Name:
calibfreq
Syntax:

CALIBFREQ {-} factor

factor - is a constant/variable containing the value -31 to 31

Description:

Calibrate the microcontrollers internal resonator. 0 is the default factory setting.

PICAXE chips have an internal resonator that can be set to different operating speeds via the setfreq command. On these chips it is also possible to 'calibrate' this frequency. This is an advanced feature not normally required by most users, as all chips are factory calibrated to the most accurate setting.

Generally the only use for calibfreq is to slightly adjust the frequency for serial transactions with third party devices. A larger positive value increases speed, a larger negative value decreases speed. Try the values -4 to + 4 first, before going to a higher or lower value.

Use this command with extreme care. It can alter the frequency of the PICAXE chip beyond the serial download tolerance - in this case you will need to perform a hard-reset in order to carry out a new download. The calibfreq is actually a pseudo command that performs a poke command on the microcontrollers OSCTUNE register.

 

When the value is 0 to 31 the equivalent BASIC code is

  pokesfr OSCTUNE, factor
  pause 2

When the factor is -31 to -1 the equivalent BASIC code is

  let b12 = 64 - factor
  pokesfr OSCTUNE, b12
  pause 2

Note that in this case variable b12 is used, and hence corrupted, by the command. This is necessary to pokesfr the OSCTUNE register with the correct value.

Applies To:
All (except 08, 18, 18A, 28, 28A, 28X, 40X)
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Increase the speed of the internal resonator slightly

This shows how to increase the speed of the internal resonator slightly

Code Example:
	calibfreq 2
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Decrease the speed of the internal resonator slightly

This shows how to decrease the speed of the internal resonator slightly

Code Example:
	calibfreq -2
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