Add simple driver for HX711 weight scale / bridge amplifier and integrated ADC

README.md

@@ -193,44 +193,45 @@ can easily configure them for you specific needs.
 <td align="center">HD44780</td>
 <td align="center">HMC58x</td>
 <td align="center">HMC6343</td>
+<td align="center">HX711</td>
 <td align="center">I2C-EEPROM</td>
-<td align="center">ITG3200</td>
 </tr><tr>
+<td align="center">ITG3200</td>
 <td align="center">L3GD20</td>
 <td align="center">LAWICEL</td>
 <td align="center">LIS302DL</td>
 <td align="center">LIS3DSH</td>
 <td align="center">LM75</td>
-<td align="center">LSM303A</td>
 </tr><tr>
+<td align="center">LSM303A</td>
 <td align="center">LTC2984</td>
 <td align="center">MAX6966</td>
 <td align="center">MAX7219</td>
 <td align="center">MCP23X17</td>
 <td align="center">MCP2515</td>
-<td align="center">NOKIA5110</td>
 </tr><tr>
+<td align="center">NOKIA5110</td>
 <td align="center">NRF24</td>
 <td align="center">TFT-DISPLAY</td>
 <td align="center">PAT9125EL</td>
 <td align="center">PCA8574</td>
 <td align="center">PCA9535</td>
-<td align="center">PCA9548A</td>
 </tr><tr>
+<td align="center">PCA9548A</td>
 <td align="center">PCA9685</td>
 <td align="center">SIEMENS-S65</td>
 <td align="center">SIEMENS-S75</td>
 <td align="center">SK6812</td>
 <td align="center">SK9822</td>
-<td align="center">SSD1306</td>
 </tr><tr>
+<td align="center">SSD1306</td>
 <td align="center">TCS3414</td>
 <td align="center">TCS3472</td>
 <td align="center">TLC594X</td>
 <td align="center">TMP102</td>
 <td align="center">TMP175</td>
-<td align="center">VL53L0</td>
 </tr><tr>
+<td align="center">VL53L0</td>
 <td align="center">VL6180</td>
 <td align="center">WS2812</td>
 </tr>

examples/stm32f103c8t6_blue_pill/weight_scale_hx711/main.cpp

@@ -0,0 +1,123 @@
+/*
+ * Copyright (c) 2020, Sascha Schade
+ *
+ * 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/debug/logger.hpp>
+#include <modm/processing/timer.hpp>
+#include <modm/processing/protothread.hpp>
+#include <modm/driver/adc/hx711.hpp>
+using namespace modm::literals;
+
+using namespace Board;
+
+// ----------------------------------------------------------------------------
+// Set the log level
+#undef	MODM_LOG_LEVEL
+#define	MODM_LOG_LEVEL modm::log::DEBUG
+
+// Create an IODeviceWrapper around the Uart Peripheral we want to use
+modm::IODeviceWrapper< Usart1, modm::IOBuffer::BlockIfFull > loggerDevice;
+
+// Set all four logger streams to use the UART
+modm::log::Logger modm::log::debug(loggerDevice);
+modm::log::Logger modm::log::info(loggerDevice);
+modm::log::Logger modm::log::warning(loggerDevice);
+modm::log::Logger modm::log::error(loggerDevice);
+
+
+struct hx711_config : public modm::hx711::Config
+{
+	using Sck  = GpioOutputA9;
+	using Data = GpioInputA10;
+	// static const modm::hx711::InputChannelAndGain mode = modm::hx711::InputChannelAndGain::ChA_64;
+};
+using Hx711 = modm::Hx711< hx711_config >;
+
+class Hx711Thread : public modm::pt::Protothread
+{
+public:
+	bool
+	run()
+	{
+		PT_BEGIN();
+
+		while (true)
+		{
+			result = PT_CALL(hx711.singleConversion());
+			MODM_LOG_DEBUG.printf("%" PRIi32 "\n", result);
+		}
+
+		PT_END();
+	}
+
+protected:
+	Hx711 hx711;
+	int32_t result;
+};
+
+Hx711Thread hx711_thread;
+
+
+class BlinkThread : public modm::pt::Protothread
+{
+public:
+	bool
+	run()
+	{
+		PT_BEGIN();
+
+		while (true) {
+			PT_WAIT_UNTIL(timer.execute());
+			LedGreen::toggle();
+		}
+
+		PT_END();
+	}
+
+protected:
+	modm::ShortPeriodicTimer timer{1'000};
+};
+
+BlinkThread blink_thread;
+
+
+/*
+ * Blinks the green user LED with 1 Hz while measuring.
+ *
+ * Make the following connections to HX711:
+ *   Data PA10
+ *   Clock PA9
+ */
+int
+main()
+{
+	Board::initialize();
+
+	// Initialize Uart1 for MODM_LOG_*
+	Usart1::connect<GpioOutputB6::Tx, GpioInputB7::Rx>();
+	Usart1::initialize<Board::SystemClock, 115200_Bd>();
+
+	// Use the logging streams to print some messages.
+	MODM_LOG_DEBUG   << "HX711 demo"   << modm::endl;
+
+	hx711_config::Sck::setOutput();
+	hx711_config::Data::setInput();
+
+	LedGreen::set();
+
+	while (true)
+	{
+		blink_thread.run();
+		hx711_thread.run();
+	}
+
+	return 0;
+}

