Post by thread:Video Overlay

GRAEME SMITH email: spam_OUTgrysmithTakeThisOuTfreenet.edmonton.ab.ca YMCA Edmonton Address has changed with little warning! (I moved across the hall! :) ) Email will remain constant... at least for now. On Mon, 22 Mar 1999, Kevin wrote: > I have a question for you Pic wizards, How can I display text > on a monitor and /or TV. > It depends on the Monitor, or T.V. Perhaps the easiest application, is the one used for Monochrome monitors such as the old green, or amber screens that everyone is dumping in the dump these days. A Hercules card, I slightly disremember, had a graphics buffer, that contained an image of the whole screen, one bit per pixel. This was then read out to the screen, using a serial shift register one byte at a time, and the sync signals added in extra.... I remember it, because the shift register had a bad pin, and I replaced it to see if I could get it to work.... That didn't work because the character generator rom, which was used to print the character into the screen buffer in its graphics form, had a bad pin on it too. When I transferred the character generator rom, to a new eprom, all the problems went away.... Your mileage may vary ;) Grey

> I have a question for you Pic wizards, How can I display text > on a monitor and /or TV. > > Is there a single chip hardware interface or somewhat easy > interface to implement for overlay onto a Monitor??? > Wirz Electronics has product that seems like it might work for you. Haven't used it myself; just ran across it in my searching for pic info--still at the blinking LED stage. http://www.wirz.com/video/index.html shawn

Hi Kevin, > I have a question for you Pic wizards, How can I display text > on a monitor and /or TV. > > Is there a single chip hardware interface or somewhat easy > interface to implement for overlay onto a Monitor??? > > KD See http://www.efd.lth.se/~e96rg/pic.html ; this guy is using an overclocked (12 MHz ?) PIC16F84 do drive a pal TV directly (?) and as I remember he's also doing some text display. Stefan Sayer

Well I hooked it up. There is something on the screen, but its not in sync there are dots all over the screen. I have tried the PIC Dream also with similar results. I have never worked with video so I really dont know how to correct the problem. Anyone have any Ideas??? Kevin >See http://www.efd.lth.se/~e96rg/pic.html ; this guy is using an >overclocked (12 MHz ?) PIC16F84 do drive a pal TV directly (?) and as I >remember he's also doing some text display. > >Stefan Sayer

GRAEME SMITH email: .....grysmithKILLspam@spam@freenet.edmonton.ab.ca YMCA Edmonton Address has changed with little warning! (I moved across the hall! :) ) Email will remain constant... at least for now. On Wed, 24 Mar 1999, Kevin wrote: > Well I hooked it up. There is something on the screen, but its not in sync > there are dots all over the screen. I have tried the PIC Dream > also with similar results. I have never worked with video so I > really dont know how to correct the problem. > > Anyone have any Ideas??? > Probably not a PAL t.v. NTSC maybe? remember there are competing standards Europe uses one, Ahem.... America uses another. Gotta watch the assumptions. Grey