Greg Steiert / maxim_dev

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Dependents:   sensomed

features/unsupported/tests/peripherals/SRF08/SRF08.cpp@0:0e018d759a2a, 2016-11-08 (annotated)

Committer:
switches
Date:
Tue Nov 08 18:27:11 2016 +0000
Revision:
0:0e018d759a2a
Initial commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
switches 0:0e018d759a2a 1
switches 0:0e018d759a2a 2 /*
switches 0:0e018d759a2a 3 Copyright (c) 2010 Chris Styles ( chris dot styles at mbed dot org )
switches 0:0e018d759a2a 4
switches 0:0e018d759a2a 5 Permission is hereby granted, free of charge, to any person obtaining a copy
switches 0:0e018d759a2a 6 of this software and associated documentation files (the "Software"), to deal
switches 0:0e018d759a2a 7 in the Software without restriction, including without limitation the rights
switches 0:0e018d759a2a 8 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
switches 0:0e018d759a2a 9 copies of the Software, and to permit persons to whom the Software is
switches 0:0e018d759a2a 10 furnished to do so, subject to the following conditions:
switches 0:0e018d759a2a 11
switches 0:0e018d759a2a 12 The above copyright notice and this permission notice shall be included in
switches 0:0e018d759a2a 13 all copies or substantial portions of the Software.
switches 0:0e018d759a2a 14
switches 0:0e018d759a2a 15 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
switches 0:0e018d759a2a 16 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
switches 0:0e018d759a2a 17 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
switches 0:0e018d759a2a 18 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
switches 0:0e018d759a2a 19 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
switches 0:0e018d759a2a 20 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
switches 0:0e018d759a2a 21 THE SOFTWARE.
switches 0:0e018d759a2a 22 */
switches 0:0e018d759a2a 23
switches 0:0e018d759a2a 24 #include "SRF08.h"
switches 0:0e018d759a2a 25
switches 0:0e018d759a2a 26
switches 0:0e018d759a2a 27 SRF08::SRF08(PinName sda, PinName scl, int addr) : m_i2c(sda, scl), m_addr(addr) {
switches 0:0e018d759a2a 28 char cmd[2];
switches 0:0e018d759a2a 29
switches 0:0e018d759a2a 30 // Set up SRF08 max range and receiver sensitivity over I2C bus
switches 0:0e018d759a2a 31 cmd[0] = 0x02; // Range register
switches 0:0e018d759a2a 32 cmd[1] = 0x1C; // Set max range about 100cm
switches 0:0e018d759a2a 33 m_i2c.write(m_addr, cmd, 2);
switches 0:0e018d759a2a 34 cmd[0] = 0x01; // Receiver gain register
switches 0:0e018d759a2a 35 cmd[1] = 0x1B; // Set max receiver gain
switches 0:0e018d759a2a 36 m_i2c.write(m_addr, cmd, 2);
switches 0:0e018d759a2a 37
switches 0:0e018d759a2a 38 }
switches 0:0e018d759a2a 39
switches 0:0e018d759a2a 40 SRF08::~SRF08() {
switches 0:0e018d759a2a 41
switches 0:0e018d759a2a 42 }
switches 0:0e018d759a2a 43
switches 0:0e018d759a2a 44 float SRF08::read() {
switches 0:0e018d759a2a 45
switches 0:0e018d759a2a 46 char cmd[2];
switches 0:0e018d759a2a 47 char echo[2];
switches 0:0e018d759a2a 48
switches 0:0e018d759a2a 49
switches 0:0e018d759a2a 50 // Get range data from SRF08
switches 0:0e018d759a2a 51 // Send Tx burst command over I2C bus
switches 0:0e018d759a2a 52 cmd[0] = 0x00; // Command register
switches 0:0e018d759a2a 53 cmd[1] = 0x51; // Ranging results in cm
switches 0:0e018d759a2a 54 m_i2c.write(m_addr, cmd, 2); // Send ranging burst
switches 0:0e018d759a2a 55
switches 0:0e018d759a2a 56 wait(0.07); // Wait for return echo
switches 0:0e018d759a2a 57
switches 0:0e018d759a2a 58 // Read back range over I2C bus
switches 0:0e018d759a2a 59 cmd[0] = 0x02; // Address of first echo
switches 0:0e018d759a2a 60 m_i2c.write(m_addr, cmd, 1, 1); // Send address of first echo
switches 0:0e018d759a2a 61 m_i2c.read(m_addr, echo, 2); // Read two-byte echo result
switches 0:0e018d759a2a 62
switches 0:0e018d759a2a 63 // Generate PWM mark/space ratio from range data
switches 0:0e018d759a2a 64 float range = (echo[0]<<8)+echo[1];
switches 0:0e018d759a2a 65
switches 0:0e018d759a2a 66 return range;
switches 0:0e018d759a2a 67 }