A bit more video information

Richard Franks spontificus at gmail.com
Tue Nov 28 05:37:48 CET 2006

On 11/27/06, Sean Moss-Pultz <sean_mosko at fic.com.tw> wrote:
> I asked one of our hardware engineers to provide a bit more information
> about the video prospects. Here is what he said:
> "Certainly it can show some fps video. However, the LCD refresh bus
> bandwidth will be determined by LCD display size, bit per pixel, memory bus
> width, memory type ... and so on. For example, for 640x480,8bpp,60
> frame/sec, 16-bit data bus, sdram HCLK = 60MHz:
> The LCD data rate = 8x640x480x30/8 = 18.432 Mbyte/s
> LCD DMA burst count = 18.432/16 = 1.152M/s
> Pdma = (Trp+Trcd+CL+(2x4)+1)x(1/60Mhz) = 0.25(ms)
> LCD system load = 1.152x250=0.288
> So under such conditions, the neo1973 system bus occupation rate by LCD =
> (0.288/1)x100=28.8%

Ah, thanks! You know, I guess I should have started with the
user-manual link on the same page ages ago (well worth a look for
those with a thirst for info):

The figures above are optimal, but assuming I have roughly the
equivalent of a p100 or so left to play with.. plus hardware
scrolling.. expect a port of the best amiga game of all time..


It's not currently in any decent language, natch.. but I suspect that
if I create a mini-framework to dev-test in SDL and wrap any SDL
commands cleanly..  it should be a simple(ish) final port.

Hmm.. there's a lot of fun games which could be written upon this
platform.. any old-school game-writers out there?


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