Pioneer PDP-506PE Service Manual page 90

1
A
M62334FP (HD DIGITAL ASSY : IC3157)
• 8-bit 4ch I2C Bus D-A Converter with Buffer Amplifier
Pin Arrangement (Top view)
AO1 1
AO2 2
B
AO3 3
4
AO4
Block Diagram
VCC
8
POWER ON
C
RESET
8bit Latch
8bit Upper
Segment R-2R
D
1
AO1
TC74VHC123AFTS1 (HD DIGITAL ASSY : IC3160)
E • Dual Monostable Multivibrator/AFN/AFT Retriggerble
Pin Arrangement (Top view)
1A 1
1B 2
1CLR 3
1Q 4
2Q 5
2Cx 6
F
2Rx/Cx 7
GND 8
90
1
2
8
VCC
7 SCL
6 SDA
5
GND
SCL SDA
7 6
I2C BUS TRANSCEIVER
CHANNEL
DECODER
8
8bit Latch 8bit Latch
8bit Upper 8bit Upper
Segment R-2R Segment R-2R
2 3
AO2 AO3
16
Vcc
15
1Rx/Cx
14
1Cx
13
1Q
12
2Q
11
2CLR
10 2B
9
2A
PDP-506PE
2
3
Pin Function
No. Pin Name
1 AO1
2 AO2
8-bit resolution D-A converter output
3 AO3
4 AO4
5 GND Ground
6 SDA Serial data input
7 SCL Serial clock input
8 VCC Power supply
GND
5
8bit Latch
8bit Upper
Segment R-2R
4
AO4
Truth Table
Inputs Outputs
A B CLR Q
H H
X L H L
H X H L
L H
L H
X X L L
X: Don't care
3
4
Pin Function
Note
Q
Output enable
H Inhibit
H Inhibit
Output enable
Output enable
H Reset
4