Added LIS3DSH demo example

Author: marcorussi

examples/stm32/f4/stm32f4-discovery/lis3dsh_demo/Makefile

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+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2015 Marco Russi <[email protected]>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library 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 Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+BINARY = lis3dsh_demo
+
+LDSCRIPT = ../stm32f4-discovery.ld
+
+include ../../Makefile.include
+

examples/stm32/f4/stm32f4-discovery/lis3dsh_demo/README.md

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+# README
+
+This is a demo application for the 3-axis accelerometer LIS3DSH and the LEDs on the board using libopencm3.
+
+It's intended for the ST STM32F4DISCOVERY eval board. Rotating the board on each side will turn ON the closest LED to the side parallel to ground. Position the board with LED on top turns ON all the LEDs while facing the board on the ground turns them OFF.
+
+## Board connections
+
+*none required*

examples/stm32/f4/stm32f4-discovery/lis3dsh_demo/lis3dsh_demo.c

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+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2015 Marco Russi <[email protected]>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+
+/* ---------------- Inclusions ----------------- */
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/spi.h>
+
+
+
+
+/* ---------------- Local Defines ----------------- */
+
+/* LIS3DSH registers addresses */
+#define ADD_REG_WHO_AM_I				0x0F
+#define ADD_REG_CTRL_4					0x20
+#define ADD_REG_OUT_X_L					0x28
+#define ADD_REG_OUT_X_H					0x29
+#define ADD_REG_OUT_Y_L					0x2A
+#define ADD_REG_OUT_Y_H					0x2B
+#define ADD_REG_OUT_Z_L					0x2C
+#define ADD_REG_OUT_Z_H					0x2D
+
+/* WHO AM I register default value */
+#define UC_WHO_AM_I_DEFAULT_VALUE		0x3F
+
+/* ADD_REG_CTRL_4 register configuration value: X,Y,Z axis enabled and 400Hz of output data rate */
+#define UC_ADD_REG_CTRL_4_CFG_VALUE		0x77
+
+/* Sensitivity for 2G range [mg/digit] */
+#define SENS_2G_RANGE_MG_PER_DIGIT		((float)0.06)
+
+/* LED threshold value in mg */
+#define LED_TH_MG						(1000)	/* 1000mg (1G) */
+
+
+
+
+/* ---------------- Local Macros ----------------- */
+
+/* set read single command. Attention: command must be 0x3F at most */
+#define SET_READ_SINGLE_CMD(x)			(x | 0x80)
+/* set read multiple command. Attention: command must be 0x3F at most */
+#define SET_READ_MULTI_CMD(x)			(x | 0xC0)
+/* set write single command. Attention: command must be 0x3F at most */
+#define SET_WRITE_SINGLE_CMD(x)			(x & (~(0xC0)))
+/* set write multiple command. Attention: command must be 0x3F at most */
+#define SET_WRITE_MULTI_CMD(x)			(x & (~(0x80))	\
+										 x |= 0x40)
+
+/* Macros for turning LEDs ON */
+#define LED_GREEN_ON()					(gpio_set(GPIOD, GPIO12))
+#define LED_ORANGE_ON()					(gpio_set(GPIOD, GPIO13))
+#define LED_RED_ON()					(gpio_set(GPIOD, GPIO14))
+#define LED_BLUE_ON()					(gpio_set(GPIOD, GPIO15))
+
+/* Macros for turning LEDs OFF */
