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Note that the output of the Wide Band Preamp
Serial Data Lines
Figure 4-4 shows the Serial Data lines and indicates what circuits they control. ICs IC7B00~IC7B03 are level shift ICs, changing the 3.3V data and clock lines from IC7A00 to 5V lines.
In previous sets the TV Control circuitry used two E2PROM Memory ICs, one on the
In the V23 the DTV Tuner and Modulator are separate from the DM Module. The DTV Tuner is controlled by the TDAT and TCLK lines from the DM Module. The DM Module also controls the MLink (DVI) circuitry, through the
Figure 4-4 also shows that the DM Module receives and processes the signals from the Card Reader.
µPC Parallel Inputs
The parallel inputs to the µPC are status inputs or sig- nals inputs required for control purposes.
AC-OFF Input
Informs the µPC if AC Power is lost. The monitoring circuit is shown in Figure
If AC power is lost, Q9A10, PC9A10 and Q7A20 all quit conducting, allowing pin 20 of IC7A00 to go High. This informs the Control circuitry power has been lost. The µPC responds by rapidly storing all user program- ming and service adjustments to memory. It also out- puts a High on the Power Good line, informing the DM of the power loss.