ESP32 LEDC Output¶
The LEDC output component exposes a LEDC PWM channel of the ESP32 as an output component.
The frequency range of LEDC is from 10Hz to 40MHz - however, higher frequencies require a smaller bit depth which means the output is not that accurate for frequencies above ~300kHz.
Configuration variables:¶
pin (Required, Pin): The pin to use LEDC on. Can only be GPIO0-GPIO33.
id (Required, ID): The id to use for this output component.
frequency (Optional, float): At which frequency to run the LEDC channel’s timer. Defaults to 1000Hz.
All other options from Output.
Advanced options:
channel (Optional, int): Manually set the LEDC channel to use. Two adjacent channels share the same timer. Defaults to an automatic selection.
Note: When configuring custom frequencies for two or more outputs, ensure that you manually specify channel 0, 2, 4, 6 for each output. This will prevent issues that arise from automatic selection, which chooses adjacent channels with shared timers. See Issue #3114 for more details.
phase_angle (Optional, float): Set a phase angle to the other channel of this timer. Range 0-360°, defaults to 0°
Note: this variable is only available for the esp-idf framework
Example Usage For a Light¶
# Example configuration entry
output:
- platform: ledc
pin: GPIOXX
id: gpio_
# Example usage in a light
light:
- platform: monochromatic
output: gpio_19
name: "Kitchen Light"
Example Usage For a Piezo Buzzer¶
# Configure the output
output:
- platform: ledc
######################################################
# One buzzer leg connected to GPIO12, the other to GND
######################################################
pin: GPIO12
id: buzzer
# Example usage in an automation
on_press:
then:
######################################################
# Must be turned on before setting frequency & level
######################################################
- output.turn_on: buzzer
######################################################
# Frequency sets the wave size
######################################################
- output.ledc.set_frequency:
id: buzzer
frequency: "1000Hz"
######################################################
# level sets the %age time the PWM is on
######################################################
- output.set_level:
id: buzzer
level: "50%"
Recommended frequencies¶
To get the highest available frequency while still getting the same bit depth it is recommended to pick one of the following frequencies.
Higher bit depth means that the light has more steps available to change from one value to another. This is especially noticeable when the light is below 10% and takes a long transition, e.g. turning slowly off.
Frequency |
Bit depth |
Available steps for transitions |
1220Hz |
16 |
65536 |
2441Hz |
15 |
32768 |
4882Hz |
14 |
16384 |
9765Hz |
13 |
8192 |
19531Hz |
12 |
4096 |
The ESP8266 for instance has usually a frequency of 1000Hz with a resolution of 10 bits. This means that there are only 4 steps between each value.
output.ledc.set_frequency Action¶
This Action allows you to manually change the frequency of an LEDC channel at runtime. Use cases include controlling a passive buzzer (for pitch control).
on_...:
- output.ledc.set_frequency:
id: ledc_output
frequency: 100Hz
Configuration variables:
id (Required, ID): The ID of the LEDC output to change.
frequency (Required, templatable, float): The frequency to set in hertz.