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AY-3-8912: Difference between revisions
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[[Category:Hardware]] | [[Category:Hardware]] | ||
[[Category:Audio]] | [[Category:Audio]] | ||
The '''AY-3-8912''' is a sound generator that is built-in on the [[ZX Spectrum 128K models]] and in the [[Timex 2000 series|Timex Sinclair 2068]], but can also be found in several peripherals, such as the Fuller Box | The '''AY-3-8912''' is a sound generator that is built-in on the [[ZX Spectrum 128K models]] and in the [[Timex 2000 series|Timex Sinclair 2068]], but can also be found in several peripherals, such as the Fuller Box and the Melodik interface. On the 128K models it also provides external I/O connections. | ||
On [[ZX Spectrum 128K models]] the AY chip is clocked at 1.7734 MHz (to within 0.01%). Writing to port FFFDh (65533) selects a register, and reading from port FFFDh reads that register's contents. Writing to port BFFDh (49149) writes new data to the currently selected register. On the [[ZX Spectrum 128]] and [[ZX Spectrum +2]], reading from BFFDh will return the [[floating bus]] value as normal for unattached ports, but on the [[ZX Spectrum +2A/2B, +3/3B|ZX Spectrum +2A, +3, +2B, and +3B]] machines, it will return the same as reading from FFFDh. The Melodik interface uses the same ports as the Spectrum 128. | On [[ZX Spectrum 128K models]] the AY chip is clocked at 1.7734 MHz (to within 0.01%). Writing to port FFFDh (65533) selects a register, and reading from port FFFDh reads that register's contents. Writing to port BFFDh (49149) writes new data to the currently selected register. On the [[ZX Spectrum 128]] and [[ZX Spectrum +2]], reading from BFFDh will return the [[floating bus]] value as normal for unattached ports, but on the [[ZX Spectrum +2A/2B, +3/3B|ZX Spectrum +2A, +3, +2B, and +3B]] machines, it will return the same as reading from FFFDh. The Melodik interface uses the same ports as the Spectrum 128. | ||
