hdw-led.h File Reference

Detailed Description

Design Philosophy

LED code is based on Espressif's RMT Transmit Example - LED Strip.

Each LED has a red, green, and blue component. Each component ranges from 0 to 255.

LED brightness is not linear, so differences in brightness are more noticeable between small values (like 1 and 10) than between large values (like 240 and 250).

The number of LEDs are configurable by "idf.py menuconfig" and is accessible in code with the CONFIG_NUM_LEDS macro.

Usage

You don't need to call initLeds() or deinitLeds(). The system does so at the appropriate time.

You should call setLeds() any time you want to set the LEDs. There is no buffer, so the LEDs are immediately set to the values given. setLeds() takes a pointer to an array of led_t as an argument. These structs each have a red, green, and blue field.

setLedBrightness() may be called to adjust overall LED brightness. Brightness is adjusted per-color-channel, so dimming may produce different colors. setLedBrightnessSetting() should be called instead if the brightness change should be persistent through reboots.

flushLeds() may be called to wait until all pending LED transactions are completed. This does not need to be called under normal operation. The RMT peripheral handles updating LEDs in the background automatically, but transactions must be flushed before entering light sleep. If they are not, garbage data may be sent after light sleep begins, resulting in indeterminate LED behavior.

Example

Set the LEDs to a rough rainbow:

led_t leds[CONFIG_NUM_LEDS] = {0};
for (uint8_t i = 0; i < CONFIG_NUM_LEDS; i++)
{
    leds[i].r = (255 * ((i + 0) % CONFIG_NUM_LEDS)) / (CONFIG_NUM_LEDS - 1);
    leds[i].g = (255 * ((i + 3) % CONFIG_NUM_LEDS)) / (CONFIG_NUM_LEDS - 1);
    leds[i].b = (255 * ((i + 6) % CONFIG_NUM_LEDS)) / (CONFIG_NUM_LEDS - 1);
}
setLeds(leds, CONFIG_NUM_LEDS);

Go to the source code of this file.

Data Structures
struct	led_t
	LED colors, with red, green, and blue components. More...

Macros
#define	MAX_LED_BRIGHTNESS   8
	The maximum LED brightness setting.

Functions
esp_err_t	initLeds (gpio_num_t gpio, gpio_num_t gpioAlt, uint8_t brightness)
	Initialize the RGB LEDs.
esp_err_t	deinitLeds (void)
	Deinitialize LEDs.
esp_err_t	setLeds (led_t *leds, uint8_t numLeds)
	Set the RGB LEDs to the given values.
void	setLedBrightness (uint8_t brightness)
	Set the global LED brightness. setLedBrightnessSetting() should be called instead if the new volume should be persistent through a reboot.
uint8_t	getLedState (led_t *leds, uint8_t numLeds)
	Write the current LED state into the given array.
void	flushLeds (void)
	Wait until any pending LED transactions are finished, then return.

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Data Structure Documentation

led_t

struct led_t

Data Fields
uint8_t	g	The green component, 0-255.
uint8_t	r	The red component, 0-255.
uint8_t	b	The blue component, 0-255.

Macro Definition Documentation

MAX_LED_BRIGHTNESS

#define MAX_LED_BRIGHTNESS   8

The maximum LED brightness setting.

Function Documentation

initLeds()

esp_err_t initLeds	(	gpio_num_t	gpio,
		gpio_num_t	gpioAlt,
		uint8_t	brightness )

Initialize the RGB LEDs.

Parameters

gpio	The GPIO the LEDs are attached to
gpioAlt	A GPIO to mirror the LED output to
brightness	The brightness to start the LEDs at

Returns

ESP_OK if the LEDs initialized, or a nonzero value if they did not

deinitLeds()

esp_err_t deinitLeds

(

void

)

Deinitialize LEDs.

Returns

ESP_OK

setLeds()

esp_err_t setLeds	(	led_t *	leds,
		uint8_t	numLeds )

Set the RGB LEDs to the given values.

Parameters

leds	A pointer to an array of led_t structs to set the LEDs to. The array must have at least numLeds elements
numLeds	The number of LEDs to set, probably CONFIG_NUM_LEDS

Returns

ESP_OK if the LEDs were set, or a nonzero value if they did were not

setLedBrightness()

void setLedBrightness

(

uint8_t

brightness

)

Set the global LED brightness. setLedBrightnessSetting() should be called instead if the new volume should be persistent through a reboot.

Parameters

brightness

0 (off) to MAX_LED_BRIGHTNESS (max bright)

getLedState()

uint8_t getLedState	(	led_t *	leds,
		uint8_t	numLeds )

Write the current LED state into the given array.

Parameters

[out]	leds	The LED array to write the state into
	numLeds	The maximum number of LEDs to write

Returns

uint8_t The number of LEDs actually written to the array

flushLeds()

void flushLeds

(

void

)

Wait until any pending LED transactions are finished, then return.