Subversion Repositories pentevo

::video mode from baseconf::

60hz TV: positive polarity both,
hsync period  1792
hsync on time 132
vsync period  469504 (262 lines)
vsync on time 3896, begins with hsync

hblank begins 40 clocks before hsync, ends 180 clocks after (zeros on output)
vblank begins 4 hsync periods before vsync, ends 16 hsync periods after end of vsync


60hz VGA: positive polarity both,
hsync period  896
hsync on time 106
vsync period  469504 (524 lines)
vsync on time 3896, begins next clock after hsync

hblank begins 18 clocks before hsync
hblank ends 52 clocks after hsync

=================================================
font format: 6x6, 2 EABs, format as defined in mkfont.py

frame buffer format: 8 EABS, 4096 bytes.

overall:
 60x40 chars

chars:
 placed compact in memory, total 60x40 = 2400 (0x960) bytes, each line is 60 bytes long
 start offset = 0
 charcodes allowed: 32..255

attrs:
 5 bits per attr, packed compactly in sequential bytes:

bytes: b7 b6 b5 b4 b3 b2 b1 b0 | b7 b6 b5 b4 b3 b2 b1 b0 | b7 b6 b5 b4 b3 b2 b1 b0 | b7 b6 b5 b4 b3 b2 b1 b0 | b7 b6 b5 b4 b3 b2 b1 b0 |
attrs: a4 a3 a2 a1 a0                  a4 a3 a2 a1 a0                  a4 a3 a2 a1   a0                a4 a3   a2 a1 a0
                      a4 a3 a2   a1 a0                a4   a3 a2 a1 a0                  a4 a3 a2 a1 a0                  a4 a3 a2 a1 a0

 each line has a size of 40 bytes in memory, only first 60 attrs (out of total 64) are used.
 each line starts from left-aligned attr as in picture above
 total 40*40 = 1600 (0x640) bytes
 start offset = 0x9C0

 attr format:
 a4 a3 a2 a1 a0
 b1 b0 p2 p1 p0

 {b1,b0} == background color
 {p2,p1,p0} == character color