Signetics 2650 & 2636 programming/PVI audio frequency chart

Frequency table

The chart below shows the audio frequency generated by the PVI when the value n is programmed into $1FC7.

periodcycles per framefrequency A4=440Hz[1] error
n128(n+1)μsHznote/octaveideal fdiff, Hzdiff, %
0OFF
125678.133906.25B73951.0744.821.13
238452.082604.17E72637.0232.851.25
351239.061953.13B61975.5322.411.13
464031.251562.50G61661.2298.725.94
576826.041302.08E61318.5116.431.25
689622.321116.07C61108.73-7.34-0.66
7102419.53976.56B5987.7711.211.13
8115217.36868.06A5880.0011.941.36
9128015.63781.25G5783.992.740.35
10140814.20710.23F5698.46-11.77-1.68
11153613.02651.04E5659.258.211.25
12166412.02600.96D5587.33-13.63-2.32
13179211.16558.04C5554.37-3.67-0.66
14192010.42520.83C5523.252.420.46
1520489.77488.28B4493.885.601.13
1621769.19459.56A4466.166.601.42
1723048.68434.03A4440.005.971.36
1824328.22411.18G4415.304.120.99
1925607.81390.63G4392.001.370.35
2026887.44372.02F4369.99-2.03-0.55
2128167.10355.11F4349.23-5.88-1.68
2229446.79339.67
2330726.51325.52E4329.634.111.25
2432006.25312.50D4311.13-1.37-0.44
2533286.01300.48
2634565.79289.35D4293.664.311.47
2735845.58279.02C4277.18-1.84-0.66
2837125.39269.40
2938405.21260.42C4261.631.210.46
3039685.04252.02
3140964.88244.14B3246.942.801.13
3242244.73236.74
3343524.60229.78A3233.083.301.42
3444804.46223.21
3546084.34217.01A3220.002.991.36
3647364.22211.15
3748644.11205.59G3207.652.060.99
3849924.01200.32
3951203.91195.31G3196.000.690.35
4052483.81190.55
4153763.72186.01F3185.00-1.01-0.55
4255043.63181.69
4356323.55177.56
4457603.47173.61F3174.611.000.57
4558883.40169.84
4660163.32166.22E3164.81-1.41-0.86
4761443.26162.76
4862723.19159.44
4964003.13156.25D3155.56-0.69-0.44
5065283.06153.19
5166563.00150.24
5267842.95147.41D3146.83-0.58-0.39
5369122.89144.68
5470402.84142.05
5571682.79139.51C3138.59-0.92-0.66
5672962.74137.06
5774242.69134.70
5875522.65132.42
5976802.60130.21C3130.810.600.46
6078082.56128.07
6179362.52126.01
6280642.48124.01
6381922.44122.07B2123.471.401.13
6483202.40120.19
6584482.37118.37
6685762.33116.60A2116.54-0.06-0.06
6787042.30114.89
6888322.26113.22
6989602.23111.61
7090882.20110.04A2110.00-0.04-0.03
7192162.17108.51
7293442.14107.02
7394722.11105.57
7496002.08104.17G2103.83-0.34-0.32
7597282.06102.80
7698562.03101.46
7799842.00100.16
78101121.9898.89
79102401.9597.66G298.000.340.35
80103681.9396.45
81104961.9195.27
82106241.8894.13
83107521.8693.01F292.50-0.51-0.55
84108801.8491.91
85110081.8290.84
86111361.8089.80
87112641.7888.78
88113921.7687.78F287.31-0.47-0.54
89115201.7486.81
90116481.7285.85
91117761.7084.92
92119041.6884.01
93120321.6683.11
94121601.6482.24E282.410.170.21
95122881.6381.38
96124161.6180.54
97125441.5979.72
98126721.5878.91
99128001.5678.13
100129281.5577.35D277.780.430.55
101130561.5376.59
102131841.5275.85
103133121.5075.12
104134401.4974.40
105135681.4773.70D273.42-0.28-0.39
106136961.4673.01