+#define LED_GREEN_OFF()					(gpio_clear(GPIOD, GPIO12))
+#define LED_ORANGE_OFF()				(gpio_clear(GPIOD, GPIO13))
+#define LED_RED_OFF()					(gpio_clear(GPIOD, GPIO14))
+#define LED_BLUE_OFF()					(gpio_clear(GPIOD, GPIO15))
+
+
+
+
+/* ------------- Local functions prototypes --------------- */
+
+static void			gpio_setup			(void);
+static void 		spi_setup			(void);
+static void 		LIS3DSH_init		(void);
+static void 		LIS3DSH_write_reg	(int, int);
+static int 			LIS3DSH_read_reg	(int);
+static inline int 	twoComplToInt16		(int);
+
+
+
+
+/* ------------ Local functions implementation ----------- */
+
+/* Function to setup all used GPIOs */
+static void gpio_setup(void)
+{
+	/* Enable GPIOD clock. */
+	rcc_periph_clock_enable(RCC_GPIOD);
+
+	/* Set GPIO12, GPIO13, GPIO14, GPIO15 (in GPIO port D) to 'output push-pull'. */
+	gpio_mode_setup(GPIOD, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO12 | GPIO13 | GPIO14 | GPIO15);
+
+	/* LIS3DSH pins map:
+	PA5 - SPI1_SCK
+	PA6 - SPI1_MISO
+	PA7 - SPI1_MOSI
+	PE3 - CS_SPI
+	*/
+
+	/* Enable GPIOA clock. */
+	rcc_periph_clock_enable(RCC_GPIOA);
+	/* set SPI pins as CLK, MOSI, MISO */
+	gpio_mode_setup(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO5 | GPIO6 | GPIO7);
+	/* Push Pull, Speed 100 MHz */
+	gpio_set_output_options(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_100MHZ, GPIO5 | GPIO6 | GPIO7);
+	/* Alternate Function: SPI1 */
+	gpio_set_af(GPIOA, GPIO_AF5, GPIO5 | GPIO6 | GPIO7);
+
+	/* Enable GPIOE clock. */
+	rcc_periph_clock_enable(RCC_GPIOE);
+	/* set CS as OUTPUT */
+	gpio_mode_setup(GPIOE, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO3);
+	/* Push Pull, Speed 100 MHz */
+	gpio_set_output_options(GPIOE, GPIO_OTYPE_PP, GPIO_OSPEED_100MHZ, GPIO3);
+	/* set CS high */
+	gpio_set(GPIOE, GPIO3);
+}
+
+
+/* Function to setup the SPI1 */
+static void spi_setup(void)
+{
+	/* Enable SPI1 clock. */
+	rcc_periph_clock_enable(RCC_SPI1);
+
+	/* reset SPI1 */
+	spi_reset(SPI1);
+	/* init SPI1 master */
+	spi_init_master(SPI1,
+					SPI_CR1_BAUDRATE_FPCLK_DIV_64,
+					SPI_CR1_CPOL_CLK_TO_0_WHEN_IDLE,
+					SPI_CR1_CPHA_CLK_TRANSITION_1,
+					SPI_CR1_DFF_8BIT,
+					SPI_CR1_MSBFIRST);
+	/* enable SPI1 first */
+	spi_enable(SPI1);
+}
+
+
+/* Function to initialise the LIS3DSH */
+static void LIS3DSH_init(void)
+{
+	int intRegValue;
+
+	/* init SPI1 */
+	spi_setup();
+
+	/* get WHO AM I value */
+	intRegValue = LIS3DSH_read_reg(ADD_REG_WHO_AM_I);
+
+	/* if WHO AM I value is the expected one */
+	if( intRegValue == UC_WHO_AM_I_DEFAULT_VALUE )
+	{
+		/* set output data rate to 400 Hz and enable X,Y,Z axis */
+		LIS3DSH_write_reg(ADD_REG_CTRL_4, UC_ADD_REG_CTRL_4_CFG_VALUE);
+		/* verify written value */
+		intRegValue = LIS3DSH_read_reg(ADD_REG_CTRL_4);
+		/* if written value is different */
+		if( intRegValue != UC_ADD_REG_CTRL_4_CFG_VALUE )
+		{
+			/* ERROR: stay here... */
+			while(1);
+		}
+	}
+	else
+	{
+		/* ERROR: stay here... */
+		while(1);
+	}
+}
+
+
+/* Function to write a register to LIS3DSH through SPI  */
+static void LIS3DSH_write_reg(int reg, int data)
+{
+	/* set CS low */
