Daewoo DTC-14D9T Service Manual page 31

FUNCTIONAL DESCRIPTION
Fast R, G, B insertion : The external R, G, B insertion needs a fast switching and cannot be controlled by the software
(instruction cycle of 1 sec). The fast switching pin 16 of SCART is directly connected to the TV processor pin 45 ( Fast
blanking input ). The display is synchronised with the selected video source, i.e. to get stable R, G, B signal insertion they
must be synchronised with the selected video source.
4. -Controller I/O pin configuration and function
The I/O pins of the -Controller can be configured in many ways. All port functions can be individually programmed by the
controlling software.
Each I/O port pin can be individually programmed in these configurations :
Open drain
In this mode, the port can function as input and output. It requires an external pull-up resistor. The maximum allowable
supply voltage for this pull up resistor is +5V.
So in this mode it is possible to interface a 5 Volt environment like I2C while the -Controller has a 3.3 Volt supply.
Push-Pull
The push pull mode can be used for output only. Both sinking and sourcing is active, which leads to steep slopes. The
levels are 0 and Vddp, the supply voltage 3.3Volts.
High impedance
This mode can be used for input only operation of the port.
Special port for LED
Pin 10 and 11 have the same functionality as the general I/O pins but in addition, their current source and sink capacity is
8 mA instead of 4 mA. These pins are used for driving LED's via a series current limiting resistor.
-Controller I/O pin configuration and function table
pin name
1 n.u.
2 SCL
3 SDA
4 SECAM L'
5 OCP
6 RF AGC in
7 Key in
8 S/SW
10 Red LED
11 Green LED
62 Audio mute
configuration
Stand by
High impedance High impedance
Open Drain Open Drain
Open Drain Open Drain
Push Pull / High
High impedance
impedance
High impedance High impedance
High impedance High impedance
High impedance High impedance
High impedance High impedance
High impedance Open Drain
Open Drain High impedance
Open Drain High impedance
TV on
not used
Serial clock line
Serial data line
SIF filter switching + AM/FM
switching
Over Current Protection (Switch the set
OFF if the voltage on this pin is <2.3V )
Used during ATSS to measure
7RF signal level.
Local keyboard input
external video switch
5
APPENDIX
description