119 lines
3.3 KiB
YAML
119 lines
3.3 KiB
YAML
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# Copyright (c) 2022 Espressif Systems (Shanghai) Co., Ltd.
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# SPDX-License-Identifier: Apache-2.0
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description: |
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Espressif's Motor Control Pulse Width Modulator (MCPWM) controller Node
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The MCPWM peripheral is intended for motor and power control.
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It provides six PWM outputs that can be set up to operate in several topologies
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ESP32 contains two MCPWM peripherals: MCPWM0 and MCPWM1
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Each MCPWM peripheral has one clock divider (prescaler), three PWM timers, three PWM operators,
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and a capture module.
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Every PWM operator has two PWM outputs: PWMxA and PWMxB. They can work independently, in symmetric
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and asymmetric configuration. MCPWMxA and MCPWMxB will share the same timer, thus having the same
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operating frequency.
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The driver currently always use the timer x for operator x. Timer 0 will use operator 0 for PWM0A/B.
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Timer 1 will use operator 1 for PWM1A/B, and so on.
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Mapping channel ID:
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Channel 0 -> Timer 0, Operator 0, output PWM0A
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Channel 1 -> Timer 0, Operator 0, output PWM0B
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Channel 2 -> Timer 1, Operator 1, output PWM1A
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Channel 3 -> Timer 1, Operator 1, output PWM1B
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Channel 4 -> Timer 2, Operator 2, output PWM2A
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Channel 5 -> Timer 2, Operator 2, output PWM2B
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Channel 6 -> Capture 0
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Channel 7 -> Capture 1
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Channel 8 -> Capture 2
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Example: Use PWM0A output and capture 0:
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pwm_loopback_0 {
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compatible = "test-pwm-loopback";
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pwms = <&mcpwm0 0 0 PWM_POLARITY_NORMAL>, #Channel 0 -> Output PWM0A
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<&mcpwm0 6 0 PWM_POLARITY_NORMAL>; #Channel 6 -> Capture 0;
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};
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The mapping between the output PWMxA/B or CaptureX and GPIO is done through pinctrl:
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&mcpwm0 {
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pinctrl-0 = <&mcpwm0_default>;
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pinctrl-names = "default";
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}
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The 'mcpwm0_default' node is defined inside the pinctrl node.
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&pinctrl {
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mcpwm0_default: mcpwm0_default {
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group1 {
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pinmux = <MCPWM0_OUT0A_GPIO0>,
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<MCPWM0_OUT0B_GPIO2>,
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<MCPWM0_OUT1A_GPIO4>;
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output-enable;
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};
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group2 {
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pinmux = <MCPWM0_CAP0_GPIO5>;
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};
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};
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};
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Note: Check espressif,esp32-pinctrl.yaml for complete documentation regarding pinctrl.
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Use the prescale-timerX property to configure the timers:
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&mcpwm0 {
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pinctrl-0 = <&mcpwm0_default>;
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pinctrl-names = "default";
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prescale = <255>;
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prescale-timer0 = <103>;
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prescale-timer1 = <0>;
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prescale-timer2 = <255>;
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status = "okay";
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};
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compatible: "espressif,esp32-mcpwm"
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include: [pwm-controller.yaml, pinctrl-device.yaml, base.yaml]
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properties:
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prescale:
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type: int
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required: true
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description: |
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8 bit timer prescale for the global clock.
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Period of PWM_clk = 6.25ns * (PWM_CLK_PRESCALE + 1).
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"#pwm-cells":
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const: 3
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prescale-timer0:
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type: int
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required: false
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description: |
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8 bit timer prescale for timer 0.
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Period of PT0_clk = Period of PWM_clk * (PWM_TIMER0_PRESCALE + 1).
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prescale-timer1:
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type: int
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required: false
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description: |
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8 bit timer prescale for timer 1.
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Period of PT1_clk = Period of PWM_clk * (PWM_TIMER1_PRESCALE + 1).
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prescale-timer2:
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type: int
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required: false
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description: |
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8 bit timer prescale for timer 2.
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Period of PT2_clk = Period of PWM_clk * (PWM_TIMER2_PRESCALE + 1).
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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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