FreqOut channel, freqValue
channel | PWM channel (0 to 15) |
freqValue | Frequency value between 1 and 65535 |
FreqOut output the specified frequency to the specified PWM channel. Please make sure to specify the PWM channel, not the I/O port number. For the CB220 and CB280, ports 5, 6, and 7 correspond to PWM Channel 0, 1, and 2, respectively.
The following chart shows several example freqValues and their corresponding frequencies. The highest possible frequency can be achieved by setting freqValue to 1 and the lowest possible can be achieved by setting freqValue to 65535. A freqValue of 0 does not produce any output.
FreqValue | Frequency |
---|---|
1 | 1152 KHz |
2 | 768 kHz |
3 | 576 KHz |
4 | 460.8KHz |
5 | 384 KHz |
10 | 209.3 KHz |
20 | 109.7 KHz |
30 | 74.4 KHz |
100 | 22.83 KHz |
200 | 11.52 KHz |
1000 | 2.3 KHz |
2000 | 1.15 KHz |
3000 | 768 Hz |
4000 | 576 Hz |
10000 | 230 Hz |
20000 | 115.2 Hz |
30000 | 76.8 Hz |
65535 | 35.16 Hz |
You can calculate freqValue using the following formula:
freqValue = 2,304,000 / Desired Frequency
Before using this command, please set the specified PWM port to output mode and set to a logic high or logic low state. To stop the output, use the PWMOff command.
The following is an example:
Const Device = CB280 Dim i As Integer Low 5 ' Set Port 5 to low and output. i = 1 FreqOut 0,10 ' Produce a 209.3Khz wave Do ' Infinite loop Loop
Since FreqOut uses the same resources as the PWM, there are some restrictions to consider. PWM channels 0, 1, and 2 use the same timer.
If PWM channel 0 is used for a FreqOut command, PWM channels 0, 1, and 2 cannot be used for a PWM command.
Likewise, PWM Channels 3, 4, and 5 are linked. If FreqOut is used on PWM channel 3, PWM Channels 3, 4, and 5 cannot be used for a PWM command.
You can produce different frequencies on PWM channels 0 and 3.
To summarize, two different frequencies can be produced at one time, and when using the FreqOut command, a PWM command cannot be used on the same channel.
The following is a chart that correlates freqValue to musical notes:
Note | Octave 2 | Octave 3 | Octave 4 | Octave 5 |
---|---|---|---|---|
A | 20945 | 10473 | 5236 | 2618 |
Bb | 19770 | 9885 | 4942 | 2471 |
B | 18660 | 9330 | 4665 | 2333 |
C | 17613 | 8806 | 4403 | 2202 |
Db | 16624 | 8312 | 4156 | 2078 |
D | 15691 | 7846 | 3923 | 1961 |
Eb | 14811 | 7405 | 3703 | 1851 |
E | 13979 | 6990 | 3495 | 1747 |
F | 13195 | 6597 | 3299 | 1649 |
Gb | 12454 | 6227 | 3114 | 1557 |
G | 11755 | 5878 | 2939 | 1469 |
Ab | 11095 | 5548 | 2774 | 1387 |
FreqOut 0,5236 ' Note A in Octave 4(440Hz) FreqOut 0,1469 ' Note G in Octave 5