Pioneer KEX-900 Service Manual page 21

© Funetion of terminals (TC9177P)
34 =>, Go= (81 07/,4 > Gis 0/8)
In the unit's circuitry, input and output of Lch and Rech are used in
reverse.
Terminal
Name
/O
Function and operation
2,3 L-Loudness 1, 2 ! Output Loudness terminal
19,18
R-Loudness 1, 2
When loudness data is input, this terminal will be —20 dB tap terminal.
Loudness is controlled by the high-low boost circuit connected to this
terminal.
4 L-OUT1
Output
10dB step attenuator output
"y
17 R-OUT1
Signai with IN is attenuated from 0 to 70 dB in8
steps at the 10 dB step. |
5 L-IN4 Input 10 dB attenuator input
16 R-IN4
i
6,15 A-GND | AC ground terminal
4
7 L-IN2 Input 2 dB attenuator input
14 R-IN2
a
8 L-OUT2 Output 2 dB attenuator output
13 R-OUT2
Signal with IN is attenuated from O to 8 cB in 5 steps at the 2 dB step.
11 DATA
Input
Data input of attenuation amount and chnnel selection
Consisting of 20 bits, it is input by the CK signal.
aaa 2
10 CK Input Clock input
Clock input to fetch.data of the DATA terminal.
12 ST Input Strobe input
L-LOVOMESS 1
L -LOUONESS2
Lor!
LEVEL Sef TER
LATCH CRCUT
LEVEL SHE TER
Attenuation amount and channel selection data fetched from the DATA and
CK terminal can be latched by having this terminal set to ''H'' level, If ''H''
level is not applied to this terminal, the previous data will be in effect.
(+) power applied terminal
Ground terminal
(—) power applied terminal
The TC9177P is a built-in electronic volume IC for loudness
ON/OFF. The attenuation volume data output by the system
controller (1C3), is input to the DATA, CK, and ST termi-
nals. The data consists of 20 bits. It consists of the follow-
ing.
Description
Selection of L channel, R channel
Bit for loudness ON/OFF. ''1"' is ON, and''0"
is OFF.
Setting of 2 dB step attenuator
Setting of 10 dB step attenuator
Chip select bit
"0001" is select mode, for values othe r than
{15 ]-a-cr0 this, there is no operation.