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MOS Technology VIC
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<h2 id="registers">Registers</h2> <p>The VIC has 16 read/write registers listed below: </p> <table><tbody><tr><th>Register</th><th>Hexadecimal</th><th>Bit 7</th><th>Bit 6</th><th>Bit 5</th><th>Bit 4</th><th>Bit 3</th><th>Bit 2</th><th>Bit 1</th><th>Bit 0</th></tr><tr><td>0</td><td>9000</td><td>Interlace</td><td colspan="7">Horizontal origin</td></tr><tr><td>1</td><td>9001</td><td colspan="8">Vertical origin</td></tr><tr><td>2</td><td>9002</td><td>VA9</td><td colspan="7">Number of columns</td></tr><tr><td>3</td><td>9003</td><td>R0</td><td colspan="6">Number of rows</td><td>8/16</td></tr><tr><td>4</td><td>9004</td><td colspan="8">Raster line (bits 8–1)</td></tr><tr><td>5</td><td>9005</td><td colspan="4">Video addr (bits 13–10)</td><td colspan="4">Char addr (bits 13–10)</td></tr><tr><td>6</td><td>9006</td><td colspan="7">Light pen horizontal</td><td colspan="1">1</td></tr><tr><td>7</td><td>9007</td><td colspan="8">Light pen vertical</td></tr><tr><td>8</td><td>9008</td><td colspan="8">Paddle X</td></tr><tr><td>9</td><td>9009</td><td colspan="8">Paddle Y</td></tr><tr><td>10</td><td>900A</td><td>enable</td><td colspan="7">Oscillator 1 frequency</td></tr><tr><td>11</td><td>900B</td><td>enable</td><td colspan="7">Oscillator 2 frequency</td></tr><tr><td>12</td><td>900C</td><td>enable</td><td colspan="7">Oscillator 3 frequency</td></tr><tr><td>13</td><td>900D</td><td>enable</td><td colspan="7">White noise frequency</td></tr><tr><td>14</td><td>900E</td><td colspan="4">Aux color</td><td colspan="4">Volume</td></tr><tr><td>15</td><td>900F</td><td colspan="4">Background</td><td>RV</td><td colspan="3">Border</td></tr></tbody></table> <h2 id="color-palette">Color palette</h2> <p>The full palette of sixteen colors was generated based on variations of <a href="/facts/YPbPr/re8FpvzL">YPbPr</a> signals: </p> <table><tbody><tr><th>Number — name</th><th><a href="/facts/YPbPr/re8FpvzL">Y</a></th><th><a href="/facts/YPbPr/re8FpvzL">Pb</a> (rel.)</th><th><a href="/facts/YPbPr/re8FpvzL">Pr</a> (rel.)</th></tr><tr><td>0 — black</td><td>0</td><td>0</td><td>0</td></tr><tr><td>1 — white</td><td>1</td><td>0</td><td>0</td></tr><tr><td>2 — red</td><td>0.25</td><td>−0.3826834</td><td>0.9238795</td></tr><tr><td>3 — cyan</td><td>0.75</td><td>0.3826834</td><td>−0.9238795</td></tr><tr><td>4 — purple</td><td>0.5</td><td>0.7071068</td><td>0.7071068</td></tr><tr><td>5 — green</td><td>0.5</td><td>−0.7071068</td><td>−0.7071068</td></tr><tr><td>6 — blue</td><td>0.25</td><td>1</td><td>0</td></tr><tr><td>7 — yellow</td><td>0.75</td><td>−1</td><td>0</td></tr><tr><td>8 — orange</td><td>0.5</td><td>−0.7071068</td><td>0.7071068</td></tr><tr><td>9 — light orange</td><td>0.75</td><td>−0.7071068</td><td>0.7071068</td></tr><tr><td>10 — light red</td><td>0.5</td><td>−0.3826834</td><td>0.9238795</td></tr><tr><td>11 — light cyan</td><td>1</td><td>0.3826834</td><td>−0.9238795</td></tr><tr><td>12 — light purple</td><td>0.75</td><td>0.7071068</td><td>0.7071068</td></tr><tr><td>13 — light green</td><td>0.75</td><td>−0.7071068</td><td>−0.7071068</td></tr><tr><td>14 — light blue</td><td>0.5</td><td>1</td><td>0</td></tr><tr><td>15 — light yellow</td><td>1</td><td>−1</td><td>0</td></tr></tbody></table> <p>Note: Y has 5 possible values (0, 0.25, 0.5, 0.75 and 1); Pb and Pr have 7 possible values (-0.9238795, −0.7071068, −0.3826834, 0, 0.3826834, 0.7071068, 0.9238795) </p> <h2 id="vic-ic-list">VIC IC list</h2> <ul><li>MOS Technology 6560 <a href="/facts/NTSC/HYWIvxCR">NTSC</a></li> <li>MOS Technology 6561E <a href="/facts/PAL/t8TugcxK">PAL</a> Ceramic version, used in early VIC-20's</li> <li>MOS Technology 6561-101 <a href="/facts/PAL/t8TugcxK">PAL</a></li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Video_Display_Controller/ISm9E6Nc">Video Display Controller</a></li> <li><a href="/facts/Motorola_6847/4NlpBfRN">Motorola 6847</a></li> <li><a href="/facts/List_of_home_computers_by_video_hardware/z3UBNAsS">List of home computers by video hardware</a></li> <li><a href="/facts/VIC-II/3jLPsDD5">MOS VIC-II</a> as used in the <a href="/facts/Commodore_64/3TPcKDbb">Commodore 64</a></li></ul> <ul><li>Bagnall, Brian (2005). <i>On The Edge: The Spectacular Rise and Fall of Commodore</i>. Variant Press. <a href="/facts/ISBN_(identifier)/15AdSPa9">ISBN</a> 0-9738649-0-7.</li></ul> Specific <h2 id="external-links">External links</h2> <ul><li><a href="https://raw.githubusercontent.com/cbmeeks/VIC-20/master/6561.txt">VIC Chip info from Rick Melick's VIC-20 Tribute Page</a></li> <li><a href="http://www.zimmers.net/anonftp/pub/cbm/documents/chipdata/6560.zip">MOS VIC datasheet (GIF format, zipped)</a></li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>From ftp://www.zimmers.net/pub/cbm/documents/chipdata/VIC-I.txt <a href="ftp://www.zimmers.net/pub/cbm/documents/chipdata/VIC-I.txt" target="_blank">ftp://www.zimmers.net/pub/cbm/documents/chipdata/VIC-I.txt</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> </ol>