Kann man schon berechnen:
http://www.mcselec.com/index.php?option=com_content&task=view&id=221&Item id=57

Code:
' *****   FORMAT TO FUNCTIONS SOUND  *****
'
' Sound Speaker , Pulses , Periods
 ' Speaker - port for generations of sound
' Periods - sound frequency (1-65535)
' Pulses  - duration of sound (1-65535)
 '
' Periods = Abc[F_crystal / (k * F_nota)]
' Pulses  = Abc[(T_period * F_crystal) / (k * Periods)]
 '
' F_crystal - clockrate of controller, Hz
' F_nota    - frequency a notes, Hz
 ' k = 12    - amount of tacts, for which is formed one period of sound
 ' T_period  - duration of sounding a notes, sec
' Abc       - function of truncation whole number
 '
'===============================================================================
' Table of values Pulses,Periods for 3 octaves at frequency of quartz 8000000 Hz
 '===============================================================================
'Note|Freqvency|Periods|Pulses 1/1|Pulses 1/2|Pulses 1/4|Pulses 1/8|Pulses 1/16|
'===============================================================================
' C1 |  261,63 |  2548 |    523   |    262   |    131   |    65    |     33    |
 'Cis1|  277,18 |  2405 |    554   |    277   |    139   |    69    |     35    |
' D1 |  293,66 |  2270 |    587   |    294   |    147   |    73    |     37    |
 'Dis1|  311,13 |  2143 |    622   |    311   |    156   |    78    |     39    |
' E1 |  329,63 |  2022 |    659   |    330   |    165   |    82    |     41    |
 ' F1 |  349,23 |  1909 |    698   |    349   |    175   |    87    |     44    |
 'Fis1|  369,99 |  1802 |    740   |    370   |    185   |    92    |     46    |
' G1 |  392,00 |  1701 |    784   |    392   |    196   |    98    |     49    |
 'Gis1|  415,30 |  1605 |    831   |    415   |    208   |   104    |     52    |
' A1 |  440,00 |  1515 |    880   |    440   |    220   |   110    |     55    |
 'Ais1|  466,16 |  1430 |    932   |    466   |    233   |   117    |     58    |
' B1 |  493,88 |  1350 |    988   |    494   |    247   |   124    |     62    |