT CLOCK
•
CPU clock: 19.68 MHz, 32.769 kHz(sub-clock)
•
TCXO(pin A17): 19.68 MHz.
•
CHIPX8(pin 2G): 9.8304 MHz.
•
SLEEP-XTAL-IN/OUT(pins R17,T17) : 32.768 MHz
IFR INTERFACE
CDMA, FM Data Interface
•
TXIQDATA0-7 (pins 11, 12, 13, 14, 15, 16, 17, 18):TX data bus used during COMA and FM mode.
•
C_RX_IDATA0-3 (pins 45-48) and C_RX_QDATA0-3 (pins 39-42):RX data bus used during CDMA
•
FM_RX_IDATA (pin 47) and FM_RX_QDATA (pin 48):RX data bus used during FM mode.
Clock
•
TX_CLK(pin 19), TX_CLK/(pin 20):Analog to Digital Converter(ADC) reference clock used in
•
CHIPX8: ADC reference clock used in CDMA RX mode.
•
FMCLK: Reference clock in FM RX mode.
Data Port Interface
Includes the UART. Also, supports Diagnostic Monitor(DM) and HP equipment interface.
RF Interface
TX: TX_AGC_ADJ(pin 2L) port is used to control the TX power level.
The PA_ON(pin 1P) signal is used to control the power amplifier.
RX: TRK_LO_ADJ(pin 1R) is used to compensate the TCXO clock.
General Purpose I/O Register Pins
Input/output ports to control external devices.
This clock signal from the IFR is the reference clock for the MSM
except in CDMA mode.
The reference clock used during the CDMA mode.
TX mode.
SAMSUNG Proprietary-Contents may change without notice
mode.
10-2