63 lines
1.9 KiB
YAML
63 lines
1.9 KiB
YAML
description: nRFx S/W PWM
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compatible: "nordic,nrf-sw-pwm"
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include: [pwm-controller.yaml, base.yaml]
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properties:
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generator:
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type: phandle
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required: true
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description: |
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Reference to TIMER or RTC instance for generating PWM output signals
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clock-prescaler:
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type: int
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required: true
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description: |
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Clock prescaler for RTC or TIMER used for generating PWM output signals.
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RTC: needs to be set to 0, which gives 32768 Hz base clock for PWM
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generation.
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TIMER: 16 MHz / 2^prescaler base clock is used for PWM generation.
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channel-gpios:
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type: phandle-array
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required: true
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description: |
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An array of GPIOs assigned as outputs for the PWM channels. The number
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of items in this array determines the number of channels that this PWM
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will provide. This value is limited by the number of compare registers
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in the used RTC/TIMER instance minus 1.
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Example:
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sw_pwm: sw-pwm {
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compatible = "nordic,nrf-sw-pwm";
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...
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channel-gpios = <&gpio0 20 GPIO_ACTIVE_HIGH>,
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<&gpio1 12 GPIO_ACTIVE_HIGH>;
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...
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};
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The above will assign P0.20 as the output for channel 0 and P1.12 as
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the output for channel 1. Both outputs will be initially configured as
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active high.
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Please note that in the flags cell (the last component of each item
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of the array) only the GPIO flags that specify the active level are
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taken into account (any others are ignored), and they are used only
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when the initial (inactive) state of the outputs is set.
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After any PWM signal generation is requested for a given channel,
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the polarity of its output is determined by the flag specified
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in the request, i.e. PWM_POLARITY_INVERTED or PWM_POLARITY_NORMAL.
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"#pwm-cells":
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const: 3
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pwm-cells:
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- channel
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- period
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- flags
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