107138241.4572.34
108139521.4371.67
109140801.4271.02
110142081.4170.38
111143361.4069.75
112144641.3869.14C269.300.160.23
113145921.3768.53
114147201.3667.93
115148481.3567.35
116149761.3466.77
117151041.3266.21
118152321.3165.65C265.41-0.24-0.37
119153601.3065.10
120154881.2964.57
121156161.2864.04
122157441.2763.52
123158721.2663.00
124160001.2562.50
125161281.2462.00
126162561.2361.52B161.740.220.36
127163841.2261.04
128165121.2160.56
129166401.2060.10
130167681.1959.64
131168961.1859.19
132170241.1758.74
133171521.1758.30A158.27-0.03-0.06
134172801.1657.87
135174081.1557.44
136175361.1457.03
137176641.1356.61
138177921.1256.21
139179201.1255.80
140180481.1155.41
141181761.1055.02A155.00-0.02-0.03
142183041.0954.63
143184321.0954.25
144185601.0853.88
145186881.0753.51
146188161.0653.15
147189441.0652.79
148190721.0552.43
149192001.0452.08G151.91-0.17-0.33
150193281.0351.74
151194561.0351.40
152195841.0251.06
153197121.0150.73
154198401.0150.40
155199681.0050.08
156200961.0049.76
157202240.9949.45
158203520.9849.14G149.00-0.14-0.28
159204800.9848.83
160206080.9748.52
161207360.9648.23
162208640.9647.93
163209920.9547.64
164211200.9547.35
165212480.9447.06
166213760.9446.78
167215040.9346.50
168216320.9246.23F146.250.020.05
169217600.9245.96
170218880.9145.69
171220160.9145.42
172221440.9045.16
173222720.9044.90
174224000.8944.64
175225280.8944.39
176226560.8844.14
177227840.8843.89
178229120.8743.65F143.650.000.01
179230400.8743.40
180231680.8643.16
181232960.8642.93
182234240.8542.69
183235520.8542.46
184236800.8442.23
185238080.8442.00
186239360.8441.78
187240640.8341.56
188241920.8341.34
189243200.8241.12E141.200.080.20
190244480.8240.90
191245760.8140.69
192247040.8140.48
193248320.8140.27
194249600.8040.06
195250880.8039.86
196252160.7939.66
197253440.7939.46
198254720.7939.26
199256000.7839.06
200257280.7838.87D138.890.020.06
201258560.7738.68
202259840.7738.49
203261120.7738.30
204262400.7638.11
205263680.7637.92
206264960.7537.74
207266240.7537.56
208267520.7537.38
209268800.7437.20
210270080.7437.03
211271360.7436.85
212272640.7336.68D136.710.030.09
213273920.7336.51
214275200.7336.34
215276480.7236.17
216277760.7236.00
217279040.7235.84
218280320.7135.67
219281600.7135.51
220282880.7135.35
221284160.7035.19
222285440.7035.03
223286720.7034.88
224288000.6934.72C134.65-0.07-0.21
225289280.6934.57
226290560.6934.42
227291840.6934.27
228293120.6834.12
229294400.6833.97
230295680.6833.82
231296960.6733.67
232298240.6733.53
233299520.6733.39
234300800.6633.24
235302080.6633.10
236303360.6632.96
237304640.6632.83
238305920.6532.69C132.700.010.04
239307200.6532.55
240308480.6532.42
241309760.6532.28
242311040.6432.15
243312320.6432.02
244313600.6431.89
245314880.6431.76
246316160.6331.63
247317440.6331.50
248318720.6331.38
249320000.6331.25
250321280.6231.13
251322560.6231.00
252323840.6230.88B030.87-0.01-0.03
253325120.6230.76
254326400.6130.64
255327680.6130.52

