Add WS2812B driver (SPI-based)

README.md

@@ -73,12 +73,11 @@ STM32 devices, however, there are different levels of support and testing.
 
 <center>
 
-| Device Family | Support | Device Family | Support |
-|:--------------|:--------|:--------------|:--------|
-| AVR           | ★★★     | STM32F3       | ★★★★★   |
-| STM32F0       | ★★★★    | STM32F4       | ★★★★★   |
-| STM32F1       | ★★★★    | STM32F7       | ★★★★    |
-| STM32F2       | ★★★     | STM32L4       | ★★★★    |
+| Device Family | Support | Device Family | Support | Device Family | Support |
+|:--------------|:--------|:--------------|:--------|:--------------|:--------|
+| AVR           | ★★★     | STM32F2       | ★★★     | STM32F7       | ★★★★    |
+| STM32F0       | ★★★★    | STM32F3       | ★★★★★   | STM32L4       | ★★★★    |
+| STM32F1       | ★★★★    | STM32F4       | ★★★★★   | STM32G0       | ★★★★    |
 
 </center>
 
@@ -214,6 +213,7 @@ can easily configure them for you specific needs.
 <td align="center">VL53L0</td>
 </tr><tr>
 <td align="center">VL6180</td>
+<td align="center">WS2812</td>
 </tr>
 </table>
 <!--/drivertable-->

examples/README.md

@@ -94,7 +94,7 @@ make gdb
 
 ## Interesting Examples
 
-We have a lot of examples, <!--examplecount-->169<!--/examplecount--> to be
+We have a lot of examples, <!--examplecount-->170<!--/examplecount--> to be
 exact, but here are some of our favorite examples for our supported development
 boards:
 

examples/nucleo_f411re/ws2812b/main.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2019, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#include <modm/board.hpp>
+#include <modm/driver/pwm/ws2812b.hpp>
+#include <modm/ui/led/tables.hpp>
+#include <modm/processing/timer.hpp>
+
+using namespace Board;
+
+using Output = Board::D11;
+modm::Ws2812b<SpiMaster1, Output, 8*8> leds;
+modm::ShortPeriodicTimer tmr{33};
+
+int
+main()
+{
+	Board::initialize();
+	LedD13::setOutput();
+	leds.initialize<Board::SystemClock>();
+
+	constexpr uint8_t max = 62;
+	uint8_t r=0, g=max/3, b=max/3*2;
+
+	while (1)
+	{
+		for (size_t ii=0; ii < leds.size; ii++)
+		{
+			leds.setColor(ii,
+						  modm::ui::table22_8_256[r*3/2],
+						  modm::ui::table22_8_256[g*3/2],
+						  modm::ui::table22_8_256[b*3/2]);
+			if (r++ >= max) r = 0;
+			if (g++ >= max) g = 0;
+			if (b++ >= max) b = 0;
+		}
+		leds.write();
+
+		while(not tmr.execute()) ;
+		LedD13::toggle();
+	}
+
+	return 0;
+}

examples/nucleo_f411re/ws2812b/project.xml

@@ -0,0 +1,13 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<library>
+  <extends>modm:nucleo-f411re</extends>
+  <options>
+    <option name=":build:build.path">../../../build/nucleo_f411re/ws2812b</option>
+  </options>
+  <modules>
+    <module>:driver:ws2812</module>
+    <module>:platform:spi:1</module>
+    <module>:ui:led</module>
+    <module>:build:scons</module>
+  </modules>
+</library>

