Service Manual 3. Baseband Section
10
3.2.5 Interface Distribution
3.2.5.1 PLL Interface
OMAP-L138 has SPI for connecting PLL SKY72310 (U7000) and this interface is controlled
by DSP. SKY72310 works in slave mode and its SPI timing is shown in Figure 3-4.
Figure 3-4 SPI Timing of SKY72310
3.2.5.2 IF Processor Interface
The IF processor AD9864 (U6002) is composed of two digital interfaces: SPI and SSI. SPI is
used to configure AD9864 and read configuration data. SSI is used to output I and Q
demodulation data and AGC data. AD9864 works in SPI slave mode and DSP works in SPI
master mode. SSI is connected to the RX end of McBSP1 on OMAP-L138, AD9864 works in
master mode, and DSP on OMAP-L138 works in slave mode.
3.2.5.3 DAC Interface
TLV5614 (U4000) is a 12-bit DAC that consists of four channels and provides a 4-wire serial
interface for connecting to the TX end of McBSP1on OMAP-L138. U4000 is controlled by
DSP and works in slave mode.
3.2.5.4 RTC Interface
The button cell (BT2000) is adopted to supply power to OMAP-L138 RTC, so that the RTC
will operate properly even if the battery is removed.
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