My experience with the SPI/I2C is that it always inserts at least one extra clock between consecutive bytes of data. However, you can configure a USART in sync mode and send bits directly head to tail. I have written a display generator using this trick that displays mixed graphics and text, including some simple animations. The only hardware in addition to the PIC and crystal is a couple of resistors! I get one pixel for each instruction time, so on a 40MHz PIC18 I am able to get 635 pixel times per horizontal scan line (not all of which are visible of course).. Bob Ammerman ----- Original Message ----- From: "Edson Brusque" To: Sent: Saturday, April 05, 2003 2:12 PM Subject: Re: [EE]: Video OSD generators > Hello Ned, > > >>Remember, you have two shift registers: the I2C/SPI one and the > >>UART. Either or both could be used to produce a faster bit stream. > > are you sure? How could I manipulate the start/stop bits? > > >>Plus, you can get a PIC to run at 40MHz (I'd use an 18F). > > I think bit banging is possible: > Timing for 160 pixels on a line: 52us/160 = 325ns > But full graphics can't be made on a PIC18F252: > RAM usage: (160x128)/8 = 2560bytes > > It would be a lot of effort. I would preffer a ready made solution. > Phillips have some OSD generator chips, but I can't find it on any > store. ST have the STV5730, it could be an option. > > Best regards, > > Brusque > > > > > > > -- > ----------------------------------------------------------------- > Edson Brusque C.I.Tronics Lighting Designers Ltda > Research and Development Blumenau - SC - Brazil > Say NO to HTML mail www.citronics.com.br > ----------------------------------------------------------------- > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body