+	gpio_clear(GPIOE, GPIO3);
+	/* discard returned value */
+	spi_xfer(SPI1, SET_WRITE_SINGLE_CMD(reg));
+	spi_xfer(SPI1, data);
+	/* set CS high */
+	gpio_set(GPIOE, GPIO3);
+}
+
+
+/* Function to read a register from LIS3DSH through SPI */
+static int LIS3DSH_read_reg(int reg)
+{
+	int regValue;
+	/* set CS low */
+	gpio_clear(GPIOE, GPIO3);
+	regValue = spi_xfer(SPI1, SET_READ_SINGLE_CMD(reg));
+	regValue = spi_xfer(SPI1, 0xFF);
+	/* set CS high */
+	gpio_set(GPIOE, GPIO3);
+
+	return regValue;
+}
+
+
+/* Transform a two's complement value to 16-bit int value */
+static inline int twoComplToInt16(int twoComplValue)
+{
+	int int16Value = 0;
+
+	/* conversion */
+	if(twoComplValue > 32768)
+	{
+		int16Value = -(((~twoComplValue) & 0xFFFF) + 1);
+	}
+	else
+	{
+		int16Value = twoComplValue;
+	}
+
+	return int16Value;
+}
+
+
+/* Main function */
+int main(void)
+{
+	int i;
+	int intValueMgX, intValueMgY, intValueMgZ;
+
+	/* setup all GPIOs */
+	gpio_setup();
+
+	/* initialise LIS3DSH */
+	LIS3DSH_init();
+
+	/* infinite loop */
+	while(1)
+	{
+		/* get X, Y, Z values */
+		intValueMgX = ((LIS3DSH_read_reg(ADD_REG_OUT_X_H) << 8) | LIS3DSH_read_reg(ADD_REG_OUT_X_L));
+		intValueMgY = ((LIS3DSH_read_reg(ADD_REG_OUT_Y_H) << 8) | LIS3DSH_read_reg(ADD_REG_OUT_Y_L));
+		intValueMgZ = ((LIS3DSH_read_reg(ADD_REG_OUT_Z_H) << 8) | LIS3DSH_read_reg(ADD_REG_OUT_Z_L));
+
+		/* transform X value from two's complement to 16-bit int */
+		intValueMgX = twoComplToInt16(intValueMgX);
+		/* convert X absolute value to mg value */
+		intValueMgX = intValueMgX * SENS_2G_RANGE_MG_PER_DIGIT;
+
+		/* transform Y value from two's complement to 16-bit int */
+		intValueMgY = twoComplToInt16(intValueMgY);
+		/* convert Y absolute value to mg value */
+		intValueMgY = intValueMgY * SENS_2G_RANGE_MG_PER_DIGIT;
+
+		/* transform Z value from two's complement to 16-bit int */
+		intValueMgZ = twoComplToInt16(intValueMgZ);
+		/* convert Z absolute value to mg value */
+		intValueMgZ = intValueMgZ * SENS_2G_RANGE_MG_PER_DIGIT;
+
+		/* set X related LEDs according to specified threshold */
+		if(intValueMgX >= LED_TH_MG)
+		{
+			LED_BLUE_OFF();
+			LED_ORANGE_OFF();
+			LED_GREEN_OFF();
+			LED_RED_ON();
+		}
+		else if(intValueMgX <= -LED_TH_MG)
+		{
+			LED_BLUE_OFF();
+			LED_ORANGE_OFF();
+			LED_RED_OFF();
+			LED_GREEN_ON();
+		}
+
+		/* set Y related LEDs according to specified threshold */
+		if(intValueMgY >= LED_TH_MG)
+		{
+			LED_BLUE_OFF();
+			LED_RED_OFF();
+			LED_GREEN_OFF();
+			LED_ORANGE_ON();
+		}
+		else if(intValueMgY <= -LED_TH_MG)
+		{
+			LED_RED_OFF();
+			LED_GREEN_OFF();
+			LED_ORANGE_OFF();
+			LED_BLUE_ON();
+		}
+
+		/* set Z related LEDs according to specified threshold */
+		if(intValueMgZ >= LED_TH_MG)
+		{
+			LED_BLUE_ON();
+			LED_ORANGE_ON();
+			LED_RED_ON();
+			LED_GREEN_ON();
+		}
+		else if(intValueMgZ <= -LED_TH_MG)
+		{
+			LED_BLUE_OFF();
+			LED_ORANGE_OFF();
+			LED_RED_OFF();
+			LED_GREEN_OFF();
+		}
+
+		/* Wait a bit... */
+		for (i = 0; i < 100; i++)
+		{
+			__asm__("nop");
+		}
+	}
+
+	return 0;
+}
+
+
+/* End of file */