テンポとCTC値の関係
テンポと割り込み周期は下記の式で求められます。
周期 = 937500 / ( BPM * ( TimeBase / 4 ) )
割り込み周期の値そのものは16ビットになりますが、これを8ビットのCTC×2で設定しなければなりません。具体的には、
周期 = CTC0 * CTC3
となります。
参考:タイムベース192の場合
BPM | 周期 | CTC0 | CTC3 |
---|---|---|---|
1 | 19531 | 253 | 77 |
2 | 9765 | 250 | 39 |
3 | 6510 | 250 | 26 |
4 | 4882 | 244 | 20 |
5 | 3906 | 244 | 16 |
6 | 3255 | 250 | 13 |
7 | 2790 | 253 | 11 |
8 | 2441 | 244 | 10 |
9 | 2170 | 241 | 9 |
10 | 1953 | 244 | 8 |
11 | 1775 | 253 | 7 |
12 | 1627 | 232 | 7 |
13 | 1502 | 250 | 6 |
14 | 1395 | 232 | 6 |
15 | 1302 | 217 | 6 |
16 | 1220 | 244 | 5 |
17 | 1148 | 229 | 5 |
18 | 1085 | 217 | 5 |
19 | 1027 | 205 | 5 |
20 | 976 | 244 | 4 |
21 | 930 | 232 | 4 |
22 | 887 | 221 | 4 |
23 | 849 | 212 | 4 |
24 | 813 | 203 | 4 |
25 | 781 | 195 | 4 |
26 | 751 | 250 | 3 |
27 | 723 | 241 | 3 |
28 | 697 | 232 | 3 |
29 | 673 | 224 | 3 |
30 | 651 | 217 | 3 |
31 | 630 | 210 | 3 |
32 | 610 | 203 | 3 |
33 | 591 | 197 | 3 |
34 | 574 | 191 | 3 |
35 | 558 | 186 | 3 |
36 | 542 | 180 | 3 |
37 | 527 | 175 | 3 |
38 | 513 | 171 | 3 |
39 | 500 | 250 | 2 |
40 | 488 | 244 | 2 |
41 | 476 | 238 | 2 |
42 | 465 | 232 | 2 |
43 | 454 | 227 | 2 |
44 | 443 | 221 | 2 |
45 | 434 | 217 | 2 |
46 | 424 | 212 | 2 |
47 | 415 | 207 | 2 |
48 | 406 | 203 | 2 |
49 | 398 | 199 | 2 |
50 | 390 | 195 | 2 |
51 | 382 | 191 | 2 |
52 | 375 | 187 | 2 |
53 | 368 | 184 | 2 |
54 | 361 | 180 | 2 |
55 | 355 | 177 | 2 |
56 | 348 | 174 | 2 |
57 | 342 | 171 | 2 |
58 | 336 | 168 | 2 |
59 | 331 | 165 | 2 |
60 | 325 | 162 | 2 |
61 | 320 | 160 | 2 |
62 | 315 | 157 | 2 |
63 | 310 | 155 | 2 |
64 | 305 | 152 | 2 |
65 | 300 | 150 | 2 |
66 | 295 | 147 | 2 |
67 | 291 | 145 | 2 |
68 | 287 | 143 | 2 |
69 | 283 | 141 | 2 |
70 | 279 | 139 | 2 |
71 | 275 | 137 | 2 |
72 | 271 | 135 | 2 |
73 | 267 | 133 | 2 |
74 | 263 | 131 | 2 |
75 | 260 | 130 | 2 |
76 | 256 | 128 | 2 |
77 | 253 | 253 | 1 |
78 | 250 | 250 | 1 |
79 | 247 | 247 | 1 |
80 | 244 | 244 | 1 |
81 | 241 | 241 | 1 |
82 | 238 | 238 | 1 |
83 | 235 | 235 | 1 |
84 | 232 | 232 | 1 |
85 | 229 | 229 | 1 |
86 | 227 | 227 | 1 |
87 | 224 | 224 | 1 |
88 | 221 | 221 | 1 |
89 | 219 | 219 | 1 |
90 | 217 | 217 | 1 |
91 | 214 | 214 | 1 |
92 | 212 | 212 | 1 |
93 | 210 | 210 | 1 |
94 | 207 | 207 | 1 |
95 | 205 | 205 | 1 |
96 | 203 | 203 | 1 |
97 | 201 | 201 | 1 |
98 | 199 | 199 | 1 |
99 | 197 | 197 | 1 |
100 | 195 | 195 | 1 |
101 | 193 | 193 | 1 |
102 | 191 | 191 | 1 |
103 | 189 | 189 | 1 |
104 | 187 | 187 | 1 |
105 | 186 | 186 | 1 |
106 | 184 | 184 | 1 |
107 | 182 | 182 | 1 |
108 | 180 | 180 | 1 |
109 | 179 | 179 | 1 |
110 | 177 | 177 | 1 |
111 | 175 | 175 | 1 |
112 | 174 | 174 | 1 |
113 | 172 | 172 | 1 |
114 | 171 | 171 | 1 |
115 | 169 | 169 | 1 |
116 | 168 | 168 | 1 |
117 | 166 | 166 | 1 |
118 | 165 | 165 | 1 |
119 | 164 | 164 | 1 |
120 | 162 | 162 | 1 |
121 | 161 | 161 | 1 |
122 | 160 | 160 | 1 |
