Merge pull request #258 from jgoppert/md25

MD25 Motor Controller Driver

apps/drivers/device/i2c.h

@@ -53,6 +53,15 @@ namespace device __EXPORT
 class __EXPORT I2C : public CDev
 {
 
+public:
+
+    /**
+     * Get the address
+     */
+    uint16_t get_address() {
+      return _address;
+    }
+
 protected:
 	/**
 	 * The number of times a read or write operation will be retried on

apps/drivers/md25/MD25.cpp

+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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 OWNER 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file md25.cpp
+ *
+ * Driver for MD25 I2C Motor Driver
+ *
+ * references:
+ * http://www.robot-electronics.co.uk/htm/md25tech.htm
+ * http://www.robot-electronics.co.uk/files/rpi_md25.c
+ *
+ */
+
+#include "MD25.hpp"
+#include <poll.h>
+#include <stdio.h>
+
+#include <systemlib/err.h>
+#include <arch/board/board.h>
+
+// registers
+enum {
+	// RW: read/write
+	// R: read
+	REG_SPEED1_RW = 0,
+	REG_SPEED2_RW,
+	REG_ENC1A_R,
+	REG_ENC1B_R,
+	REG_ENC1C_R,
+	REG_ENC1D_R,
+	REG_ENC2A_R,
+	REG_ENC2B_R,
+	REG_ENC2C_R,
+	REG_ENC2D_R,
+	REG_BATTERY_VOLTS_R,
+	REG_MOTOR1_CURRENT_R,
+	REG_MOTOR2_CURRENT_R,
+	REG_SW_VERSION_R,
+	REG_ACCEL_RATE_RW,
+	REG_MODE_RW,
+	REG_COMMAND_RW,
+};
+
+MD25::MD25(const char *deviceName, int bus,
+	   uint16_t address, uint32_t speed) :
+	I2C("MD25", deviceName, bus, address, speed),
+	_controlPoll(),
+	_actuators(NULL, ORB_ID(actuator_controls_0), 20),
+	_version(0),
+	_motor1Speed(0),
+	_motor2Speed(0),
+	_revolutions1(0),
+	_revolutions2(0),
+	_batteryVoltage(0),
+	_motor1Current(0),
+	_motor2Current(0),
+	_motorAccel(0),
+	_mode(MODE_UNSIGNED_SPEED),
+	_command(CMD_RESET_ENCODERS)
+{
+	// setup control polling
+	_controlPoll.fd = _actuators.getHandle();
+	_controlPoll.events = POLLIN;
+
+	// if initialization fails raise an error, unless
+	// probing
+	int ret = I2C::init();
+
+	if (ret != OK) {
+		warnc(ret, "I2C::init failed for bus: %d address: %d\n", bus, address);
+	}
+
+	// setup default settings, reset encoders
+	setMotor1Speed(0);
+	setMotor2Speed(0);
+	resetEncoders();
+	_setMode(MD25::MODE_UNSIGNED_SPEED);
+	setSpeedRegulation(true);
+	setTimeout(true);
+}
+
+MD25::~MD25()
+{
+}
+
+int MD25::readData()
+{
+	uint8_t sendBuf[1];
+	sendBuf[0] = REG_SPEED1_RW;
+	uint8_t recvBuf[17];
+	int ret = transfer(sendBuf, sizeof(sendBuf),
+			   recvBuf, sizeof(recvBuf));
+
+	if (ret == OK) {
+		_version = recvBuf[REG_SW_VERSION_R];
+		_motor1Speed = _uint8ToNorm(recvBuf[REG_SPEED1_RW]);
+		_motor2Speed = _uint8ToNorm(recvBuf[REG_SPEED2_RW]);
+		_revolutions1 = -int32_t((recvBuf[REG_ENC1A_R] << 24) +
+					 (recvBuf[REG_ENC1B_R] << 16) +
+					 (recvBuf[REG_ENC1C_R] << 8)  +
+					 recvBuf[REG_ENC1D_R]) / 360.0;
+		_revolutions2 = -int32_t((recvBuf[REG_ENC2A_R] << 24) +
+					 (recvBuf[REG_ENC2B_R] << 16) +
+					 (recvBuf[REG_ENC2C_R] << 8)  +
+					 recvBuf[REG_ENC2D_R]) / 360.0;
+		_batteryVoltage = recvBuf[REG_BATTERY_VOLTS_R] / 10.0;
+		_motor1Current = recvBuf[REG_MOTOR1_CURRENT_R] / 10.0;
+		_motor2Current = recvBuf[REG_MOTOR2_CURRENT_R] / 10.0;
+		_motorAccel = recvBuf[REG_ACCEL_RATE_RW];
+		_mode = e_mode(recvBuf[REG_MODE_RW]);
+		_command = e_cmd(recvBuf[REG_COMMAND_RW]);
+	}
+
+	return ret;
+}
+
+void MD25::status(char *string, size_t n)
+{
+	snprintf(string, n,
+		 "version:\t%10d\n" \
+		 "motor 1 speed:\t%10.2f\n" \
+		 "motor 2 speed:\t%10.2f\n" \
+		 "revolutions 1:\t%10.2f\n" \
+		 "revolutions 2:\t%10.2f\n" \
+		 "battery volts :\t%10.2f\n" \
+		 "motor 1 current :\t%10.2f\n" \
+		 "motor 2 current :\t%10.2f\n" \
+		 "motor accel :\t%10d\n" \
