[Octave-bug-tracker] [bug #62538] [octave forge] (arduino) playTone function does not play the correct frequency

[Koichi Hamada]

URL:
  <https://savannah.gnu.org/bugs/?62538>

                 Summary: [octave forge] (arduino) playTone function does not
play the correct frequency
                 Project: GNU Octave
            Submitted by: hamadak2000
            Submitted on: Sun 29 May 2022 01:22:24 AM UTC
                Category: Octave Forge Package
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: Incorrect Result
                  Status: None
             Assigned to: None
         Originator Name: Koichi Hamada
        Originator Email: 
             Open/Closed: Open
                 Release: 6.4.0
         Discussion Lock: Any
        Operating System: Any


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Follow-up Comments:


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Date: Sun 29 May 2022 01:22:24 AM UTC By: Koichi Hamada <hamadak2000>
I found a computational bug in "playTone.m".
The bit-shift operation is incorrect at Line 64 in file "playTone.m".

63: freq = uint16(freq);
64: freqh = bitand(freq/256, hex2dec('FF'));


The bitshift() function shold be used for bit-shift operation.
This is because division over uint16 types does not return the value we
expect. 
For example, Octave returns "2" as a result of "uint16(400)/256".

So the code "freq/256" at Line 64 should be replace by "bitshift(freq, -8)".
Line 68 needs the same modification.







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