Hack WS2811 led strip. Proof-of-concept.

Makefile

@@ -204,6 +204,7 @@ OLIMEXINO_SRC	 = startup_stm32f10x_md_gcc.S \
 		   drivers/compass_hmc5883l.c \
 		   drivers/gpio_stm32f10x.c \
 		   drivers/light_led_stm32f10x.c \
+		   drivers/light_ws2811strip.c \
 		   drivers/pwm_mapping.c \
 		   drivers/pwm_output.c \
 		   drivers/pwm_rssi.c \

src/main/drivers/light_ws2811strip.c

@@ -0,0 +1,196 @@
+/*
+ * 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/>.
+ */
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#include "platform.h"
+
+#include "common/axis.h"
+#include "common/maths.h"
+
+#define LED_STRIP_LENGTH 10
+
+static uint16_t LED_BYTE_Buffer[24 * LED_STRIP_LENGTH + 42];
+static volatile uint8_t ws2811LedDataTransferInProgress = 0;
+
+
+void ws2811LedStripInit(void)
+{
+    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
+    TIM_OCInitTypeDef  TIM_OCInitStructure;
+    GPIO_InitTypeDef GPIO_InitStructure;
+    DMA_InitTypeDef DMA_InitStructure;
+
+    uint16_t prescalerValue;
+
+    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
+    /* GPIOA Configuration: TIM3 Channel 1 as alternate function push-pull */
+    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
+    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
+    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
+    GPIO_Init(GPIOA, &GPIO_InitStructure);
+
+    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3, ENABLE);
+    /* Compute the prescaler value */
+    prescalerValue = (uint16_t) (SystemCoreClock / 24000000) - 1;
+    /* Time base configuration */
+    TIM_TimeBaseStructure.TIM_Period = 29; // 800kHz
+    TIM_TimeBaseStructure.TIM_Prescaler = prescalerValue;
+    TIM_TimeBaseStructure.TIM_ClockDivision = 0;
+    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
+    TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);
+
+    /* PWM1 Mode configuration: Channel1 */
+    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
+    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
+    TIM_OCInitStructure.TIM_Pulse = 0;
+    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
+    TIM_OC1Init(TIM3, &TIM_OCInitStructure);
+
+    /* configure DMA */
+    /* DMA clock enable */
+    RCC_AHBPeriphClockCmd(RCC_AHBPeriph_DMA1, ENABLE);
+
+    /* DMA1 Channel6 Config */
+    DMA_DeInit(DMA1_Channel6);
+
+    DMA_InitStructure.DMA_PeripheralBaseAddr = (uint32_t)&TIM3->CCR1;
+    DMA_InitStructure.DMA_MemoryBaseAddr = (uint32_t)LED_BYTE_Buffer;
+    DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralDST;
+    DMA_InitStructure.DMA_BufferSize = 42;
+    DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
+    DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
+    DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_HalfWord;
+    DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_HalfWord;
+    DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
+    DMA_InitStructure.DMA_Priority = DMA_Priority_High;
+    DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
+
+    DMA_Init(DMA1_Channel6, &DMA_InitStructure);
+
+    /* TIM3 CC1 DMA Request enable */
+    TIM_DMACmd(TIM3, TIM_DMA_CC1, ENABLE);
+
+    DMA_ITConfig(DMA1_Channel6, DMA_IT_TC, ENABLE);
+
+    NVIC_InitTypeDef NVIC_InitStructure;
+
+    NVIC_InitStructure.NVIC_IRQChannel = DMA1_Channel6_IRQn;
+    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 1;
+    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2;
+    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
+    NVIC_Init(&NVIC_InitStructure);
+}
+
+void DMA1_Channel6_IRQHandler(void)
+{
+    if (DMA_GetFlagStatus(DMA1_FLAG_TC6)) {
+        ws2811LedDataTransferInProgress = 0;
+        DMA_Cmd(DMA1_Channel6, DISABLE);            // disable DMA channel 6
+        DMA_ClearFlag(DMA1_FLAG_TC6);               // clear DMA1 Channel 6 transfer complete flag
+    }
+}
+
+
+/* This function sends data bytes out to a string of WS2812s
+ * The first argument is a pointer to the first RGB triplet to be sent
+ * The seconds argument is the number of LEDs in the chain
+ *
+ * This will result in the RGB triplet passed by argument 1 being sent to
+ * the LED that is the furthest away from the controller (the point where
+ * data is injected into the chain)
+ *
+ * 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 ws2812SetStripColors(const uint8_t (*color)[3], uint16_t len)
+{
+    uint8_t j;
+    uint8_t led;
+    uint16_t memaddr;
+    uint16_t buffersize;
+
+    while(ws2811LedDataTransferInProgress);   // wait until previous transfer completes
+
+    buffersize = (len*24)+42;   // number of bytes needed is #LEDs * 24 bytes + 42 trailing bytes
+    memaddr = 0;                // reset buffer memory index
+    led = 0;                    // reset led index
+
+    // fill transmit buffer with correct compare values to achieve
+    // correct pulse widths according to color values
+    while (len)
+    {
+        for (j = 0; j < 8; j++)                 // GREEN data
+        {
+            if ( (color[led][1]<<j) & 0x80 )    // data sent MSB first, j = 0 is MSB j = 7 is LSB
+            {
+                LED_BYTE_Buffer[memaddr] = 17;  // compare value for logical 1
+            }
+            else
+            {
+                LED_BYTE_Buffer[memaddr] = 9;   // compare value for logical 0
+            }
+            memaddr++;
+        }
+
+        for (j = 0; j < 8; j++)                 // RED data
+        {
+            if ( (color[led][0]<<j) & 0x80 )    // data sent MSB first, j = 0 is MSB j = 7 is LSB
+            {
+                LED_BYTE_Buffer[memaddr] = 17;  // compare value for logical 1
+            }
+            else
+            {
+                LED_BYTE_Buffer[memaddr] = 9;   // compare value for logical 0
+            }
+            memaddr++;
+        }
+
+        for (j = 0; j < 8; j++)                 // BLUE data
+        {
+            if ( (color[led][2]<<j) & 0x80 )    // data sent MSB first, j = 0 is MSB j = 7 is LSB
+            {
+                LED_BYTE_Buffer[memaddr] = 17;  // compare value for logical 1
+            }
+            else
+            {
+                LED_BYTE_Buffer[memaddr] = 9;   // compare value for logical 0
+            }
+            memaddr++;
+        }
+
+        led++;
+        len--;
+    }
+
+    // add needed delay at end of byte cycle, pulsewidth = 0
+    while(memaddr < buffersize)
+    {
+        LED_BYTE_Buffer[memaddr] = 0;
+        memaddr++;
+    }
+
+    ws2811LedDataTransferInProgress = 1;
+
+    DMA_SetCurrDataCounter(DMA1_Channel6, buffersize);  // load number of bytes to be transferred
+    TIM_SetCounter(TIM3, 0);
+    TIM_Cmd(TIM3, ENABLE);                      // enable Timer 3
+    DMA_Cmd(DMA1_Channel6, ENABLE);             // enable DMA channel 6
+}
+
+

