No Subject

[jfox@xxxxxxxxxx (Jeff Fox)]

>This is interesting. The last time I read info on the F21 I thought it 
>will have only one video output, which can be either composite, or one of 
>the RGB signals. Now I see, that one F21 will be needed to produce and 
>RBG signal.
>
>How will it be done? Will each pin have 4 bits of resolution, so one will 
>have to specify a pixel with 12 bits, or the old 16 colors will apply? In 
>case one uses 12 bits, how frequently will the video coprocessor have to 
>access the DRAM? Will there bit one 20-bit read for one 12-bit pixel?

No. The video output works the same way as on MuP21, 4 pixels/word,
4 bits/pixel.  16 colors.  F21 has more pin so there will be both
composit and RGB.  There is 1 color bit on each of RGB and 1 intensity
bit shared by the three, the  same as the composite signal.

>> Analog:
>> The analog i/o coprocessor will be fast enough for 6 bit video (14 mhz)
>> but will normally be used for audio.  
>
>So if three F21s are used in concert to generate RGB video, then one 
>could in priciple go 18-bit RGB?

Yes.  We plan to try this.  We will try various resolutions in composit
and RGB as well as trying to generate video with the analog processor,
and with multiple chips using multiple analog processors.

> Higher resolution than 6 bits will
> be available with oversampling and pwm techniques.
> What is a good book for mathematically understanding those?
>--

DSP books?  I don't know take your pick.  Maybe someone else may
wish to comment, my library is pretty old.

Jeff Fox