1.1 --- a/ULA.txt Sun Dec 11 01:11:35 2011 +0100
1.2 +++ b/ULA.txt Mon Dec 12 01:31:51 2011 +0100
1.3 @@ -1,3 +1,16 @@
1.4 +Timing
1.5 +------
1.6 +
1.7 +According to the above (15.3.2 in the AUG), there are 312 scanlines, 256 of
1.8 +which are used to generate pixel data. At 50Hz, this means that 128 cycles are
1.9 +used to produce pixel data (2000000 / 50 = 40000; 40000 / 312 ~= 128). This is
1.10 +consistent with the observation that each scanline requires at most 80 bytes
1.11 +of data, and that the ULA is apparently busy for 40 out of 64 microseconds in
1.12 +each scanline.
1.13 +
1.14 +See: The Advanced User Guide for the Acorn Electron
1.15 +See: http://mdfs.net/Docs/Comp/Electron/Techinfo.htm
1.16 +
1.17 Hardware Scrolling
1.18 ------------------
1.19