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I am wondering if anyone out there has tried replacing a VFD display with a modern LED or OLED display. I would like to hack my factory car stereo (Clarion) which uses a VFD with an Arduino and an LED display.

I've already taken apart the head unit and removed the VFD. The following inputs/outputs are silk screened on the VFD electronics:

VFD-GND VFD+32V F+6V ILL+ ILL- SYS+5V VFD-CS VFD-CP VFD-DA V/K-RESET KEY-DI KEY-CE KEY-CL KEY-DO KEY-DI VOL1-L VOL2-L TONE-SW CD-LOAD CD-EJECT POWER-SW VOL1-R VOL2-R U-GND

A lot of the signals are self-explanatory but the VFD ones I'm not totally familiar with. I would like to reverse engineer the signals coming out of the radio and have the Arduino translate the signals and output them to an LED display. I'm unsure what kind of signals the VFD uses for communication. Anybody have a suggestion where to start?

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  • \$\begingroup\$ Looking at the inputs I suspect the VFD has a microcontroller that interprets these inputs? While it might be possible to probe the inputs with a scope and interpret them with an arduino. I would think it's a very time consuming task. plus the VFD would be quite visible in daylight so your replacement LED display may not be as easy to read. \$\endgroup\$
    – BenG
    Sep 13, 2015 at 22:28
  • \$\begingroup\$ Yeah looks like the VFD connector is going to a M30873MHA MCU. I know there are some VFD libraries for the Arduino already, I was thinking maybe I could somehow use those in conjunction with the Arduino to interpret the signals from the MCU. \$\endgroup\$
    – sam
    Sep 13, 2015 at 22:45
  • \$\begingroup\$ Well you are in luck looks like Renesas still provide the documentation. So if you can work out a schematic for your vfd board you might be able to work out what the micro was expecting. Good luck. But if it were me I would be looking at building a custom arduino/raspberry pi media centre rather than trying to retrofit. \$\endgroup\$
    – BenG
    Sep 13, 2015 at 22:52

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I saw 5 VFD-related signals from your list: VFD-GND VFD+32V VFD-CS VFD-CP VFD-DA. GND and +32V are pretty self-explanatory.

Googling for "CS CP DA vfd" gives datasheet for ML3289 / ML3288: http://www.lapis-semi.com/en/data/datasheet-file_db/display/FEDL9289-01.pdf

Thus, the VFD controller has SPI interface (where SI is called "CP" for some reason) with a somewhat complex command protocol. Read datasheet for details on protocol. You will want to use "arduino SPI slave" library.

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  • \$\begingroup\$ That is some seriously impressive detective work. \$\endgroup\$
    – 0xDBFB7
    Sep 14, 2015 at 11:41
  • \$\begingroup\$ Thanks theamk, I'll try loading up an SPI library for Arduino and eventually dump the output to the serial window. I stumbled across the other signals KEY-CL, KEY-DO, etc. on a different data sheet for a LC75700 which is actually on the VFD electronics too. According to the datasheet it is a "Key scan IC", probably for all the buttons on the front panel. Some more digging found that CL, DO, CE, is also used in the CCB protocol used one some radios: github.com/RodLophus/SanyoCCB Once I get it wired up I'll see if I can manipulate the radio with that Arduino library. I'll post my result \$\endgroup\$
    – sam
    Sep 15, 2015 at 4:21

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