1.1 --- a/README.txt Mon Apr 15 17:53:50 2019 +0200
1.2 +++ b/README.txt Thu May 02 23:21:07 2019 +0200
1.3 @@ -101,39 +101,6 @@
1.4
1.5
1.6
1.7 -VGA Output Example Comparison
1.8 -=============================
1.9 -
1.10 -In investigating different techniques, the following observations have been
1.11 -made about the behaviour of the different VGA examples:
1.12 -
1.13 - DMA Horizontal Picture Pixel Scrolling
1.14 - Channels Resolution Stability Consistency Operational
1.15 - -------- ---------- --------- ----------- -----------
1.16 -vga 1 High No No Yes
1.17 -vga-cpu 0 High Yes Yes Yes
1.18 -vga-dual 2 High No No No
1.19 -vga-pmp 1 High No No Yes
1.20 -vga-timer 2 Low Yes Yes Yes
1.21 -
1.22 -Here, picture stability is assessed with the CPU accessing RAM. In general,
1.23 -all of the approaches can provide stable pictures with limited RAM access
1.24 -loading. However, under load, the picture will stretch and ripple for all
1.25 -examples where picture stability is given as "No".
1.26 -
1.27 -It should be noted that the vga-timer example employs two DMA channels, but
1.28 -this is only to maximise horizontal resolution. With a single channel,
1.29 -horizontal resolution is diminished still further in comparison to the other
1.30 -examples.
1.31 -
1.32 -It would appear that two most viable approaches are the vga-cpu and vga-timer,
1.33 -if only because they produce consistently-sized pixels, retain picture
1.34 -stability under load, and provide operational horizontal scrolling. These
1.35 -approaches provide a tradeoff between performance (vga-timer being faster) and
1.36 -resolution (vga-cpu being better).
1.37 -
1.38 -
1.39 -
1.40 References
1.41 ==========
1.42