Rev 1059 | Details | Compare with Previous | Last modification | View Log | RSS feed
Rev | Author | Line No. | Line |
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1058 | lvd | 1 | ::video mode from baseconf:: |
2 | |||
3 | 60hz TV: positive polarity both, |
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4 | hsync period 1792 |
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5 | hsync on time 132 |
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6 | vsync period 469504 (262 lines) |
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7 | vsync on time 3896, begins with hsync |
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8 | |||
9 | hblank begins 40 clocks before hsync, ends 180 clocks after (zeros on output) |
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10 | vblank begins 4 hsync periods before vsync, ends 16 hsync periods after end of vsync |
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11 | |||
12 | |||
13 | 60hz VGA: positive polarity both, |
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14 | hsync period 896 |
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15 | hsync on time 106 |
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16 | vsync period 469504 (524 lines) |
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17 | vsync on time 3896, begins next clock after hsync |
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18 | |||
19 | hblank begins 18 clocks before hsync |
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20 | hblank ends 52 clocks after hsync |
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21 | |||
1059 | lvd | 22 | ================================================= |
23 | font format: 6x6, 2 EABs, format as defined in mkfont.py |
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24 | |||
25 | frame buffer format: 8 EABS, 4096 bytes. |
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26 | |||
27 | overall: |
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28 | 60x40 chars |
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29 | |||
30 | chars: |
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31 | placed compact in memory, total 60x40 = 2400 (0x960) bytes, each line is 60 bytes long |
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32 | start offset = 0 |
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33 | charcodes allowed: 32..255 |
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34 | |||
35 | attrs: |
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36 | 5 bits per attr, packed compactly in sequential bytes: |
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37 | |||
38 | 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 | |
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39 | attrs: a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 |
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40 | a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 a4 a3 a2 a1 a0 |
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41 | |||
42 | each line has a size of 40 bytes in memory, only first 60 attrs (out of total 64) are used. |
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43 | each line starts from left-aligned attr as in picture above |
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44 | total 40*40 = 1600 (0x640) bytes |
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45 | start offset = 0x9C0 |
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46 | |||
47 | attr format: |
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48 | a4 a3 a2 a1 a0 |
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49 | b1 b0 p2 p1 p0 |
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50 | |||
51 | {b1,b0} == background color |
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52 | {p2,p1,p0} == character color |
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53 |