Control Signal Block; Input/Output Select Ics Control Signal Block - Sony STR-DE845 Training Manual

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Table Of Contents

Table of Contents

Input/Output Select ICs Control Signal Block

DIGITAL BOARD

DIGITAL

INPUTS

FROM

IC1001

OPTICAL

IC1002

IC1003

COAXIAL

J1001

TABLE 4-1

IC1005 CONTROL LINES

PIN No.

(COAX) DVD/LD

(OPTICAL)TV/SAT

(OPTICAL)DAT/MD

(OPTICAL) DVD/LD

Circuit description

NOTE: Reference Figure 4-1 for the following circuit description:

Data, Clock and Chip Enable Lines

All control signals are supplied by IC1201 (System Control). IC1201/Pins 108 and 107 control the digital input

selection of IC1005 (pins 2 and 14). These control lines are a simple two-bit input. Table 4-1 shows the two-bit

code for the corresponding input. The resistors on the output of IC1201 (R1282 and R1281) and on the input of

IC1005 (R1006 and R1007) are easy probe points to confirm the bit pairs in the table.

The control lines for IC301, IC303 (analog input select ICs) and IC1502 (output select IC) are at IC1201/pins 46

(CE), 47 (Data) and 48 (CLK). These control signals are somewhat difficult to view due the fact that they are only

present while switching between inputs via the front panel buttons of the receiver. However, the main concern

here is that there is communications between ICs and that the actual inputs do change. Waveforms 4-1, 4-2 and

4-3 illustrate how the waveforms will appear on the oscilloscope while switching between inputs (e.g. Video 1,

Video2, DVD/LD etc). Once again, these are not exact waveforms. Confirmation of data communications

between ICs and data amplitude (5Vpp) are the important factors. All three pins (IC1201/46, 47 and 48) are at a

low state (0V) while waiting for a button to be pressed (standby state).