+		 "mode :\t%10d\n" \
+		 "command :\t%10d\n",
+		 getVersion(),
+		 double(getMotor1Speed()),
+		 double(getMotor2Speed()),
+		 double(getRevolutions1()),
+		 double(getRevolutions2()),
+		 double(getBatteryVolts()),
+		 double(getMotor1Current()),
+		 double(getMotor2Current()),
+		 getMotorAccel(),
+		 getMode(),
+		 getCommand());
+}
+
+uint8_t MD25::getVersion()
+{
+	return _version;
+}
+
+float MD25::getMotor1Speed()
+{
+	return _motor1Speed;
+}
+
+float MD25::getMotor2Speed()
+{
+	return _motor2Speed;
+}
+
+float MD25::getRevolutions1()
+{
+	return _revolutions1;
+}
+
+float MD25::getRevolutions2()
+{
+	return _revolutions2;
+}
+
+float MD25::getBatteryVolts()
+{
+	return _batteryVoltage;
+}
+
+float MD25::getMotor1Current()
+{
+	return _motor1Current;
+}
+float MD25::getMotor2Current()
+{
+	return _motor2Current;
+}
+
+uint8_t MD25::getMotorAccel()
+{
+	return _motorAccel;
+}
+
+MD25::e_mode MD25::getMode()
+{
+	return _mode;
+}
+
+MD25::e_cmd MD25::getCommand()
+{
+	return _command;
+}
+
+int MD25::resetEncoders()
+{
+	return _writeUint8(REG_COMMAND_RW,
+			   CMD_RESET_ENCODERS);
+}
+
+int MD25::_setMode(e_mode mode)
+{
+	return _writeUint8(REG_MODE_RW,
+			   mode);
+}
+
+int MD25::setSpeedRegulation(bool enable)
+{
+	if (enable) {
+		return _writeUint8(REG_COMMAND_RW,
+				   CMD_ENABLE_SPEED_REGULATION);
+
+	} else {
+		return _writeUint8(REG_COMMAND_RW,
+				   CMD_DISABLE_SPEED_REGULATION);
+	}
+}
+
+int MD25::setTimeout(bool enable)
+{
+	if (enable) {
+		return _writeUint8(REG_COMMAND_RW,
+				   CMD_ENABLE_TIMEOUT);
+
+	} else {
+		return _writeUint8(REG_COMMAND_RW,
+				   CMD_DISABLE_TIMEOUT);
+	}
+}
+
+int MD25::setDeviceAddress(uint8_t address)
+{
+	uint8_t sendBuf[1];
+	sendBuf[0] = CMD_CHANGE_I2C_SEQ_0;
+	int ret = OK;
+	ret = transfer(sendBuf, sizeof(sendBuf),
+		       nullptr, 0);
+
+	if (ret != OK) {
+		warnc(ret, "MD25::setDeviceAddress");
+		return ret;
+	}
+
+	usleep(5000);
+	sendBuf[0] = CMD_CHANGE_I2C_SEQ_1;
+	ret = transfer(sendBuf, sizeof(sendBuf),
+		       nullptr, 0);
+
+	if (ret != OK) {
+		warnc(ret, "MD25::setDeviceAddress");
+		return ret;
+	}
+
+	usleep(5000);
+	sendBuf[0] = CMD_CHANGE_I2C_SEQ_2;
+	ret = transfer(sendBuf, sizeof(sendBuf),
+		       nullptr, 0);
+
+	if (ret != OK) {
+		warnc(ret, "MD25::setDeviceAddress");
+		return ret;
+	}
+
+	return OK;
+}
+
+int MD25::setMotor1Speed(float value)
+{
+	return _writeUint8(REG_SPEED1_RW,
+			   _normToUint8(value));
+}
+
+int MD25::setMotor2Speed(float value)
+{
+	return _writeUint8(REG_SPEED2_RW,
+			   _normToUint8(value));
+}
+
+void MD25::update()
+{
+	// wait for an actuator publication,
+	// check for exit condition every second
+	// note "::poll" is required to distinguish global
+	// poll from member function for driver
+	if (::poll(&_controlPoll, 1, 1000) < 0) return; // poll error
+
+	// if new data, send to motors
+	if (_actuators.updated()) {
+		_actuators.update();
+		setMotor1Speed(_actuators.control[CH_SPEED_LEFT]);
+		setMotor2Speed(_actuators.control[CH_SPEED_RIGHT]);
+	}
+}
+
+int MD25::probe()
+{
+	uint8_t goodAddress = 0;
+	bool found = false;
+	int ret = OK;
+
+	// try initial address first, if good, then done
+	if (readData() == OK) return ret;
+
+	// try all other addresses
+	uint8_t testAddress = 0;
+
+	//printf("searching for MD25 address\n");
+	while (true) {
+		set_address(testAddress);
+		ret = readData();
+
+		if (ret == OK && !found) {
+			//printf("device found at address: 0x%X\n", testAddress);
+			if (!found) {
+				found = true;
+				goodAddress = testAddress;
+			}
+		}
+
+		if (testAddress > 254) {
+			break;
+		}
+
+		testAddress++;
+	}
+
+	if (found) {
