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@ -1392,20 +1392,38 @@ supplied is beyond driver capabilities, register A will be set to $FF. |
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| _Entry Parameters_ |
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| B: 0x53 |
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| C: Audio Device Unit ID |
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| L: Note (0 to 255 quarter notes) |
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| HL: Value of note to play |
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| _Returned Values_ |
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| A: Status (0=OK, else error) |
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This function sets the sound chip period parameter according to |
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standardized notes. |
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The value corresponds to standard musical notes. The value allows |
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for selection of a quarter of a semitone by giving a value between 0 |
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and up to the drivers maximum supported value. The lowest note is (0). |
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For the SN76489 chip, 0 corresponds to note A1# and the value 249 is |
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the maximum supported value, and it corresponds to note C7. |
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This function sets the sound chip period parameter with steps of quarter |
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of a semitone. The value of 0 (lowest) corresponds to B♭/A♯ in octave 0. |
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Increase by steps of 4 to select the next corresponding note. |
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Increase by steps of 48 to select the same note in next octave. |
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If the driver is able to generate the requested note, a success (0) is |
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returned, otherwise a non-zero error state will be returned. |
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The following table shows the mapping of the input value in HL |
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to the corresponding octave and note. |
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| Note | Octave 0 | Octave 1 | Octave 2 | Octave 3 | Octave 4 | Octave 5 | Octave 6 | |
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|-------|----------|----------|----------|----------|----------|----------|----------| |
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| B♭/A♯ | 0 | 48 | 96 | 144 | 192 | 240 | 288 | |
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| B | 4 | 52 | 100 | 148 | 196 | 244 | 292 | |
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| C | 8 | 56 | 104 | 152 | 200 | 248 | 296 | |
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| C♯/D♭ | 12 | 60 | 108 | 156 | 204 | 252 | 300 | |
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| D | 16 | 64 | 112 | 160 | 208 | 256 | 304 | |
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| E♭/D♯ | 20 | 68 | 116 | 164 | 212 | 260 | 308 | |
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| E | 24 | 72 | 120 | 168 | 216 | 264 | 312 | |
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| F | 28 | 76 | 124 | 172 | 220 | 268 | 316 | |
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| F♯/G♭ | 32 | 80 | 128 | 176 | 224 | 272 | 320 | |
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| G | 36 | 84 | 132 | 180 | 228 | 276 | 324 | |
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| A♭/G♯ | 40 | 88 | 136 | 184 | 232 | 280 | 328 | |
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| A | 44 | 92 | 140 | 188 | 236 | 284 | 332 | |
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### Function 0x54 -- Sound Play (SNDPLAY) |
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Dean Netherton
6 years ago