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Example for controlling a chain of WS2812 LEDs using ESP32 RMT peripheral

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This commit is contained in:
Victor Benso 2023-07-25 22:12:13 -03:00 committed by Alan Carvalho de Assis
parent c08feedcfd
commit 52ec336c55
4 changed files with 357 additions and 0 deletions
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23
examples/ws2812esp32rmt/Kconfig Normal file
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#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#
config EXAMPLES_WS2812_ESP32_RMT
tristate "ws2812 Demo Program using ESP32_RMT"
depends on ESP32_RMT
default n
---help---
Enable the ws2812 demo, using ESP32 RMT peripheral to generate the pulses
if EXAMPLES_WS2812_ESP32_RMT
config EXAMPLES_WS2812_ESP32_RMT_PRIORITY
int "Task Priority"
default 100
config EXAMPLES_WS2812_ESP32_RMT_STACKSIZE
int "Stack Size"
default DEFAULT_TASK_STACKSIZE
endif

23
examples/ws2812esp32rmt/Make.defs Normal file
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############################################################################
# apps/examples/ws2812/Make.defs
#
# 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.
#
############################################################################
ifneq ($(CONFIG_EXAMPLES_WS2812_ESP32_RMT),)
CONFIGURED_APPS += $(APPDIR)/examples/ws2812esp32rmt
endif

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examples/ws2812esp32rmt/Makefile Normal file
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############################################################################
# apps/examples/ws2812/Makefile
#
# 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.
#
############################################################################
include $(APPDIR)/Make.defs
# MTD R/W buffer test Example
PROGNAME = ws2812esp32rmt
PRIORITY = $(CONFIG_EXAMPLES_WS2812_ESP32_RMT_PRIORITY)
STACKSIZE = $(CONFIG_EXAMPLES_WS2812_ESP32_RMT_STACKSIZE)
MODULE = $(CONFIG_EXAMPLES_WS2812_ESP32_RMT)
MAINSRC = ws2812esp32rmt_main.c
include $(APPDIR)/Application.mk

279
examples/ws2812esp32rmt/ws2812esp32rmt_main.c Normal file
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/****************************************************************************
* apps/examples/ws2812esp32rmt/ws2812esp32rmt_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 <debug.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ioctl.h>
#include <unistd.h>
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define APB_PERIOD (12.5)
#define T0H ((uint16_t)(350 / APB_PERIOD)) // ns
#define T0L ((uint16_t)(900 / APB_PERIOD)) // ns
#define T1H ((uint16_t)(900 / APB_PERIOD)) // ns
#define T1L ((uint16_t)(350 / APB_PERIOD)) // ns
#define RES ((uint16_t)(60000 / APB_PERIOD)) // ns
/****************************************************************************
* Private Types
****************************************************************************/
struct led_s
{
uint8_t r;
uint8_t g;
uint8_t b;
};
/****************************************************************************
* Private Data
****************************************************************************/
static int fd;
static uint32_t *rmt_buffer;
static uint32_t rmt_buffer_len_in_words;
static uint32_t leds_buffer_len_in_bytes;
static struct led_s *leds_buffer;
/****************************************************************************
* Private Functions
****************************************************************************/
static uint32_t map_byte_to_words(uint8_t byte, uint32_t *dst)
{
uint32_t ret = 0;
uint8_t mask = 0x80;
for (int i = 0; i < 8; i++)
{
uint8_t bit = byte&mask;
mask >>= 1;
uint32_t word;
if (bit)
{
word = (T1L << 16) | (0x8000 | T1H);
}
else
{
word = (T0L << 16) | (0x8000 | T0H);
}
*dst = word;
dst++;
ret++;
}
return ret;
}
static int map_leds_to_words(struct led_s *leds,
uint32_t n_leds,
uint32_t *dst,
uint32_t dst_len_in_words
)
{
int ret = OK;
if (!dst || !leds)
{
return -1;
}
uint32_t required_words = n_leds * 3 * 8;
if (required_words >= dst_len_in_words)
{
_err("Required %d words, but buffer has only:%d",
required_words, dst_len_in_words
);
return -1;
}
uint32_t dst_offset = 0;
for (uint32_t led_idx = 0; led_idx < n_leds; led_idx++)
{
dst_offset += map_byte_to_words(leds[led_idx].g, dst + dst_offset);
dst_offset += map_byte_to_words(leds[led_idx].r, dst + dst_offset);
dst_offset += map_byte_to_words(leds[led_idx].b, dst + dst_offset);
}
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* ws2812esp32rmt_main
****************************************************************************/
int main(int argc, FAR char *argv[])
{
if (argc < 2)
{
printf("usage: %s channel led_count\n", argv[0]);
exit(1);
}
int ch_idx = atoi(argv[1]);
if (ch_idx >= 8)
{
printf("channel must be int the range 0~7\n");
exit(1);
}
uint32_t n_leds = atoi(argv[2]);
char dev_name[50];
snprintf(dev_name, 50, "/dev/rmt%d", ch_idx);
fd = open(dev_name, O_WRONLY);
if (fd < 0)
{
fprintf(stderr,
"ws2812esp32rmt: open %s failed: %d\n",
dev_name,
errno);
goto errout_with_dev;
}
_info("size of (struct led_s) is:%d", sizeof(struct led_s));
leds_buffer_len_in_bytes = sizeof(struct led_s)*n_leds;
leds_buffer = (struct led_s *)malloc(leds_buffer_len_in_bytes);
_info("leds:%d - leds_buffer %p len:%d\n",
n_leds,
leds_buffer,
leds_buffer_len_in_bytes
);
if (!leds_buffer)
{
_err("failure allocating %d bytes for LED buffer",
leds_buffer_len_in_bytes
);
goto errout;
}
rmt_buffer_len_in_words = (leds_buffer_len_in_bytes * 8 + 1);
rmt_buffer = (uint32_t *)malloc(rmt_buffer_len_in_words * 4);
_info("words:%d - rmt_buffer %p rmt_buffer_len_in_words:%d\n",
rmt_buffer_len_in_words,
rmt_buffer,
rmt_buffer_len_in_words
);
if (!rmt_buffer)
{
_err("failure allocating %d words for RMT word buffer",
rmt_buffer_len_in_words
);
goto errout;
}
int pos = 0;
int direction = 0;
/* Run the display loop */
while (1)
{
int n_loops = 30;
for (int i = 0; i < n_loops; ++i)
{
for (int l = 0; l < n_leds; l++)
{
if (!direction)
leds_buffer[l].r = i;
else
leds_buffer[l].r = 30 - i;
leds_buffer[l].g = 0x00;
leds_buffer[l].b = 0x00;
if (l == pos)
{
leds_buffer[l].r = 0x00;
leds_buffer[l].g = 0xff;
leds_buffer[l].b = 0x00;
}
}
if (pos++ >= n_leds)
pos = 0;
int ret;
ret = map_leds_to_words(leds_buffer,
n_leds,
rmt_buffer,
rmt_buffer_len_in_words
);
if (ret)
{
_err("error mapping leds to words");
goto errout;
}
ret = write(fd, rmt_buffer, rmt_buffer_len_in_words * 4);
if (ret < 0)
{
_err("error writing to device, %d errno:%d", ret, errno);
goto errout_with_dev;
}
/****************************************************************************
* Must sleep so the WS2812 can understand the EOT
****************************************************************************/
usleep(50000);
}
direction = !direction;
}
free(leds_buffer);
free(rmt_buffer);
close(fd);
fflush(stdout);
return OK;
errout_with_dev:
close(fd);
errout:
fflush(stdout);
return ERROR;
}