+		set_address(goodAddress);
+		return OK;
+
+	} else {
+		set_address(0);
+		return ret;
+	}
+}
+
+int MD25::search()
+{
+	uint8_t goodAddress = 0;
+	bool found = false;
+	int ret = OK;
+	// try all other addresses
+	uint8_t testAddress = 0;
+
+	//printf("searching for MD25 address\n");
+	while (true) {
+		set_address(testAddress);
+		ret = readData();
+
+		if (ret == OK && !found) {
+			printf("device found at address: 0x%X\n", testAddress);
+
+			if (!found) {
+				found = true;
+				goodAddress = testAddress;
+			}
+		}
+
+		if (testAddress > 254) {
+			break;
+		}
+
+		testAddress++;
+	}
+
+	if (found) {
+		set_address(goodAddress);
+		return OK;
+
+	} else {
+		set_address(0);
+		return ret;
+	}
+}
+
+int MD25::_writeUint8(uint8_t reg, uint8_t value)
+{
+	uint8_t sendBuf[2];
+	sendBuf[0] = reg;
+	sendBuf[1] = value;
+	return transfer(sendBuf, sizeof(sendBuf),
+			nullptr, 0);
+}
+
+int MD25::_writeInt8(uint8_t reg, int8_t value)
+{
+	uint8_t sendBuf[2];
+	sendBuf[0] = reg;
+	sendBuf[1] = value;
+	return transfer(sendBuf, sizeof(sendBuf),
+			nullptr, 0);
+}
+
+float MD25::_uint8ToNorm(uint8_t value)
+{
+	// TODO, should go from 0 to 255
+	// possibly should handle this differently
+	return (value - 128) / 127.0;
+}
+
+uint8_t MD25::_normToUint8(float value)
+{
+	if (value > 1) value = 1;
+
+	if (value < -1) value = -1;
+
+	// TODO, should go from 0 to 255
+	// possibly should handle this differently
+	return 127 * value + 128;
+}
+
+int md25Test(const char *deviceName, uint8_t bus, uint8_t address)
+{
+	printf("md25 test: starting\n");
+
+	// setup
+	MD25 md25("/dev/md25", bus, address);
+
+	// print status
+	char buf[200];
+	md25.status(buf, sizeof(buf));
+	printf("%s\n", buf);
+
+	// setup for test
+	md25.setSpeedRegulation(true);
+	md25.setTimeout(true);
+	float dt = 0.1;
+	float speed = 0.2;
+	float t = 0;
+
+	// motor 1 test
+	printf("md25 test: spinning motor 1 forward for 1 rev at 0.1 speed\n");
+	t = 0;
+
+	while (true) {
+		t += dt;
+		md25.setMotor1Speed(speed);
+		md25.readData();
+		usleep(1000000 * dt);
+
+		if (md25.getRevolutions1() > 1) {
+			printf("finished 1 revolution fwd\n");
+			break;
+		}
+
+		if (t > 2.0f) break;
+	}
+
+	md25.setMotor1Speed(0);
+	printf("revolution of wheel 1: %8.4f\n", double(md25.getRevolutions1()));
+	md25.resetEncoders();
+
+	t = 0;
+
+	while (true) {
+		t += dt;
+		md25.setMotor1Speed(-speed);
+		md25.readData();
+		usleep(1000000 * dt);
+
+		if (md25.getRevolutions1() < -1) {
+			printf("finished 1 revolution rev\n");
+			break;
+		}
+
+		if (t > 2.0f) break;
+	}
+
+	md25.setMotor1Speed(0);
+	printf("revolution of wheel 1: %8.4f\n", double(md25.getRevolutions1()));
+	md25.resetEncoders();
+
+	// motor 2 test
+	printf("md25 test: spinning motor 2 forward for 1 rev at 0.1 speed\n");
+	t = 0;
+
+	while (true) {
+		t += dt;
+		md25.setMotor2Speed(speed);
+		md25.readData();
+		usleep(1000000 * dt);
+
+		if (md25.getRevolutions2() > 1) {
+			printf("finished 1 revolution fwd\n");
+			break;
+		}
+
+		if (t > 2.0f) break;
+	}
+
+	md25.setMotor2Speed(0);
+	printf("revolution of wheel 2: %8.4f\n", double(md25.getRevolutions2()));
+	md25.resetEncoders();
+
+	t = 0;
+
+	while (true) {
+		t += dt;
+		md25.setMotor2Speed(-speed);
+		md25.readData();
+		usleep(1000000 * dt);
+
+		if (md25.getRevolutions2() < -1) {
+			printf("finished 1 revolution rev\n");
+			break;
+		}
+
+		if (t > 2.0f) break;
+	}
+
+	md25.setMotor2Speed(0);
+	printf("revolution of wheel 2: %8.4f\n", double(md25.getRevolutions2()));
+	md25.resetEncoders();
+
+	printf("Test complete\n");
+	return 0;
+}
+
+// vi:noet:smarttab:autoindent:ts=4:sw=4:tw=78

