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I have salvaged this front panel from an old DVD player. It has a VFD and an IR receiver. The board runs on a PT6315 chip.

Front panel board

PT6315 chip

I know the basics of electronics and Arduinos, but I am not an expert. I want to use the VFD to make a digital clock using an Arduino through the I2C bus. The board has 13 pins to connect to:

  1. -24 V
  2. GND
  3. 3.3 V
  4. +12 V
  5. IR
  6. INOUT
  7. CS
  8. GND
  9. CLK
  10. P-LED
  11. GND
  12. SCL
  13. SDA

Pin out

What pins should I use from this to connect to an Arduino for the VFD, and is it possible to use the IR receiver as well?

Update:

A reddit user found the Service manual for the Philips DVD player I pulled this board out of . Also gave me the colour coded schematic of the front panel.

Front Panel schematic

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  • \$\begingroup\$ Since you know the driver IC, you need find the driver IC data sheet and to look at which wires from the connector go to the driver IC and then communicate with it using those wires. If the original player used the IR receiver, it is possible to use the IR receiver. \$\endgroup\$
    – Justme
    Feb 11 at 11:01
  • \$\begingroup\$ There is also a 5-pin socket in the upper corner, do you know what that went to? If that went to front panel buttons/switches you may need to implement those. As suggested in the other answers tracing out and drawing up a schematic would be helpful to find out if those connections are needed. \$\endgroup\$
    – Nedd
    Feb 11 at 11:32
  • \$\begingroup\$ Any chance you can attempt contact with the manufacturer? I pulled this VFD and found on the back this tag. From that, I was able to track down a Vice President at a new company making Aircraft products 35 years later, who had directly been involved with this device long ago. She spent her personal time tracking things down for me and was able to pull out a 16 page user manual: front info. The display still works! There are some kind folks still out there! \$\endgroup\$ Feb 11 at 22:18
  • \$\begingroup\$ @periblepsis The manufacturer is Philips. Luckily a reddit user found the service manual of the DVD player which has all the schematics and also shared the colour coded schematic for the front panel, which I have updated in the question. \$\endgroup\$ Feb 12 at 5:16

2 Answers 2

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Your Arduino can be connected to where the MCU is shown in the schematic in the drive datasheet. IC pins 6 (maybe), 7, 8, 9. Trace those pins out. Dout may not be used, just a pullup, but trace it out. The key scan is not used. Looks like there is an unrelated I2C interface for some reason on the board (SDA/SCL). The interface to the display driver is an SPI-like serial interface.

Also looks like the board uses 3.3V, so it is looking for 3.3V logic levels. If your Aruduino is 5V you should figure out what is connected to that supply and make sure it can work with 5V. Note the supply sequencing recommendations. It's not clear what the +12V is used for, trace that out. There may be some circuit to generate voltages from the +12/-24V. Also there will be filament connections to the display.

IR receivers are generally fairly standard with power and a data out. Yours may be that easy, in which case you can connect it to the Arduino and perhaps use a library function. Supply voltages should be matched though.

You've done some of the most important work in finding the driver chip datasheet, but there's still a lot of work to be done. I suggest tracing out and making a schematic from everything on that board.

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    \$\begingroup\$ The first picture in the question shows a 5 pin (FPC?) socket at the top right, labelled CON607 on the silkscreen. Might be interesting to trace if that 5 pin socket is connected to the I2C interface SDA/SCL signals. \$\endgroup\$ Feb 11 at 11:31
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Interfacing with Arduino is perfectly possible. In the past I also have recovered some Vaccum Fluorescent Displays from retired equipament for use with MSP430 and ARM Cortex MCUs in personal projects. For example this one below (the result was published in a Power Electronics Conference hosted by IEEE):

Single-Phase Induction Motor Drive (ARM Cortex-M0)

Considering the reduced schematics of that board (Front Control Board) shown below:

1. The boad is powered by +3.3 V, +12 V and -24 V. The IR (infrared receiver) and the LEDs are connected to +3.3 V. The PT6315 driver/controller is powered by +3.3 V, but note this voltage derived from +12 V and lowered to +3.3 V by a simple Zener + transistor circuit. The -24V goes directly to PT6315 (VEE) and also takes part in generation of the AC voltage for the segments (this nothing related to PT6315 - it goes directly to VFD). Finally, the +12 V rail also is used in that mentioned AC generation. So, you could use the IR receiver and the LEDs with a 3V3 Arduino board or doing a conversion level for 5 V based boards if you wish.

