View Full Version : TV

02-04-2007, 12:47 AM
I've heard you can connect to a TV with the propeller and display text with tv_text.spin. But how do I set up a circuit to do that? Do the parts come with the propeller education kit?

02-04-2007, 01:05 AM
its really easy you just use 3 pins and some resistors,,, look here:
I did not have the "exact" resistors but used a·series of them to get as close to the resistance as possible, i.e. 1.080k on the 1.1, so I am only off by 20 ohm or so, and my protoboard setup is just as clean a picture as my demoboard and the colors are the same.


Post Edited (bassmaster) : 2/3/2007 6:12:28 PM GMT

Dennis Ferron
02-04-2007, 01:11 AM
While your question has been answered on the forums countless times before, since I am nowhere near as good as people like Mike Green are at the advanced stuff, I'm happy to field beginner questions. http://forums.parallax.com/images/smilies/smile.gif

You can find the necessary hookup on the demo board schematic here: www.parallax.com/dl/docs/prod/prop/PropDemoDschem.pdf (http://www.parallax.com/dl/docs/prod/prop/PropDemoDschem.pdf) I used it on a breadboard and it works fine. You do have to have either an RCA jack or a video cable with an RCA end on it. What I did was I cut a video cable in half so that I could plug the male end into the TV, and plug the cut-wires end into the breadboard.

The 560 ohm resistor in the schematic really is optional. That resistor only carries the audio signal if you are setting up the Propeller to use broadcast video on channel 2 or 3 (such as if you were connecting using a "cable tv" terminal instead of RCA video) - don't bother with that. The demos run on RCA-jack type video by default and that has better quality than broadcast video anyway. If you are doing "ordinary" video output (which you will) then you will use a different method to carry audio to the TV.

For this other method of carrying audio to your TV you will need another RCA-jack cable and the circuit Paul Baker gave me: http://forums.parallax.com/showthread.php?p=627929

Just connect it to the same Propeller pin that drives the audio amplifier on the demo board schematic. You can use one for monaural sound. If you want stereo, just use 2 copies of the circuit, one for left audio and one for right audio.

Dennis Ferron
02-04-2007, 01:13 AM
I also couldn't find exact matches to the resistors, so I used some series and some parallel resistor pairs to get within 10% on each one.