apps/drivers/md25/MD25.hpp

+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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 OWNER 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.
+ *
+ ****************************************************************************/
+
+/**
+ * @file md25.cpp
+ *
+ * Driver for MD25 I2C Motor Driver
+ *
+ * references:
+ * http://www.robot-electronics.co.uk/htm/md25tech.htm
+ * http://www.robot-electronics.co.uk/files/rpi_md25.c
+ *
+ */
+
+#pragma once
+
+#include <poll.h>
+#include <stdio.h>
+#include <controllib/block/UOrbSubscription.hpp>
+#include <uORB/topics/actuator_controls.h>
+#include <drivers/device/i2c.h>
+
+/**
+ * This is a driver for the MD25 motor controller utilizing the I2C interface.
+ */
+class MD25 : public device::I2C
+{
+public:
+
+	/**
+	* modes
+	*
+	* NOTE: this driver assumes we are always
+	* in mode 0!
+	*
+	* seprate speed mode:
+	*  motor speed1 = speed1
+	*  motor speed2 = speed2
+	* turn speed mode:
+	*	motor speed1 = speed1 + speed2
+	*  motor speed2 = speed2 - speed2
+	* unsigned:
+	*  full rev (0), stop(128), full fwd (255)
+	* signed:
+	*  full rev (-127), stop(0), full fwd (128)
+	*
+	* modes numbers:
+	* 0 : unsigned separate (default)
+	* 1 : signed separate
+	* 2 : unsigned turn
+	* 3 : signed turn
+	*/
+	enum e_mode {
+		MODE_UNSIGNED_SPEED = 0,
+		MODE_SIGNED_SPEED,
+		MODE_UNSIGNED_SPEED_TURN,
+		MODE_SIGNED_SPEED_TURN,
+	};
+
+	/** commands */
+	enum e_cmd {
+		CMD_RESET_ENCODERS = 32,
+		CMD_DISABLE_SPEED_REGULATION = 48,
+		CMD_ENABLE_SPEED_REGULATION = 49,
+		CMD_DISABLE_TIMEOUT = 50,
+		CMD_ENABLE_TIMEOUT = 51,
+		CMD_CHANGE_I2C_SEQ_0 = 160,
+		CMD_CHANGE_I2C_SEQ_1 = 170,
+		CMD_CHANGE_I2C_SEQ_2 = 165,
+	};
+
+	/** control channels */
+	enum e_channels {
+		CH_SPEED_LEFT = 0,
+		CH_SPEED_RIGHT
+	};
+
+	/**
+	 * constructor
+	 * @param deviceName the name of the device e.g. "/dev/md25"
+	 * @param bus the I2C bus
+	 * @param address the adddress on the I2C bus
+	 * @param speed the speed of the I2C communication
+	 */
+	MD25(const char *deviceName,
+	     int bus,
+	     uint16_t address,
+	     uint32_t speed = 100000);
+
+	/**
+	 * deconstructor
+	 */
+	virtual ~MD25();
+
+	/**
+	 * @return software version
+	 */
+	uint8_t getVersion();
+
+	/**
+	 * @return speed of motor, normalized (-1, 1)
+	 */
+	float getMotor1Speed();
+
+	/**
+	 * @return speed of motor 2, normalized (-1, 1)
+	 */
+	float getMotor2Speed();
+
+	/**
+	 * @return number of rotations since reset
+	 */
+	float getRevolutions1();
+
+	/**
+	 * @return number of rotations since reset
+	 */
+	float getRevolutions2();
+
+	/**
+	 * @return battery voltage, volts
+	 */
+	float getBatteryVolts();
+
+	/**
+	 * @return motor 1 current, amps
+	 */
+	float getMotor1Current();
