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light_ws2811strip.c
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light_ws2811strip.c
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/*
* This file is part of Cleanflight.
*
* Cleanflight is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Cleanflight is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Cleanflight. If not, see <http://www.gnu.org/licenses/>.
*/
/*
* "Note that the timing on the WS2812/WS2812B LEDs has changed as of batches from WorldSemi
* manufactured made in October 2013, and timing tolerance for approx 10-30% of parts is very small.
* Recommendation from WorldSemi is now: 0 = 400ns high/850ns low, and 1 = 850ns high, 400ns low"
*
* Currently the timings are 0 = 350ns high/800ns and 1 = 700ns high/650ns low.
*/
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <platform.h>
#ifdef USE_LED_STRIP
#include "build/build_config.h"
#include "common/color.h"
#include "common/colorconversion.h"
#include "drivers/dma.h"
#include "drivers/io.h"
#include "drivers/timer.h"
#include "drivers/light_ws2811strip.h"
static uint32_t ledStripDMABuffer[WS2811_DMA_BUFFER_SIZE];
static IO_t ws2811IO = IO_NONE;
static TCH_t * ws2811TCH = NULL;
static bool ws2811Initialised = false;
static uint16_t BIT_COMPARE_1 = 0;
static uint16_t BIT_COMPARE_0 = 0;
static hsvColor_t ledColorBuffer[WS2811_LED_STRIP_LENGTH];
void setLedHsv(uint16_t index, const hsvColor_t *color)
{
ledColorBuffer[index] = *color;
}
void getLedHsv(uint16_t index, hsvColor_t *color)
{
*color = ledColorBuffer[index];
}
void setLedValue(uint16_t index, const uint8_t value)
{
ledColorBuffer[index].v = value;
}
void scaleLedValue(uint16_t index, const uint8_t scalePercent)
{
ledColorBuffer[index].v = ((uint16_t)ledColorBuffer[index].v * scalePercent / 100);
}
void setStripColor(const hsvColor_t *color)
{
uint16_t index;
for (index = 0; index < WS2811_LED_STRIP_LENGTH; index++) {
setLedHsv(index, color);
}
}
void setStripColors(const hsvColor_t *colors)
{
uint16_t index;
for (index = 0; index < WS2811_LED_STRIP_LENGTH; index++) {
setLedHsv(index, colors++);
}
}
void ws2811LedStripInit(void)
{
const timerHardware_t * timHw = timerGetByTag(IO_TAG(WS2811_PIN), TIM_USE_ANY);
if (timHw == NULL) {
return;
}
ws2811TCH = timerGetTCH(timHw);
if (ws2811TCH == NULL) {
return;
}
/* Compute the prescaler value */
uint16_t period = 1000000 * WS2811_TIMER_MHZ / WS2811_CARRIER_HZ;
BIT_COMPARE_1 = period / 3 * 2;
BIT_COMPARE_0 = period / 3;
ws2811IO = IOGetByTag(IO_TAG(WS2811_PIN));
IOInit(ws2811IO, OWNER_LED_STRIP, RESOURCE_OUTPUT, 0);
IOConfigGPIOAF(ws2811IO, IOCFG_AF_PP_FAST, timHw->alternateFunction);
timerConfigBase(ws2811TCH, period, WS2811_TIMER_MHZ);
timerPWMConfigChannel(ws2811TCH, 0);
timerPWMConfigChannelDMA(ws2811TCH, ledStripDMABuffer, WS2811_DMA_BUFFER_SIZE);
// Zero out DMA buffer
memset(&ledStripDMABuffer, 0, sizeof(ledStripDMABuffer));
ws2811Initialised = true;
ws2811UpdateStrip();
}
bool isWS2811LedStripReady(void)
{
return !timerPWMDMAInProgress(ws2811TCH);
}
STATIC_UNIT_TESTED uint16_t dmaBufferOffset;
static int16_t ledIndex;
STATIC_UNIT_TESTED void fastUpdateLEDDMABuffer(rgbColor24bpp_t *color)
{
uint32_t grb = (color->rgb.g << 16) | (color->rgb.r << 8) | (color->rgb.b);
for (int8_t index = 23; index >= 0; index--) {
ledStripDMABuffer[dmaBufferOffset++] = (grb & (1 << index)) ? BIT_COMPARE_1 : BIT_COMPARE_0;
}
}
/*
* This method is non-blocking unless an existing LED update is in progress.
* it does not wait until all the LEDs have been updated, that happens in the background.
*/
void ws2811UpdateStrip(void)
{
static rgbColor24bpp_t *rgb24;
// don't wait - risk of infinite block, just get an update next time round
if (timerPWMDMAInProgress(ws2811TCH)) {
return;
}
dmaBufferOffset = 0; // reset buffer memory index
ledIndex = 0; // reset led index
// fill transmit buffer with correct compare values to achieve
// correct pulse widths according to color values
while (ledIndex < WS2811_LED_STRIP_LENGTH)
{
rgb24 = hsvToRgb24(&ledColorBuffer[ledIndex]);
fastUpdateLEDDMABuffer(rgb24);
ledIndex++;
}
// Initiate hardware transfer
if (!ws2811Initialised || !ws2811TCH) {
return;
}
timerPWMPrepareDMA(ws2811TCH, WS2811_DMA_BUFFER_SIZE);
timerPWMStartDMA(ws2811TCH);
}
#endif