* apps/examples/apa102/apa102_main.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <nuttx/leds/apa102.h>
* Pre-processor Definitions
****************************************************************************/
#define CONFIG_EXAMPLES_APA102_DEVNAME "/dev/leddrv0"
* Private Data
****************************************************************************/
#define NUM_LEDS 30
#define US_DELAY 1000
struct apa102_ledstrip_s ledstrip[NUM_LEDS];
* Private Functions
****************************************************************************/
* Name: hsvtorgb
*
* Description:
* Converts a color from HSV to RGB.
*
* Note: This function is based on Pololu example:
* https://github.com/pololu/apa102-arduino/blob/master/examples/Rainbow/
* Rainbow.ino
*
* Input Parameters:
* h is hue, as a number between 0 and 360.
* s is the saturation, as a number between 0 and 255.
* v is the value, as a number between 0 and 255.
*
****************************************************************************/
static struct apa102_ledstrip_s hsvtorgb(uint16_t h, uint8_t s, uint8_t v)
{
struct apa102_ledstrip_s led;
uint8_t f = (h % 60) * 255 / 60;
uint8_t p = (255 - s) * (uint16_t)v / 255;
uint8_t q = (255 - f * (uint16_t)s / 255) * (uint16_t)v / 255;
uint8_t t = (255 - (255 - f) * (uint16_t)s / 255) * (uint16_t)v / 255;
uint8_t r = 0;
uint8_t g = 0;
uint8_t b = 0;
switch ((h / 60) % 6)
{
case 0:
r = v;
g = t;
b = p;
break;
case 1:
r = q;
g = v;
b = p;
break;
case 2:
r = p;
g = v;
b = t;
break;
case 3:
r = p;
g = q;
b = v;
break;
case 4:
r = t;
g = p;
b = v;
break;
case 5:
r = v;
g = p;
b = q;
break;
}
led.red = r;
led.green = g;
led.blue = b;
led.bright = 0;
return led;
}
* Public Functions
****************************************************************************/
* apa102_main
****************************************************************************/
int main(int argc, FAR char *argv[])
{
int fd;
int ret;
int led;
int miles = 10000;
fd = open(CONFIG_EXAMPLES_APA102_DEVNAME, O_RDWR);
if (fd < 0)
{
fprintf(stderr, "ERROR: Failed to open %s: %d\n",
CONFIG_EXAMPLES_APA102_DEVNAME, errno);
return -1;
}
for (; ; )
{
for (led = 0; led < NUM_LEDS; led++)
{
uint8_t p = miles - led * 8;
ledstrip[led] = hsvtorgb((uint32_t)p * 359 / 256, 255, 255);
}
ret = write(fd, ledstrip, 4 * NUM_LEDS);
if (ret < 0)
{
_err("ERROR: write LED Strip failed: %d\n", errno);
}
usleep(US_DELAY);
miles += (US_DELAY / 1000);
}
close(fd);
return 0;
}