+
+	/**
+	 * @return motor 2 current, amps
+	 */
+	float getMotor2Current();
+
+	/**
+	 * @return the motor acceleration
+	 * controls motor speed change (1-10)
+	 * accel rate  | time for full fwd. to full rev.
+	 *  1          | 6.375 s
+	 *  2          | 1.6 s
+	 *  3          | 0.675 s
+	 *  5(default) | 1.275 s
+	 * 10          | 0.65 s
+	 */
+	uint8_t getMotorAccel();
+
+	/**
+	 * @return motor output mode
+	 * */
+	e_mode getMode();
+
+	/**
+	 * @return current command register value
+	 */
+	e_cmd getCommand();
+
+	/**
+	 * resets the encoders
+	 * @return non-zero -> error
+	 * */
+	int resetEncoders();
+
+	/**
+	 * enable/disable speed regulation
+	 * @return non-zero -> error
+	 */
+	int setSpeedRegulation(bool enable);
+
+	/**
+	 * set the timeout for the motors
+	 * enable/disable timeout (motor stop)
+	 * after 2 sec of no i2c messages
+	 * @return non-zero -> error
+	 */
+	int setTimeout(bool enable);
+
+	/**
+	 * sets the device address
+	 * can only be done with one MD25
+	 * on the bus
+	 * @return non-zero -> error
+	 */
+	int setDeviceAddress(uint8_t address);
+
+	/**
+	 * set motor 1 speed
+	 * @param normSpeed normalize speed between -1 and 1
+	 * @return non-zero -> error
+	*/
+	int setMotor1Speed(float normSpeed);
+
+	/**
+	 * set motor 2 speed
+	 * @param normSpeed normalize speed between -1 and 1
+	 * @return non-zero -> error
+	 */
+	int setMotor2Speed(float normSpeed);
+
+	/**
+	 * main update loop that updates MD25 motor
+	 * speeds based on actuator publication
+	 */
+	void update();
+
+	/**
+	 * probe for device
+	 */
+	virtual int probe();
+
+	/**
+	 * search for device
+	 */
+	int search();
+
+	/**
+	 * read data from i2c
+	 */
+	int readData();
+
+	/**
+	 * print status
+	 */
+	void status(char *string, size_t n);
+
+private:
+	/** poll structure for control packets */
+	struct pollfd _controlPoll;
+
+	/** actuator controls subscription */
+	control::UOrbSubscription<actuator_controls_s> _actuators;
+
+	// local copy of data from i2c device
+	uint8_t _version;
+	float _motor1Speed;
+	float _motor2Speed;
+	float _revolutions1;
+	float _revolutions2;
+	float _batteryVoltage;
+	float _motor1Current;
+	float _motor2Current;
+	uint8_t _motorAccel;
+	e_mode _mode;
+	e_cmd _command;
+
+	// private methods
+	int _writeUint8(uint8_t reg, uint8_t value);
+	int _writeInt8(uint8_t reg, int8_t value);
+	float _uint8ToNorm(uint8_t value);
+	uint8_t _normToUint8(float value);
+
+	/**
+	 * set motor control mode,
+	 * this driver assumed we are always in mode 0
+	 * so we don't let the user change the mode
+	 * @return non-zero -> error
+	 */
+	int _setMode(e_mode);
+};
+
+// unit testing
+int md25Test(const char *deviceName, uint8_t bus, uint8_t address);
+
+// vi:noet:smarttab:autoindent:ts=4:sw=4:tw=78

