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