Kevin Timmerman sent me email about having built a USB version of the closed-caption decoder that Richard Ottosen and I developed.  He used an FTDI TTL-232R cable which incorporates a USB-to-serial interface chip.  He has added many new features to the firmware, including ANSI cursor addressing, XDS, and V-chip support, and also has fixed some [...]

Got to work on the caption decoder a bit more today after all. It’s now basically working, though I may have to tweak the demodulation code a bit. Or maybe not; the errors we’re seeing may just be the result of a very poor quality video signal here in the basement of Rich’s [...]

Spent most of the day working with Rich on the caption decoder again. Probably won’t get to work on it any more before I return to California.
In the morning, Rich lugged his Tektronix 475A oscilliscope into the computer room, and things were coming together pretty well. There are debug conditionals to usurp an [...]

Worked on the new version of the caption decoder more over the last few days. Ripped out the old frame counter code, and put in a proper HH:MM:SS:FF counter, selectable for drop-frame or non-drop counting.
Rich and I started trying to get it running tonight, using the Microchip ICD2 with the “header interface” (Microchip P/N [...]

The original concept for the new version of the closed-caption decoder was that everything would be interrupt-driven, and that there would be four interrupt sources:

vertical sync from sync separator — would initialized timer 1 to count down horizontal lines
timer 1 — would count horizontal lines and interrupt at the start of line 21. handler [...]

I’m vacationing in Denver at the moment. Rich Ottosen and I are upgrading our closed-caption decoder to use a Microchip PIC16F627 rather than the PIC16C622 we previously used. The new chip has several advantages:

flash memory — the PIC16C622 was OTP.
in-circuit-debug support — requires a special bond-out adapter, though — $35 from Digikey.
hardware UART [...]