src/main/drivers/light_ws2811strip.h

@@ -0,0 +1,22 @@
+/*
+ * 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/>.
+ */
+
+#pragma once
+
+void ws2811LedStripInit(void);
+void ws2812SetStripColors(const uint8_t (*color)[3], uint16_t ledCount);
+

src/main/main.c

@@ -26,6 +26,7 @@
 #include "drivers/system.h"
 #include "drivers/gpio.h"
 #include "drivers/light_led.h"
+#include "drivers/light_ws2811strip.h"
 #include "drivers/sound_beeper.h"
 #include "drivers/timer.h"
 #include "drivers/serial.h"
@@ -214,6 +215,8 @@ void init(void)
     }
 #endif
 
+    ws2811LedStripInit();
+
     if (feature(FEATURE_TELEMETRY))
         initTelemetry();
 

src/main/mw.c

@@ -28,6 +28,8 @@
 #include "drivers/accgyro.h"
 #include "drivers/light_ledring.h"
 #include "drivers/light_led.h"
+#include "drivers/light_ws2811strip.h"
+
 #include "drivers/gpio.h"
 #include "drivers/system.h"
 #include "drivers/serial.h"
@@ -346,6 +348,82 @@ void updateInflightCalibrationState(void)
     }
 }
 
+static const uint8_t colors[][3] =
+{
+    {255, 0,   0},
+    {0,   255, 0},
+    {0,   0,   255},
+    {255, 0,   255},
+
+    {255, 255, 255},
+    {255, 255, 255},
+
+    {255, 255, 0},
+    {0,   0,   255},
+    {0,   255, 0},
+    {255, 0,   0}
+};
+
+
+static const uint8_t stripOff[][3] =
+{
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+    {0,   0,   0},
+};
+
+static const uint8_t stripRed[][3] =
+{
+    {32,   0,   0},
+    {96,   0,   0},
+    {160,   0,   0},
+    {224,   0,   0},
+    {255,   0,   0},
+    {255,   0,   0},
+    {224,   0,   0},
+    {160,   0,   0},
+    {96,   0,   0},
+    {32,   0,   0},
+};
+
+uint32_t lastStripUpdateAt = 0;
+
+#define LED_STRIP_50HZ ((1000 * 1000) / 50)
+
+void updateLedStrip(void)
+{
+    uint32_t now = micros();
+
+    if (now - lastStripUpdateAt < LED_STRIP_50HZ) {
+        return;
+    }
+
+    lastStripUpdateAt = now;
+
+    static uint8_t stripState = 0;
+
+    if (stripState == 0) {
+        if (f.ARMED) {
+            ws2812SetStripColors(stripRed, 10);
+        } else {
+            ws2812SetStripColors(colors, 10);
+        }
+        stripState = 1;
+    } else {
+        ws2812SetStripColors(stripOff, 10);
+        stripState = 0;
+    }
+}
+
+
+
 void loop(void)
 {
     int i;
@@ -628,5 +706,5 @@ void loop(void)
     if (!cliMode && feature(FEATURE_TELEMETRY)) {
         handleTelemetry();
     }
-
+    updateLedStrip();
 }