apps/drivers/md25/Makefile

+############################################################################
+#
+#   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name PX4 nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# 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 OWNER 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.
+#
+############################################################################
+
+#
+# MD25 I2C Based Motor Controller
+# http://www.robot-electronics.co.uk/htm/md25tech.htm
+#
+
+APPNAME		 = md25
+PRIORITY	 = SCHED_PRIORITY_DEFAULT
+STACKSIZE	 = 2048
+
+include $(APPDIR)/mk/app.mk

apps/drivers/md25/md25_main.cpp

+/****************************************************************************
+ *
+ *   Copyright (C) 2013 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * 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 OWNER 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.
+ *
+ ****************************************************************************/
+
+
+
+/**
+ * @ file md25.cpp
+ *
+ * Driver for MD25 I2C Motor Driver
+ *
+ * references:
+ * http://www.robot-electronics.co.uk/htm/md25tech.htm
+ * http://www.robot-electronics.co.uk/files/rpi_md25.c
+ *
+ */
+
+#include <nuttx/config.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>
+
+#include <systemlib/systemlib.h>
+#include <systemlib/param/param.h>
+
+#include <arch/board/board.h>
+#include "MD25.hpp"
+
+static bool thread_should_exit = false;     /**< Deamon exit flag */
+static bool thread_running = false;     /**< Deamon status flag */
+static int deamon_task;             /**< Handle of deamon task / thread */
+
+/**
+ * Deamon management function.
+ */
+extern "C" __EXPORT int md25_main(int argc, char *argv[]);
+
+/**
+ * Mainloop of deamon.
+ */
+int md25_thread_main(int argc, char *argv[]);
+
+/**
+ * Print the correct usage.
+ */
+static void usage(const char *reason);
+
+static void
+usage(const char *reason)
+{
+	if (reason)
+		fprintf(stderr, "%s\n", reason);
+
+	fprintf(stderr, "usage: md25 {start|stop|status|search|test|change_address}\n\n");
+	exit(1);
+}
+
+/**
+ * The deamon app only briefly exists to start
+ * the background job. The stack size assigned in the
+ * Makefile does only apply to this management task.
+ *
+ * The actual stack size should be set in the call
+ * to task_create().
+ */
+int md25_main(int argc, char *argv[])
+{
+
+	if (argc < 1)
+		usage("missing command");
+
+	if (!strcmp(argv[1], "start")) {
+
+		if (thread_running) {
+			printf("md25 already running\n");
+			/* this is not an error */
+			exit(0);
+		}
+
+		thread_should_exit = false;
+		deamon_task = task_spawn("md25",
+					 SCHED_DEFAULT,
+					 SCHED_PRIORITY_MAX - 10,
+					 2048,
+					 md25_thread_main,
+					 (const char **)argv);
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "test")) {
+
+		if (argc < 4) {
+			printf("usage: md25 test bus address\n");
+			exit(0);
+		}
+
+		const char *deviceName = "/dev/md25";
+
+		uint8_t bus = strtoul(argv[2], nullptr, 0);
+
+		uint8_t address = strtoul(argv[3], nullptr, 0);
+
+		md25Test(deviceName, bus, address);
+
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "probe")) {
+		if (argc < 4) {