PVI integers and indexes chart

PVI integer (index number)
Note\Octave01234567
C  238(1)118(13)59(25)29(37)14(49)  
C/D  224(2)112(14)55(26)27(38)13(50)6(62) 
D  212(3)105(15)52(27)26(39)12(51)  
E/D  200(4)100(16)49(28)24(40)   
E  189(5)94(17)46(29)23(41)11(53)5(65)2(77)
F  178(6)88(18)44(30)21(42)10(54)  
F/G  168(7)83(19)41(31)20(43)   
G  158(8)79(20)39(32)19(44)9(56)4(68) 
A/G  149(9)74(21)37(33)18(45)   
A  141(10)70(22)35(34)17(46)8(58)  
B/A  133(11)66(23)33(35)16(47)   
B 252(0)126(12)63(24)31(36)15(48)7(60)3(72)1(84)

Coded index table

This table is just one way of implementing an index table to look up integer values corresponding to a musical note to feed to the PVI sound register $1FC7. Each unit step in index value shift by one semitone. Stepping by 12 in the index value shifts by an octave.

The lookup table uses 85 bytes and covers the range B0 to B7 but could be shrunk by reducing the range, or by eliminating notes not used in the composition. Note that beyond D5 many notes are not available.

PitchLUT:
; Octave 0
            db 252   ; 0   B
; Octave 1
            db 238   ; 1   C
            db 224   ; 2   C♯ / D♭
            db 212   ; 3   D
            db 200   ; 4   D♯ / E♭
            db 189   ; 5   E
            db 178   ; 6   F
            db 168   ; 7   F♯ / G♭
            db 158   ; 8   G
            db 149   ; 9   G♯ / A♭
            db 141   ; 10  A
            db 133   ; 11  A♯ / B♭
            db 126   ; 12  B
; Octave 2
            db 118   ; 13  C
            db 112   ; 14  C♯ / D♭
            db 105   ; 15  D
            db 100   ; 16  D♯ / E♭
            db 94    ; 17  E
            db 88    ; 18  F
            db 83    ; 19  F♯ / G♭
            db 79    ; 20  G
            db 74    ; 21  G♯ / A♭
            db 70    ; 22  A
            db 66    ; 23  A♯ / B♭
            db 63    ; 24  B
; Octave 3
            db 59    ; 25  C
            db 55    ; 26  C♯ / D♭
            db 52    ; 27  D
            db 49    ; 28  D♯ / E♭
            db 46    ; 29  E
            db 44    ; 30  F
            db 41    ; 31  F♯ / G♭
            db 39    ; 32  G
            db 37    ; 33  G♯ / A♭
            db 35    ; 34  A
            db 33    ; 35  A♯ / B♭
            db 31    ; 36  B 
; Octave 4
            db 29    ; 37  C          Middle C
            db 27    ; 38  C♯ / D♭
            db 26    ; 39  D
            db 24    ; 40  D♯ / E♭
            db 23    ; 41  E
            db 21    ; 42  F
            db 20    ; 43  F♯ / G♭
            db 19    ; 44  G
            db 18    ; 45  G♯ / A♭
            db 17    ; 46  A
            db 16    ; 47  A♯ / B♭
            db 15    ; 48  B
; Octave 5
            db 14    ; 49  C
            db 13    ; 50  C♯ / D♭
            db 12    ; 51  D
            ;............................End of contiguous semitone intervals (chromatic scales)
            ;.......................The following notes may be useful to complete other scales:
            db 0     ; 52   
            db 11    ; 53  E
            db 10    ; 54  F
            db 0     ; 55   
            db 9     ; 56  G
            db 0     ; 57   
            db 8     ; 58  A
            db 0     ; 59   
            db 7     ; 60  B
; Octave 6
            db 0     ; 61   
            db 6     ; 62  C♯ / D♭
            db 0     ; 63   
            db 0     ; 64   
            db 5     ; 65  E
            db 0     ; 66   
            db 0     ; 67   
            db 4     ; 68  G
            db 0     ; 69   
            db 0     ; 70   
            db 0     ; 71   
            db 3     ; 72  B
; Octave 7
            db 0     ; 73   
            db 0     ; 74   
            db 0     ; 75   
            db 0     ; 76   
            db 2     ; 77  E
            db 0     ; 78   
            db 0     ; 79   
            db 0     ; 80   
            db 0     ; 81   
            db 0     ; 82   
            db 0     ; 83   
            db 1     ; 84  B            

References

Category:Book:Signetics 2650 & 2636 programming#PVI%20audio%20frequency%20chart%20
Category:Book:Signetics 2650 & 2636 programming