Basic Micro Studio Syntax Manual

FREQOUT
Syntax
freqout pin, duration, freq1{,freq2}
Commands
• Pin - is a variable, constant or expression that specifi es the I/O pin to be used. This pin will be set
to output mode during tone generation and then left in that state after output is completed.
• Duration - is a variable, constant or expression that specifi es the duration of the output tone in
milliseconds.
• Freq1 - is a variable, constant or expression that specifi es the frequency in Hz of the fi rst tone
which can be between 0 – 32767Hz.
• Freq2 - is an optional variable, constant or expression that specifi es the frequency in Hz of the
second tone which can be between 0 – 32767Hz.
Supported
• BA - Supported
• BAN - Supported
• BAP - Supported
• BAP40 - Supported
Description
This command generates one or two tones that are output on a single I/O pin. The signal generated is
a pulse width modulated signal. This command can be used to create music, tones or general output
signals. The maximum supported range is limited to what is practical. There aren’t many speakers or
piezo devices on the market that will work well outside of 30Khz, which is why MBasic is limited to a
maximum of 32Khz.
Notes
1. The tones are generated mathematically and output as a pulse width modulated (PWM) signal.
The signal must be converted to a sine wave (or a pair of sine waves) by passing it through an
integrator which is a low pass fi lter.
Example
The code snippet below will generate a 1000Hz tone for 5 seconds on P1.
freqout p1, 5000, 1000
The next code snippet will generate two tones 1000Hz and 2000Hz for 5 seconds on P1.
freqout p1, 5000, 1000, 2000
110