123 | 158 | 158 | 1 |
124 | 157 | 157 | 1 |
125 | 156 | 156 | 1 |
126 | 155 | 155 | 1 |
127 | 153 | 153 | 1 |
128 | 152 | 152 | 1 |
129 | 151 | 151 | 1 |
130 | 150 | 150 | 1 |
131 | 149 | 149 | 1 |
132 | 147 | 147 | 1 |
133 | 146 | 146 | 1 |
134 | 145 | 145 | 1 |
135 | 144 | 144 | 1 |
136 | 143 | 143 | 1 |
137 | 142 | 142 | 1 |
138 | 141 | 141 | 1 |
139 | 140 | 140 | 1 |
140 | 139 | 139 | 1 |
141 | 138 | 138 | 1 |
142 | 137 | 137 | 1 |
143 | 136 | 136 | 1 |
144 | 135 | 135 | 1 |
145 | 134 | 134 | 1 |
146 | 133 | 133 | 1 |
147 | 132 | 132 | 1 |
148 | 131 | 131 | 1 |
149 | 131 | 131 | 1 |
150 | 130 | 130 | 1 |
151 | 129 | 129 | 1 |
152 | 128 | 128 | 1 |
153 | 127 | 127 | 1 |
154 | 126 | 126 | 1 |
155 | 126 | 126 | 1 |
156 | 125 | 125 | 1 |
157 | 124 | 124 | 1 |
158 | 123 | 123 | 1 |
159 | 122 | 122 | 1 |
160 | 122 | 122 | 1 |
161 | 121 | 121 | 1 |
162 | 120 | 120 | 1 |
163 | 119 | 119 | 1 |
164 | 119 | 119 | 1 |
165 | 118 | 118 | 1 |
166 | 117 | 117 | 1 |
167 | 116 | 116 | 1 |
168 | 116 | 116 | 1 |
169 | 115 | 115 | 1 |
170 | 114 | 114 | 1 |
171 | 114 | 114 | 1 |
172 | 113 | 113 | 1 |
173 | 112 | 112 | 1 |
174 | 112 | 112 | 1 |
175 | 111 | 111 | 1 |
176 | 110 | 110 | 1 |
177 | 110 | 110 | 1 |
178 | 109 | 109 | 1 |
179 | 109 | 109 | 1 |
180 | 108 | 108 | 1 |
181 | 107 | 107 | 1 |
182 | 107 | 107 | 1 |
183 | 106 | 106 | 1 |
184 | 106 | 106 | 1 |
185 | 105 | 105 | 1 |
186 | 105 | 105 | 1 |
187 | 104 | 104 | 1 |
188 | 103 | 103 | 1 |
189 | 103 | 103 | 1 |
190 | 102 | 102 | 1 |
191 | 102 | 102 | 1 |
192 | 101 | 101 | 1 |
193 | 101 | 101 | 1 |
194 | 100 | 100 | 1 |
195 | 100 | 100 | 1 |
196 | 99 | 99 | 1 |
197 | 99 | 99 | 1 |
198 | 98 | 98 | 1 |
199 | 98 | 98 | 1 |
200 | 97 | 97 | 1 |
201 | 97 | 97 | 1 |
202 | 96 | 96 | 1 |
203 | 96 | 96 | 1 |
204 | 95 | 95 | 1 |
205 | 95 | 95 | 1 |
206 | 94 | 94 | 1 |
207 | 94 | 94 | 1 |
208 | 93 | 93 | 1 |
209 | 93 | 93 | 1 |
210 | 93 | 93 | 1 |
211 | 92 | 92 | 1 |
212 | 92 | 92 | 1 |
213 | 91 | 91 | 1 |
214 | 91 | 91 | 1 |
215 | 90 | 90 | 1 |
216 | 90 | 90 | 1 |
217 | 90 | 90 | 1 |
218 | 89 | 89 | 1 |
219 | 89 | 89 | 1 |
220 | 88 | 88 | 1 |
221 | 88 | 88 | 1 |
222 | 87 | 87 | 1 |
223 | 87 | 87 | 1 |
224 | 87 | 87 | 1 |
225 | 86 | 86 | 1 |
226 | 86 | 86 | 1 |
227 | 86 | 86 | 1 |
228 | 85 | 85 | 1 |
229 | 85 | 85 | 1 |
230 | 84 | 84 | 1 |
231 | 84 | 84 | 1 |
232 | 84 | 84 | 1 |
233 | 83 | 83 | 1 |
234 | 83 | 83 | 1 |
235 | 83 | 83 | 1 |
236 | 82 | 82 | 1 |
237 | 82 | 82 | 1 |
238 | 82 | 82 | 1 |
239 | 81 | 81 | 1 |
240 | 81 | 81 | 1 |
241 | 81 | 81 | 1 |
242 | 80 | 80 | 1 |
243 | 80 | 80 | 1 |
244 | 80 | 80 | 1 |
245 | 79 | 79 | 1 |
246 | 79 | 79 | 1 |
247 | 79 | 79 | 1 |
248 | 78 | 78 | 1 |
249 | 78 | 78 | 1 |
250 | 78 | 78 | 1 |
251 | 77 | 77 | 1 |
252 | 77 | 77 | 1 |
253 | 77 | 77 | 1 |
254 | 76 | 76 | 1 |
255 | 76 | 76 | 1 |