examples/stm32f103c8t6_blue_pill/weight_scale_hx711/openocd.cfg

@@ -0,0 +1,2 @@
+# Replace this with your custom programmer
+source [find interface/stlink-v2.cfg]

examples/stm32f103c8t6_blue_pill/weight_scale_hx711/project.xml

@@ -0,0 +1,16 @@
+<library>
+  <extends>modm:blue-pill</extends>
+  <options>
+    <option name="modm:build:build.path">../../../build/stm32f103c8t6_blue_pill/weight_scale_hx711</option>
+    <option name="modm:build:openocd.cfg">openocd.cfg</option>
+  </options>
+  <modules>
+    <module>modm:debug</module>
+    <module>modm:platform:gpio</module>
+    <module>modm:platform:uart:1</module>
+    <module>modm:processing:timer</module>
+    <module>modm:processing:protothread</module>
+    <module>modm:build:scons</module>
+    <module>modm:driver:hx711</module>
+  </modules>
+</library>

src/modm/driver/adc/hx711.hpp

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2020, Sascha Schade
+ *
+ * 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/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_HX711_HPP
+#define MODM_HX711_HPP
+
+#include <modm/architecture/interface/delay.hpp>
+#include <modm/processing/resumable.hpp>
+
+namespace modm
+{
+
+/// @ingroup modm_driver_hx711
+struct hx711
+{
+	enum class
+	InputChannelAndGain : uint8_t
+	{
+		ChA_128 = 1,
+		ChB_32 = 2,
+		ChA_64 = 3
+	};
+
+	struct Config
+	{
+		using Sck = void; // required
+		using Data = void; // required
+		static const InputChannelAndGain mode = InputChannelAndGain::ChA_128;
+	};
+};
+
+template <typename Cfg>
+class Hx711 : public hx711, protected modm::NestedResumable<2>
+{
+	using Sck = typename Cfg::Sck;
+	using Data = typename Cfg::Data;
+
+public:
+	modm::ResumableResult<int32_t>
+	singleConversion();
+
+private:
+	int32_t data;
+};
+
+} // modm namespace
+
+#include "hx711_impl.hpp"
+
+#endif // MODM_HX711_HPP

src/modm/driver/adc/hx711.lb

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+#
+# Copyright (c) 2020, Sascha Schade
+#
+# 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.name = ":driver:hx711"
+    module.description = """\
+# HX711 Load Cell Amplifier and ADC
+
+The HX711 is an integrated load cell amplifier designed for weight scales and
+industrial control applications to interface directly with a bridge sensor.
+The interface is bit-bang and timing based, so only GPIO is needed.
+In a complete system the SCK pin's timing while reading must be met.
+"""
+
+
+def prepare(module, options):
+    module.depends(
+        ":architecture:delay",
+        ":architecture:gpio",
+        ":processing:resumable")
+    return True
+
+def build(env):
+    env.outbasepath = "modm/src/modm/driver/adc"
+    env.copy("hx711.hpp")
+    env.copy("hx711_impl.hpp")

src/modm/driver/adc/hx711_impl.hpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2020, Sascha Schade
+ *
+ * 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/.
+ */
+// ----------------------------------------------------------------------------
+
+#ifndef MODM_HX711_HPP
+#	error "Don't include this file directly! Use 'hx711.hpp' instead."
+#endif
+
+namespace modm
+{
+
+template <typename Cfg>
+ResumableResult<int32_t>
+Hx711<Cfg>::singleConversion()
+{
+	RF_BEGIN();
+
+	RF_WAIT_UNTIL(Data::read() == modm::Gpio::Low);
+
+	modm::delayMicroseconds(1);
+
+	data = 0;
+	for (uint8_t ii = 0; ii < 24; ++ii)
+	{
+		Sck::set();
+		modm::delayMicroseconds(1);
+		data = (data << 1) | Data::read();
+		modm::delayMicroseconds(1);
+		Sck::reset();
+		modm::delayMicroseconds(1);
+	}
+
+	// Additional pulses for mode of next conversion
+	for (uint8_t ii = 0; ii < static_cast<uint8_t>(Cfg::mode); ++ii) {
+		Sck::set();
+		modm::delayMicroseconds(1);
+		Sck::reset();
+		modm::delayMicroseconds(1);
+	}
+
+	// Fill up MSBs for negative numbers
+	if (data & (1 << 23)) {
+		data |= 0xff000000;
+	}
+
+	RF_END_RETURN(data);
+}
+
+} // modm namespace