+			printf("usage: md25 probe bus address\n");
+			exit(0);
+		}
+
+		const char *deviceName = "/dev/md25";
+
+		uint8_t bus = strtoul(argv[2], nullptr, 0);
+
+		uint8_t address = strtoul(argv[3], nullptr, 0);
+
+		MD25 md25(deviceName, bus, address);
+
+		int ret = md25.probe();
+
+		if (ret == OK) {
+			printf("MD25 found on bus %d at address 0x%X\n", bus, md25.get_address());
+
+		} else {
+			printf("MD25 not found on bus %d\n", bus);
+		}
+
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "search")) {
+		if (argc < 3) {
+			printf("usage: md25 search bus\n");
+			exit(0);
+		}
+
+		const char *deviceName = "/dev/md25";
+
+		uint8_t bus = strtoul(argv[2], nullptr, 0);
+
+		uint8_t address = strtoul(argv[3], nullptr, 0);
+
+		MD25 md25(deviceName, bus, address);
+
+		md25.search();
+
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "change_address")) {
+		if (argc < 5) {
+			printf("usage: md25 change_address bus old_address new_address\n");
+			exit(0);
+		}
+
+		const char *deviceName = "/dev/md25";
+
+		uint8_t bus = strtoul(argv[2], nullptr, 0);
+
+		uint8_t old_address = strtoul(argv[3], nullptr, 0);
+
+		uint8_t new_address = strtoul(argv[4], nullptr, 0);
+
+		MD25 md25(deviceName, bus, old_address);
+
+		int ret = md25.setDeviceAddress(new_address);
+
+		if (ret == OK)  {
+			printf("MD25 new address set to 0x%X\n", new_address);
+
+		} else {
+			printf("MD25 failed to set address to 0x%X\n", new_address);
+		}
+
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "stop")) {
+		thread_should_exit = true;
+		exit(0);
+	}
+
+	if (!strcmp(argv[1], "status")) {
+		if (thread_running) {
+			printf("\tmd25 app is running\n");
+
+		} else {
+			printf("\tmd25 app not started\n");
+		}
+
+		exit(0);
+	}
+
+	usage("unrecognized command");
+	exit(1);
+}
+
+int md25_thread_main(int argc, char *argv[])
+{
+	printf("[MD25] starting\n");
+
+	if (argc < 5) {
+		// extra md25 in arg list since this is a thread
+		printf("usage: md25 start bus address\n");
+		exit(0);
+	}
+
+	const char *deviceName = "/dev/md25";
+
+	uint8_t bus = strtoul(argv[3], nullptr, 0);
+
+	uint8_t address = strtoul(argv[4], nullptr, 0);
+
+	// start
+	MD25 md25("/dev/md25", bus, address);
+
+	thread_running = true;
+
+	// loop
+	while (!thread_should_exit) {
+		md25.update();
+	}
+
+	// exit
+	printf("[MD25] exiting.\n");
+	thread_running = false;
+	return 0;
+}
+
+// vi:noet:smarttab:autoindent:ts=4:sw=4:tw=78

nuttx/configs/px4fmu/nsh/appconfig

@@ -128,6 +128,7 @@ CONFIGURED_APPS += drivers/mkblctrl
 CONFIGURED_APPS += drivers/hil
 CONFIGURED_APPS += drivers/gps
 CONFIGURED_APPS += drivers/mb12xx
+CONFIGURED_APPS += drivers/md25
 
 # Testing stuff
 CONFIGURED_APPS += px4/sensors_bringup

nuttx/configs/px4fmu/nsh/defconfig

@@ -647,10 +647,14 @@ CONFIG_DISABLE_POLL=n
 # CONFIG_LIBC_FIXEDPRECISION - Sets 7 digits after dot for printing:
 #   5.1234567
 # CONFIG_HAVE_LONG_LONG - Enabled printf("%llu)
+# CONFIG_LIBC_STRERR - allow printing of error text
+# CONFIG_LIBC_STRERR_SHORT - allow printing of short error text
 #
 CONFIG_NOPRINTF_FIELDWIDTH=n
 CONFIG_LIBC_FLOATINGPOINT=y
 CONFIG_HAVE_LONG_LONG=y
+CONFIG_LIBC_STRERROR=n
+CONFIG_LIBC_STRERROR_SHORT=n
 
 #
 # Allow for architecture optimized implementations