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NTSC Spectrum: Difference between revisions
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Add some detail for 6C011E-3 ULA, correct discovery of 5C114E ULA
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(Add some detail for 6C011E-3 ULA, correct discovery of 5C114E ULA) |
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* The contention pattern is confirmed as being the same 6,5,4,3,2,1,0,0 as on the 48K machine. | * The contention pattern is confirmed as being the same 6,5,4,3,2,1,0,0 as on the 48K machine. | ||
Many thanks to Claudio Bernet for running all the tests on his machine. Three photos are available: [http://img.photobucket.com/albums/v400/zxspectrum/SSA40755.jpg 1], [http://img.photobucket.com/albums/v400/zxspectrum/SSA40764.jpg 2], [http://img.photobucket.com/albums/v400/zxspectrum/SSA40769.jpg 3]. | Many thanks to Claudio Bernet for running all the tests on his machine, containing a 6C011E-3 ULA, dated 8501. Three photos are available: [http://img.photobucket.com/albums/v400/zxspectrum/SSA40755.jpg 1], [http://img.photobucket.com/albums/v400/zxspectrum/SSA40764.jpg 2], [http://img.photobucket.com/albums/v400/zxspectrum/SSA40769.jpg 3]. | ||
Another NTSC Spectrum has been found by | Another NTSC Spectrum has been found by in the USA, containing a 5C114E ULA, dated 8248[http://worldofspectrum.org/forums/showthread.php?p=763629]. | ||
Although the clock rate is slightly higher, any software making heavy use of the lower 16 KB of RAM will run slower on the NTSC Spectrum, since the proportion of time during which memory is contended is greater. This is a result of the NTSC Spectrum's need to render the display at a higher frame rate (60 Hz instead of 50 Hz). | Although the clock rate is slightly higher, any software making heavy use of the lower 16 KB of RAM will run slower on the NTSC Spectrum, since the proportion of time during which memory is contended is greater. This is a result of the NTSC Spectrum's need to render the display at a higher frame rate (60 Hz instead of 50 Hz). | ||