Play Tone

Description

This command plays a tone derived from the parameter. The tone is played indefinitely until the rMP3 receives either the Play Tone command again with no parameter, or the Stop command. If a file is being played when the Play Tone command is received, playback will resume if the Play Tone command is received with no parameter.

Note: Tones are generated using the VS10xx decoder’s “Sine Test”. The range and quantization of frequencies are pretty limited. For reference, here is an entire table of frequencies.

Format

PC T [tone]

Parameters

• tone is a value between 0 and 255.
  • To calculate the tone value:
    • Tone Frequency = Base Frequency * d/128
      • This means that there can be more than one combination of Base Frequency and d for a Tone Frequency.
    • tone = Base Frequency Index + d
    • d is the divider value (1 → 31), which will give a range of divider fractions (1/128 → 31/128). A divider value of 0 will produce no sound.
    • Base Frequency Index Table:

Example, to play a 6000 Hz tone:

• Base Frequency = 48000 Hz, therefore Base Frequency Index = 32.
• d = 16.
• Tone Frequency = 48000 * 16/128 = 6000 Hz.
• tone = 32 + 16 = 48
  • PC T 48

Response Format

NULL

Example