Using AD5220 with SX28 (Assembly)
Yanir
Posts: 11
Hi, I'm having some trouble using the digital potentiometer AD5220 (came with a basic stamp kit) with the sx28.
The ultimate goal to generate some analog signal for tv output (NTSC), so if you have better ideas i'm open. I thought i'd try this first. I wired it up properly and tested it with my basic stamp (works) and I then just used RB.0 and RB.1 to send the sweep pattern and to set the direction. I set my sx to 40mhz to produce a 25ns instruction time (did i calc that right?) I used 25ns becuase i read the tech notes on the ad5220 and thats the time unit it uses for the sweep signal.
I'm getting some output from it but not what i expect, has anyone done this successfully? Thanks in advance.
Yanir
The ultimate goal to generate some analog signal for tv output (NTSC), so if you have better ideas i'm open. I thought i'd try this first. I wired it up properly and tested it with my basic stamp (works) and I then just used RB.0 and RB.1 to send the sweep pattern and to set the direction. I set my sx to 40mhz to produce a 25ns instruction time (did i calc that right?) I used 25ns becuase i read the tech notes on the ad5220 and thats the time unit it uses for the sweep signal.
I'm getting some output from it but not what i expect, has anyone done this successfully? Thanks in advance.
Yanir
Comments
However, you're really making things hard for yourself - it'll take you a lot of cycles to get the edges you need for sync pulses.
There's lots of good fun to be had with video on teh SX. http://www.sxlist.com/techref/ubicom/contest/video.htm has a bunch of items, and there are others.
Steve
yanir
Are you trying to do color or black and white ?
I have a black and white output device (see my sig below), that only uses two pins and two resistors.
I can provide details if you are interested.
Bean.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Check out· the "SX-Video Display Module"
www.sxvm.com
·
he talks about how to do this, follow the links at the bottom for other methods (like BW with min resistors), http://www.stanford.edu/class/ee281/handouts/lab4.pdf·is one of the more consise references I've found regarding the format of NTSC.
yanir