OfficeServ 7100 Service Manual© SAMSUNG Electronics Co., Ltd. 2-25y The highway channel in the 4SLM board is determined by the SPI command in softwareand reads/writes only the channel information required for the system highway through74LCX125 by using the TSAC signal provided from Le88241.y SPI: The 4SLM board is controlled via the SPI interface provided by the UNI board.SPI_DIO/SPI_SCK/SPI_CS are provided by the UNI board and DIN/DOUT pins arehardwired in Le88241 to make the same signal path for Data In/Out.y All controls for the 4SLM board are performed through the register setting and theinformation reading of Le88241.Dual ABS PartThe 4SLM board performs the SLT interface function by using Le88241, which is 2-ChannelAuto Battery Switching(ABS) one-chip solution chip by Legerity Inc. The Le88241provides the 2-port SLT interface and embeds the Sine wave ringing generation circuit sothe separate ring generation circuit is not required. Up to three boards can be mounted onthe UNI board. The board is controlled by the MP10/11 board bia the UNI boards by usingthe SPI bus. The most operations and functions of the 4SLM board are determined byLe88241.The major features of Le88241 as follows:y Sine Wave Ringing Generationy DC Feedingy Loop supervision detectiony 2/4-wire balancey Transmit/receive gain controly A-law/u-law selectionThe Le88241 consists of the following blocks:y Digital Interface BlockThis is the interface block with the microprocessor. The L288241 provides GCI modeor PCM/MPI and the 4LSM board uses PCM/MPI Mode, i.e. Voice PCM and Data MPIseparated. In Digital Interface, the PCM/MPI Mode is selected by applying ‘1’ to theCS-PG pin or a clock to DCLK. A mode is selected by supplying DCLK in the 4SLMboard. The MPI Interface uses the SPI bus. DU/DD, i.e. Data in/out, are separated inthe Le88241, but the two pins are connected in the outside of the chip in term ofhardware and is used as the DIO pin.y PCM Interface BlockDRA, DXA, CLK and FS pins are in charge of the PCM interface and channels areselected by using the SPI command. When the required channel is accessed, theLe88241 creates the time slot control signal. In addition, the 4SLM board allows thecorresponding channel to access to the system highway by controlling the signal byusing 3-state buffer.
