Panasonic EURO 4 Chassis Technical Manual page 31

13.1.2.Output Control
:
Pins 9, 10, 12 - 22, 24 - 27, 29 - A17 - A0
These address lines are used to address the EPROM
IC1102 as well as the memory location for storing or
reading data from the selected memory device.
:
Pin 23 -PSEN
The Programme Store Enable output is used by
IC1102 as the EPROM enable control line.
:
Pins 28, 30 - 36 - D7 - D0
The Data lines D7-D0 allow 8 bit data to be transferred
between the EPROM IC1102
:
Pins 37 - 39 - R,G,B Output
The RGB signals output from the microprocessor
IC1101 are used to display the required teletext and
OSD information on screen. The RGB signals being
output from the following terminals:
Blue - pin 39, Green - pin 38, Red - pin 37
:
Pin 40 - Blanking
The blanking pulse output from the microprocessor
IC1101 pin 40 is used to provide the required
switching control for the teletext and OSD displays.
:
Pin 52 - ON/OFF
This output is responsible for switching the TV into
and out of standby mode. When an ON command is
received, the ON/OFF output fed from pin 52 is set
to a LOW level which is fed to the base of switching
transistor Q854.
The output from pin 52 of the microprocessor
only switches High when an OFF command is
received.
:
Pin 53 - Reset Out
To ensure correct operation of the digital ICs (VDP,
MSP), they must be started at a specific time in order
to permit signal processing. This is achieved by the
and microprocessor.
IC1101
reset control line output from pin 53 of the
microprocessor IC1101. During switch ON the digital
ICs are held LOW by
this point due to the 5V standby supply fed to the base
of Q1101 via R1112. Once the supply voltages have
become established pin 53 of the microprocessor
IC1101 pulls the base of
switching OFF, a HIGH level is then fed via R1111 to
the digital ICs initiating their start-up.
:
Pin 55 - Service
The SERVICE output control line only goes high
when the TV is switched into Service Mode. The
service control line is used to allow
programmer to be connected via AV1, allowing data
to be transferred between TV and memory
programmer or vice versa.
The programmer basically consists of an EAROM
which when connected to the AV1 socket, can talk
directly with the microprocessor
bus 1. Since pins 10 and 12 of the 21 pin AV1 socket
are available only during service mode, I
must be set to high impedance during all other
operating modes. This is achieved by disconnecting
2
the I C bus 1 from the 21 pin socket by means of two
transistors Q3006
Transistors Q3006
55 of the microprocessor IC1101, which when the
Programmer function is called up in Service Mode,
the transistors are switched ON with a High level
allowing the transfer of programming data from the
microprocessor IC1101
programmer to
mentioned earlier the transistors are switched OFF
with a Low level, thus switching pins 10 and 12 of AV1
socket to high impedance.
31
3DQDVRQLF
Q1101 which is conducting at
Q1101 LOW resulting in it
IC1101
and Q3007.
and Q3007 are controlled via pin
to programmer or from the
microprocessor IC1101.
a memory
2
via the I C
2
C bus 1
As