Wednesday, May 29, 2013

Laserdisc frame number (VBI) injector board

Not to rest on our laurels, Warren and I have been hard at work at solving the problem of making Dexter replace the PR-8210 and PR-8210A for essential games such as Cliff Hanger.

The problem: games that used the PR-8210 had to read the laserdisc frame number from the video signal itself.  The frame number was encoded during the Vertical Blanking Interval.

Our proposed solution: Using the LM1881 chip to detect when the VBI starts, we are going to basically generate frame numbers in real-time using an auxilliary AVR microcontroller, some resistors and capacitors, and an "op-amp".

This prototype will hook up to an AVR ATMega 328p (which itself will be located on a mini arduino board).  This in turn will talk to the current Dexter rev2 board via TX/RX serial lines and also the LM1881 lines which are already on the Dexter rev2 board.

Assuming we are successful, we will put all of this on the final Dexter board.

In summary, this prototype board is completely awesome!

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