====== Pwm ======

''Pwm channel, duty, period''
| //channel// |PWM channel (0 to 15)   |
| //duty// | Duty cycle (must be less than the period)    |
| //period// | Maximum of 65535    |

Outputs a pulse waveform whose shape is determined by the values of duty
and period. Be aware that the PWM channel is different from the I/O port
number. For the CB280, ports 5, 6, and 7 are used for PWM 0, 1, and 2.
Before using ''Pwm'', make sure to set the ports' I/O mode to output, and set
their output to a known state (logic low or logic high).

Depending on the value of period, a PWM signal of up to 16 bit precision is
generated. A period of 1024 is a 10 bit pulse and a period of 65535 is a 16
bit pulse. The pulse's actual frequency in Hz can be computed with the
following formula.

                   Frequency = 2,304,000 / period                                     
//duty// must to be less than //period//. The pulse's output will remain active for
a fraction of the period given by //duty/////period//.
''Pwm'' is independently hardware driven within the Cubloc. Once the ''Pwm''
command is executed, it will keep running until the ''PwmOff'' command is
called.
 
{{ :cubloc:pwm:pwm.png?nolink |}}


<code xbasic>
Low 5              ' Set port 5 output and output LOW signal.
Pwm 0,200,1024     ' Output 10-bit pulse with duty of 200 and width of 1024

</code>

===== IMPORTANT =====
PWM channels 0, 1, and 2 must use the same value for period
since they share the same resources, but their duty cycles can
be different. PWM channels 3, 4, and 5 also must use the same
value for period, but again, their duty cycles can be different.

===== PWM ports =====
The following illustrates the PWM channels available on each module:

{{ :cubloc:pwm:cb220pwm.png?nolink |}}

For CB220, 3 PWM channels are provided on ports P5, P6, and P7.

{{ :cubloc:pwm:cb280pwm.png?nolink |}}

Please refer to the table below for PWM channels and their corresponding I/O ports.

^  ^ CB220  ^ CB280  ^ CB290   ^ CT17XX  ^ CB400 \\ CB405 \\ CB405RT  |       
| PWM0   | I/O 5  | I/O 5   | I/O 5   | I/O 8                | I/O 5   |
| PWM1   | I/O 6  | I/O 6   | I/O 6   | I/O 9                | I/O 6   |
| PWM2   | I/O 7  | I/O 7   | I/O 7   | I/O 10               | I/O 7   |
| PWM3   |        | I/O 19  | I/O 89  | I/O 11               | I/O 27  |
| PWM4   |        | I/O 20  | I/O 90  | I/O 12               | I/O 28  |
| PWM5   |        | I/O 21  | I/O 91  | I/O 13               | I/O 29  |
| PWM6   |        |         |         |                      | I/O 11  |
| PWM7   |        |         |         |                      | I/O 12  |
| PWM8   |        |         |         |                      | I/O 13  |
| PWM9   |        |         |         |                      | I/O 51  |
| PWM10  |        |         |         |                      | I/O 52  |
| PWM11  |        |         |         |                      | I/O 53  |

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