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139 lines
3.8 KiB
C
139 lines
3.8 KiB
C
/*
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* srf02-ultrasonic-sensor.c - Driver for the SRF02 ultrasonic.
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*
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* Copyright (C) 2013 Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
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*
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* This source code is licensed under the LGPLv2 license,
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* See the file LICENSE for more details.
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*/
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/**
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* @file
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* @internal
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* @brief Driver for the SRF02 ultrasonic ranger.
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* The connection between the MCU and the SRF08 is based on the
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* i2c-interface.
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*
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* @author Zakaria Kasmi <zkasmi@inf.fu-berlin.de>
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* @version $Revision: 3856 $
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*
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* @note $Id: srf02-ultrasonic-sensor.c 3857 2013-09-24 17:39:33 kasmi $
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*
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*/
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#include <stdbool.h>
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#include <stdint.h>
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#include <stdio.h>
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#include "msg.h"
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#include "vtimer.h"
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#include "timex.h"
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#include "thread.h"
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#include "hwtimer.h"
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#include "srf02-ultrasonic-sensor.h"
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#include "i2c.h"
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bool srf02_init(uint8_t i2c_interface, uint32_t baud_rate)
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{
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if (i2c_initialize(i2c_interface, (uint32_t) I2CMASTER, 0, baud_rate, NULL)
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== false) { /* initialize I2C */
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puts("fatal error happened in i2c_initialize()\n");
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return false;
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}
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else {
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i2c_enable_pull_up_resistor(i2c_interface);
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//i2c_disable_pull_up_resistor(i2c_interface);
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return true;
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}
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}
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uint32_t srf02_get_distance(uint8_t ranging_mode)
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{
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bool status = false;
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uint8_t reg_size = 1;
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uint8_t range_high_byte = 0;
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uint8_t range_low_byte = 0;
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uint8_t rx_buff[reg_size];
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uint8_t tx_buff[reg_size];
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uint32_t distance = 0;
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tx_buff[0] = ranging_mode;
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status = i2c_write(SRF02_I2C_INTERFACE, SRF02_DEFAULT_ADDR,
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SRF02_COMMAND_REG, tx_buff, reg_size);
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if (!status) {
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puts("Write the ranging command to the i2c-interface is failed");
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distance = UINT32_MAX;
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return distance;
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}
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hwtimer_wait(HWTIMER_TICKS(65000));
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status = i2c_read(SRF02_I2C_INTERFACE, SRF02_DEFAULT_ADDR,
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SRF02_RANGE_HIGH_BYTE, rx_buff, reg_size);
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if (!status) {
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puts("Read the high echo byte from the i2c-interface is failed");
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distance = UINT32_MAX;
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return distance;
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}
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range_high_byte = rx_buff[0];
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status = i2c_read(SRF02_I2C_INTERFACE, SRF02_DEFAULT_ADDR,
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SRF02_RANGE_LOW_BYTE, rx_buff, reg_size);
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if (!status) {
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puts("Read the low echo byte from the i2c-interface is failed");
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distance = UINT32_MAX;
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return distance;
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}
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range_low_byte = rx_buff[0];
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distance = (range_high_byte << 8) | range_low_byte;
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//printf("%u | %u\n", range_high_byte, range_low_byte);
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return distance;
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}
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void srf02_start_ranging(uint16_t ranging_mode)
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{
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uint32_t distance = 0;
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while (1) {
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distance = srf02_get_distance(ranging_mode);
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if (distance != UINT32_MAX) {
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switch (ranging_mode) {
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case SRF02_REAL_RANGING_MODE_CM :
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printf("distance = %lu cm\n", distance);
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break;
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case SRF02_REAL_RANGING_MODE_INCH :
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printf("distance = %lu inch\n", distance);
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break;
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case SRF02_REAL_RANGING_MODE_MICRO_SEC:
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// dist_m = 0.000172 distance_micro_sec (air)
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printf("distance = %lu micro_sec\n", distance);
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break;
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case SRF02_FAKE_RANGING_MODE_CM:
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case SRF02_FAKE_RANGING_MODE_INCH:
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case SRF02_FAKE_RANGING_MODE_MICRO_SEC:
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printf("distance fake ranging = %lu \n", distance);
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break;
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default:
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printf("distance = %lu cm\n", distance);
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}
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hwtimer_wait(HWTIMER_TICKS(50000));
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}
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else {
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break;
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}
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}
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puts("The SRF02 range sampling is ended!!");
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}
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