I saw some 65xx-based SBC projects, and some are using the 6545 CRT video controller. This thing seems to be used rather often.
But a possible replacement could be the MOS 8563 Video Display Controller (VDC). It's the one used in the C128 and the B900. The main advantage is that this chip is very easy to get. It runs independendly from the computer with a 16 MHz clock and has its own 64K video memory. The VDC is rather flexible, it has 36 registers with a lot of settings for size, position, synchronization, graphic modes, memory access and whatever. There's something special on this chip: It is indirectly programmed. The registers are not present in memory, the VDC only uses two bytes. In the C128 it is located at $D600 and $D601. To write a register, write the register number in $D600 and the value in $D601. To read a register, set the value in $D600 and read $D601. Without writing a value in $D600, a status byte can be read. This seems rather complicated, but it is a lot possible with this chip. Because it has only two registers and it's own video RAM, it would be possible to create a dual-monitor system with only using 4 bytes in the adress room, and no loss of video memory because the VDC has its own RAM. The video output is RGBI-Digital (16 colors) with TTL level and H/V sync. A monochrome composite signal is also available. In commodore128.org a small board was created to convert the RGBI signal into RGB-Analog, from there it could be convertered to Composite, S-Video or VGA. A monitor capable of displaying 15kHz or a scandoubler is still neccessary, though. Note: There's also a VDC 8568 from the C128DCR (desktop in metal case) with has a different pin layout and one register more. But it is not fully compatible to the 8563 and more difficult to get.
The VDC was intended to make the C128 business-compatible, it was also neccessary for CP/M. It is normally designed to display 80x25 character text mode in 16 colors. Reversed, blinking and underlined charaters are directly supported, the cursor shape can be modified. The VDC uses a character set in its video RAM, it has to be copied to it first. Of course the characters are completely user-definable, they could even be modified if the RAM contens of the charset are changed. If you know the method on Commodore computers two switch between the upper chars/graphics and lower/upper chars character sets by pressing the Commodore and the Shift keys, normally all characters are changed. This doesn't happen on the VDC, it can display both charsets. There are also interlaced text displays with 80x50 or more possible. All 16 colors could be used at the same time. The screen has one color, it also could be used with inverted colors.
Of course the VDC has real graphics modes. Standard is 640x200, but it reaches up to 752x700 interlaced (monochrome). Color is possible, but then the resolution must be lower. It can use all 16 colors with two colors in an 8x8 cell without tricks. The VDC has special block-moving commands as well as hardware-scrolling. Sprites or raster-interrupts like on the VIC-II are not available. With tricky programming, 136-color modes are available, or more complicated VDC-FLI modes with 640x480 pixels interlaced for high color display.
There's no real datasheet available, but there's a lot in the internet or check out the C128's programming guides. For tricks and specialized I can recommend commodore128.org. There's also a big thread about connecting the VDC to modern devices. Here are some additional infos:
Wikipedia:
http://en.wikipedia.org/wiki/MOS_Technology_8563Graphic Booster:
http://www.commodore128.org/index.php?topic=3082.0Two VDC-FLI-Images:
http://www.bilder-hochladen.net/files/b ... x-cb70.jpghttp://www.bilder-hochladen.net/files/b ... w-e4a6.jpgAnd the VDC-part of the C128-Demo 'Risen from Oblivion':
http://www.youtube.com/watch?v=sW4V-ehYFQw
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