sample/rain: simulated rain drops which fade over time

soft/sample/rain/fade.config

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+/*! \file fade.config
+ *
+ *  \brief Coordinated up/down fading configuration
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This macro defines the PWM channels of each participating LED.
+ *
+ * The fade engine calculates a PWM setting in the range 0..255 according
+ * to the master PWM target, the current PWM setting and the rate of change
+ *
+ * A selector macro is passed which will choose a parameter from the
+ * configuration. For example, if you want to control PWM channels 1, 0 and 3
+ * use the macro like this
+ *
+ * @code
+ * #define FADE_PWMS(_) _(1) _(0) _(3)
+ * @endcode
+ */
+
+#define FADE_PWMS(_) _(0) _(1) _(2) _(3) _(4)

soft/sample/rain/pwm.config

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+/*! \file pwm.config
+ *
+ *  \brief Software Pulse Width Modulation configuration
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * This macro defines the GPIOs configured to be used as PWM outputs.
+ *
+ * A selector macro is passed which will choose a parameter from the
+ * configuration. For example, if you want to set PB5 and PB2 to be
+ * PWM channels 0 and 1 respectively use the macro like this
+ *
+ * @code
+ * #define PWM_GPIOS(_) _(B, 5) _(B, 2)
+ * @endcode
+ */
+
+#define PWM_GPIOS(_) _(B, 0) _(B, 1) _(B, 2) _(B, 3) _(B, 4)

soft/sample/rain/rain.c

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+/*! \file rain.c
+ *
+ *  \brief Rain effect on LEDs
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "task.h"
+#include "fade.h"
+#include "pwm.h"
+#include "random.h"
+
+#include <stdint.h>
+
+#define RAIN_TICK 100
+#define RAIN_DISPERSE 80
+#define RAIN_SPREAD 50
+
+static uint8_t rain_task(uint8_t ms_later)
+{
+    static uint8_t wait;
+
+    switch(ms_later)
+    {
+    case TASK_STARTUP:
+        wait = 0;
+        /* Fade to black */
+        fade_set_brightness(0);
+        fade_set_update(RAIN_DISPERSE);
+        fade_set_rate_linear(8);
+        break;
+    case TASK_SHUTDOWN:
+        break;
+    default:
+        wait += ms_later;
+        if (wait >= RAIN_TICK)
+        {
+            /* pwm_set() ignores addressing a non-existent channel */
+            pwm_set(random_get(RAIN_SPREAD), 255);
+            wait = 0;
+        }        
+        break;
+    }
+
+    return RAIN_TICK-wait;
+}
+
+TASK_DECLARE(rain_task);