Service manual sc-150 – Daewoo DSC-3220E/3220L User Manual
Page 53
Service manual SC-150
-52-
configuration
Stand by
TV ON
1
Power
Push Pull Low
Push Pull High
Switch OFF / ON SMPS
2
AGC
High impedance
High impedance
Tuner AGC level input –
For factory use only
5
Mod SW
High impedance
Push Pull
High = Negative
modulation, Low = Positive
modulation (L/L’).
6
SECAM L’
High impedance
Push Pull
Low = L, High =L’
7
AFC
High impedance
High impedance
ADC input
8
IR
High impedance
High impedance
Interrupt input
9
SC1 SW
High impedance
High impedance
SCART 1 slow switching –
ADC input
10
SC2 SW
High impedance
High impedance
SCART 2 slow switching –
ADC input
61
Mute
Push Pull
Push Pull
High = Mute active
62
LED
Open Drain
Open Drain
63
KB
High impedance
High impedance
Keyboard input – ADC
input
64
OCP
High impedance
High impedance
Over Current Protection –
Switch the set to Std by if < 2.
5-4-3 - Controller I/O pin configuration and function
There exist different kinds of ports. The universal ports serve as digital I/O and have additional special input and output
functions. A subset of the universal ports serves as input for the analogue-to-digital converter.
- Controller I/O pin configuration and function table
pin
name
description
To reduce power consumption in stand by mode all ports not used are configured in high impedance mode.
5-4-4 Tuning
The AFC information is supplied by the demodulator IC, and becomes available on VCT pin 7 for controlling software.
The controlling software uses this information for tuner frequency tracking ( automatic following ). The AFC window
is typically between 50 KHz and 100 KHz.
The minimum frequency step of the tuner is 50 Khz.
This AFC function is disabled when a program is tuned using the direct frequency entry or after fine tuning adjustment.
Therefore it is recommended to tune channel with the TV search function ( manual or ATSS ) or using the direct
channel entry to enable the Automatic Frequency Control.
5-4-5 Automatic Format switching and WSS
When AUTO mode is selected by the user, the television will automatically select a mode for the user. The format
information is supplied by SCART pin 8 level when in AV mode or by WSS data. The signal contains codes as defined in
the WSS European Telecommunication Standard, ETS 300 294. Briefly, the signal is received at the beginning of line