2. You have not mentioned how you intend to provide power (ex. battery, wall adapter or mains based) for your project. For the generation of -24 V rail, there are several different solutions, I think the simpler one would use a suitable windings of a power transformer connected to mains with standard stages of rectification and filtering. I think the best solution would be an isolated switch mode boost DC/DC converter from 12 V to 24 V. As it's isolated, you can use the OUT- pin as -24 V and OUT+ pin as GND (in this case , you lose the isolation, but this is not a problem here). I would prefer this last solution rather than a charge pump (capacitor) based auxiliary power supply, since that, for the last, the tunning for a desired voltage (losses) and ripple ends up being complex, specially under bigger currents. There are cheap isolated DC/DC modules available on market. Regarding current consumption at -24 V (VEE): In the PT6315 datasheet you can see the data below, describing the maximum consumption for the VFD grid and segments:

enter image description here

In order to cut corners and eliminate doubt as the maximum number of segments required (and at what brightness level), I recommend you use a temporary -24 V from a bench power supply and measure the current consumption. After the initial coding step - when you are able to write data on VFD) - you can switch to a power scheme more suitable for the final version.

3. The serial communication between MCU and PT6315 can be performed through SPI protocol (lines VFD-D IN/OUT, VFD-CS, and VFD-CLK. Since the PT6315 uses 3V3 for logic level, these connections are stablished for 3V3, too. Note the presence of resistors for limiting and pull-up on SPI lines.

4. The SDA and SCL lines are used for communication through I2C with a WT5701 capacitive key touch sensor, not shown on schematics below. The Front Control Board has seven PADs named PLAY/PAUSE, STOP, OPEN/CLOSE, PREV, NEXT, SOURCE and STAND BY.

5. The second pin is labeled as Wakeup signal, but the identificatin on your PCB is shown as GND. Maybe in this version, that signal is connected to GND.

6. In terms of code, there are some option that you could start as base. Note that each VFD has its own quantity / type of segments (some with area for icon animation - this is not yor case). Yo need to adapt for you VFD in particular (I saw at least a set of eight alphanumeric characters, with 13 segment each one and some inter digit separation segments, too).

6.1 Mbed 6315 driver Mbed driver (a standard library for ARM microcontrollers).

6.2 PT6315 VFD Clock and the code sample in video An Youtube video from user Jose Luis Monteiro describing the connections and discussing the code in video.

6.3 PT6315 with code on Github Other video, from the same author, with additional link to code on Github. I think you could even ask him some question, when you enter in the coding phase. Code: Link to Github code for 5.3

7. Additionaly, if you wish, there are several libraries suitable for IR decoding in Arduino envirnment (ex. NEC, RC-5. and others). It won't be difficult test for the exact protocol.

Partial schematics

enter image description here

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  • \$\begingroup\$ Thank you so much for the detailed explanation. I will try this out and let you know if it is successful \$\endgroup\$ Feb 11 at 20:27
  • \$\begingroup\$ Thank you Rajeev. The specification of the commands, timings and other communication details must be described in the datasheet. I realize you are new to this community, so, after all, if you find my effort useful, please consider voting for my answer. \$\endgroup\$ Feb 11 at 20:48
  • \$\begingroup\$ Can you please tell me how I can generate -24V power Input, I only have an option for 12V and -12V \$\endgroup\$ Feb 13 at 5:54
  • \$\begingroup\$ @Rajeev Jeganathan: I've added new data and recommendations on my answer, mainly related with the powering scheme (-24 V) and additional places where you can find code related to PT6315 VFD driver/controller - suitable to adaptation. \$\endgroup\$ Feb 13 at 12:50

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