VDR Extension Board

Overview

The core of the extension board is based on the IR Controller, but it has many additional functions: Analog video/audio outputs, digital audio outputs, status LEDs (replay, record), a video switch matrix to choose between DVB and a Linux text console on the TV, switch outputs, and more. Note that this is definitely not a simple DIY-project as the IR Controller. It is not possible to make the printed circuit boards at home, and there are more components (mostly SMD). Also, some VDR source files need to be patched or a plugin has to be written (any volunteers??) to make use of the full functionality. I just put some pictures and info here to see if some people are interested. In that case, it may be possible to order some more printed circuit boards, however, not before I have assembled one complete board to make sure that there are no errors. One set of boards made by one of the PCB prototype manufacturers costs about 75 EUR with stop masks (I mean the PCBs only, w/o components!). It will be cheaper when ordering more boards, but a reasonable price is only possible at quantities of 100+ ordered from our usual serial PCB manufacturer. The layout is actually ready and I will order the first prototype boards within the next weeks (i.e. in February 03). Please drop me a line if you have a comment or are interested to build a board: tb at tb-electronic.de

The circuit is built on two PCBs which are stacked over each other. The top PCB has all the audio and video connectors and most of the electronics, and the lower PCB has some connectors to loop back the external LPT/VGA/COM ports. This results in a very clean wiring of all the many necessary connections (there is a total of 27 connectors on the PCBs). Also, the switch outputs are placed here. Take a look here to see how it can be mouted into a VDR (should be possible to use it in a standard PC housing as well).

Requirements

ATX motherboard and power supply.
WOL connector would be great, but is not essential.
RS232 interface, preferably at a 10-pin header on the motherboard.
The software IR decoding is based on RC5, so your remote has to use this format (OneForAll URC-7040 recommended).
LIRC with special lircd.conf and lircrc.
Patches in some VDR files or a plugin
VGA graphics, VGA Timing adjusted to meet PAL specs using SVGATextMode or frame buffer device
SCART connection to TV. The video switch matrix will be useless whithout RGB connection as the VGA graphics card signal is RGB. Your primary DVB card should be a revision 1.3/1.5/1.6 with J2 connector, i.e. with RGB outputs. However, it is possible to select a mixed mode, i.e. compostite video from the DVB card and RGB video from the VGA graphics card. The TV will be switched from composite video to RGB mode automatically. (Note: I can not guarantee that all TVs do this!) Anyway, I highly recommend using a DVB with RGB outputs as the quality is much better compared to composite video (S-Video isn't much better as well). It might be possible to add RGB outputs to your card if it doesn't have the J2 connector. I haven't tried that, and I doubt that it is possible to solder a connection to the middle track (<0.1mm!) without special equipment.

Features

IR Controller (functions as described on the IR Controller page)

Uses RC5 protocol
All IR signals are forwarded to be decoded by LIRC (even non-RC5 signals)
Remote power on/off
Learning mode
Emergency reboot
Bicolor status LED

Front panel keys

Pwr key as described on the IR Controller page.
Eject key: The PIC micro will send a special RC5 code to LIRC so that a script can be called to unmount and eject disks.

Status LEDs [Top of page]

8 outputs with 25mA driver capability (2 for IR receiver bicolor status LED, 1 for 'VDR REPLAY', 1 for 'Mplayer/DVD/MP3 REPLAY', 2 for 'VDR RECORDING' (2 DVB cards), 2 still available
Brightness controlled by automatic dimmer (see 'Dimmer')

Dimmer

Brightness of LEDs and LCD backlight automatically adjusted (a LDR must be installed at the front panel to sense the ambient light intensity)
Minimum brightness adjustable by remote control

SCART output (located at the rear of the main PCB)

RGB+CS (composite sync) outputs from video switch matrix (see 'Video Switch Matrix')
All DVB video signal outputs protected by series resistors
LC-Filters in all video signal lines for improved signal quality (same values used as in the composite signal path of DVB board)
Audio outputs (see 'Analog Audio Outputs')
Switch voltage on Pin 16 (selectable by DIP switch) to invoke RGB mode of connected TV
Switch voltage on Pin 8 (selectable by DIP switch) to turn on connected TV from standby. Also, 6/12 volts may be selected under software control in case WSS (Wide Screen Signalling) is not supported by the TV.

Video Switch Matrix 3x(RGB+CS)

Dedicated remote key to select DVB video signal or Linux text console to be displayed on the TV screen
Accepts RGB+CS or composite video only from DVB (selectable by DIP switch)
Converts separate H/V sync from VGA output to composite sync (VGA display on TV will only work if the SCART input of the TV can be switched to RGB-Mode)
Optional 3rd input for external RGB+CS (for example video generator for boot splash screen with a nice VDR logo)

Analog Audio Outputs (located at the rear of the main PCB) [Top of page]

Available at separate cinch connectors and SCART
With series resistors to protect DVB board
Mute function to avoid audio 'pop' noise during power on and DVB driver load/unload

S/PDIF outputs (located at the rear of the main PCB)

Coaxial (cinch, with transformer for galvanic isolation)
Optical (TOSLINK)
Mute function (invoked by VDR remote mute key as already done with analog audio)

Loop through connectors (located at the rear of the lower PCB)

LPT 26pin to 16pin for LCD (see LCD connector)
COM1 10pin to 10pin (reserved, not used yet)
VGA 10pin to connect VGA signal to video switch matrix

Switch outputs (located at the rear of the lower PCB)

Software controllable (by VDR and/or dedicated remote keys)
Also available in standby for dedicated remote keys (outputs are pulled to GND, 500mA max., 5V standby voltage available)
4 x 12 volts/500mA (but <1A total) when VDR is running

LCD connector (internal, located on lower PCB)

Predefined wiring 26pin LPT loop connector --> 16pin connector for 4x20 chrs LCD (additional LPT signals for 4x40 displays available)
Backlight intensity controlled by automatic dimmer (see 'Dimmer')
Backlight on/off controllable by software
Display driver voltage controllable by PIC micro (to hide the arbitrary characters caused by the initialization of the LPT port during the boot process)

Extension connectors (internal, located on main PCB) [Top of page]

For extensions like more LEDs, more switch outputs, communication with other microcontrollers, etc.

Bootloader for PIC microcontroller

PIC firmware (HEX-file) can be updated in a few seconds using a small command line program under LINUX without any programmer hardware
No further interface required as it runs over the same RS232 port already used for LIRC

ICSP-Interface

For downloading the initial software (i.e. at least the bootloader). Pin RB3 for low voltage programming also available.

What's not yet implemented (design ideas only):

Separate LCD controller with PIC micro:

Using the Matrix-Orbital serial protocol to transfer the LCDproc commands (easier interfacing to PIC micro)
The PIC micro can decode the serial protocol and connects to the parallel LCD
The PIC micro can receive timer information from VDR
An RTC (software or external chip) can be implemented so that the controller can turn on VDR if a timer event occurs
Timer event(s) plus current time/date can be displayed while VDR is in standby
A low power standby supply (1 watt miniature transformer) plus SSR for controlling the ATX power supply could be added to minimize standby power dissipation (currently about 5 watts)

Here is the current layout (GND planes not shown). At first the lower PCB with the loop back connectors, below the main PCB. Quite large picture, but otherwise the resolution would be to low. [Top of page]

This is the current schematic. Even larger than the layout, but otherwise unreadable. Original size is A3. You have to scroll around... [Top of page]

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