src/modm/driver/pwm/ws2812.lb

@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2019, Niklas Hauser
+#
+# This file is part of the modm project.
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+# -----------------------------------------------------------------------------
+
+
+def init(module):
+    module.parent = "driver"
+    module.name = "ws2812"
+    module.description = """\
+# WS2812 Driver
+
+Drives any number of chained WS2812 LEDs using a 3-bit SPI encoding
+(0 -> 100, 1 -> 110) running at 3 MHz.
+Thus, writing one LED takes 24µs and 9 bytes of memory.
+
+There are several caveats:
+
+1. This only provides a blocking write API, due to technical limitations.
+2. Atomicity is not enforced, this should be done externally if required.
+3. The memory footprint is 3x as large, due to the bit stuffing for SPI.
+4. There is no enforced reset period of at least 50µs after the write is finished,
+   it is up to the user to not trigger another write too early.
+
+This driver directly accesses the STM32 HAL to keep the transmit register full,
+due to a lack of DMA capability in modm, thus this driver is STM32-only for now.
+"""
+
+def prepare(module, options):
+    module.depends(
+        ":architecture:spi",
+        ":math:units")
+    return options[":target"].identifier.platform == "stm32"
+
+def build(env):
+    env.outbasepath = "modm/src/modm/driver/pwm"
+    env.copy("ws2812b.hpp")

src/modm/driver/pwm/ws2812b.hpp

@@ -0,0 +1,83 @@
+/*
+ * Copyright (c) 2019, Niklas Hauser
+ *
+ * This file is part of the modm project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+// ----------------------------------------------------------------------------
+
+#pragma once
+#include <modm/math/units.hpp>
+#include <modm/architecture/interface/spi_master.hpp>
+
+namespace modm
+{
+
+/// @ingroup modm_driver_ws2812
+template< class SpiMaster, class Output, size_t LEDs >
+class Ws2812b
+{										  // 7654 3210 7654 3210 7654 3210
+	static constexpr uint32_t base_mask  = 0b0010'0100'1001'0010'0100'1001;
+	static constexpr uint32_t clear_mask = base_mask << 1;
+
+	static constexpr size_t length = LEDs * 9;
+	uint8_t rgb[length + 1]; // +1 for zero byte for reset
+
+	static constexpr uint16_t
+	spread(uint8_t nibble)
+	{
+		return ((nibble & 0b0001) << 10) | ((nibble & 0b0010) << 6) |
+			   ((nibble & 0b0100) <<  5) | ((nibble & 0b1000) << 1);
+	}
+
+public:
+	static constexpr size_t size = LEDs;
+
+	Ws2812b()
+	{
+		size_t ii=0;
+		for (;ii < length; ii += 3)
+		{
+			*reinterpret_cast<uint32_t*>(rgb + ii) = base_mask;
+		}
+		rgb[length] = 0;
+	}
+
+	template< class SystemClock >
+	void
+	initialize()
+	{
+		SpiMaster::template connect<Output::template Mosi>();
+		SpiMaster::template initialize<SystemClock, MHz(3), pct(10)>();
+		SpiMaster::setDataOrder(SpiMaster::DataOrder::LsbFirst);
+		SpiMaster::Hal::write(uint8_t(0));
+	}
+
+	void
+	setColor(size_t index, uint8_t r, uint8_t g, uint8_t b)
+	{
+		if (index >= LEDs) return;
+
+		const uint8_t color[3] = {g, r, b};
+		for (size_t ii = 0; ii < 3; ii++)
+		{
+			const uint32_t c = (spread(color[ii]) << 12) | spread(color[ii] >> 4);
+			uint32_t *const value = reinterpret_cast<uint32_t*>(rgb + index * 9 + ii*3);
+			*value = (*value & ~clear_mask) | c;
+		}
+	}
+
+	void
+	write()
+	{
+		for (const auto data : rgb) {
+			while (not SpiMaster::Hal::isTransmitRegisterEmpty()) ;
+			SpiMaster::Hal::write(data);
+		}
+	}
+};
+
+}	// namespace modm

src/modm/platform/spi/stm32/spi_master.hpp.in

@@ -42,6 +42,8 @@ class SpiMaster{{ id }} : public modm::SpiMaster
 	static void *context;
 	static ConfigurationHandler configuration;
 public:
+	using Hal = SpiHal{{ id }};
+
 	/// Spi Data Mode, Mode0 is the most common mode
 	enum class
 	DataMode : uint32_t