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51 lines
1.3 KiB
51 lines
1.3 KiB
\section{PWM Unit}
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The \gls{PWM} unit uses a timer/counter to generate a \gls{PWM} (pulse train) signal. There are four outputs with a common frequency and independent duty cycles. Each channel can be individually enabled or disabled. This unit is intended for applications such as light dimming, heater regulation, or the control of H-bridges.
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\subsection{PWM Configuration}
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\begin{inicode}
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[PWMDIM:pwm@12]
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# Default pulse frequency (Hz)
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frequency=1000
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# Pin mapping - 0=disabled
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# Channel1 - 1:PA6, 2:PB4, 3:PC6
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ch1_pin=1
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# Channel2 - 1:PA7, 2:PB5, 3:PC7
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ch2_pin=0
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# Channel3 - 1:PB0, 2:PC8
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ch3_pin=0
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# Channel4 - 1:PB1, 2:PC9
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ch4_pin=0
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\end{inicode}
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\subsection{PWM Commands}
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\begin{cmdlist}
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0 & \cname{SET\_FREQUENCY}
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Set the PWM frequency
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& \begin{cmdreq}
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\cfield{u32} frequency in Hz
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\end{cmdreq} \\
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1 & \cname{SET\_DUTY}
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Set the duty cycle of one or more channels
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& \begin{cmdreq}
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\item Repeat 1--4 times:
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\begin{pldlist}
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\cfield{u8} channel number 0--3
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\cfield{u16} duty cycle 0--1000
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\end{pldlist}
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\end{cmdreq} \\
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2 & \cname{STOP}
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Stop the hardware timer. Outputs enter low level.
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& \\
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3 & \cname{START}
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Start the hardware timer.
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& \\
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\end{cmdlist}
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