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Library to work with the LDC1000 from Texas Instruments

Dependencies:   FastPWM

Dependents:   LDC1000_test

LDC1000

This library was written to interface to Texas Instruments' LDC1000 in order to perform inductance measurement. This libary needs a SPI peripheral on your mbed device to talk to the LDC1000.

Clock

The LDC1000 needs a high speed clock for its internal frequency counter. In order to provide this clock, the FastPWM library is used. This may change the behaviour of other PWM channels, please be aware of that, and read the FastPWM documentation to understand the implications.

Unsupported

Not supported (yet):

  1. Setting the RpMAX and RpMIN values
  2. Setting the interrupt pin functionality

LDC1000.cpp@5:98d4fd07734a, 2015-05-26 (annotated)

Committer:
hamid567
Date:
Tue May 26 14:34:05 2015 +0000
Revision:
5:98d4fd07734a
Parent:
4:62ebb87678f8
Child:
6:5b6ad98d6436
Set mode to standby before writing registers. Counter 1..0 not changing ?

Who changed what in which revision?

UserRevisionLine numberNew contents of line
vsluiter 0:90873b4e8330 1 /**
vsluiter 0:90873b4e8330 2 * @file LDC1000.h
vsluiter 0:90873b4e8330 3 * @brief this C++ file wcontains all required
vsluiter 0:90873b4e8330 4 * functions to interface with Texas
vsluiter 0:90873b4e8330 5 * Instruments' LDC1000.
vsluiter 0:90873b4e8330 6 *
vsluiter 0:90873b4e8330 7 * @author Victor Sluiter
vsluiter 0:90873b4e8330 8 *
vsluiter 0:90873b4e8330 9 * @date 2015-04-01
vsluiter 0:90873b4e8330 10 */
vsluiter 0:90873b4e8330 11
vsluiter 0:90873b4e8330 12 #include "LDC1000.h"
vsluiter 0:90873b4e8330 13
hamid567 4:62ebb87678f8 14 LDC1000::LDC1000(PinName mosi, PinName miso, PinName sck, PinName cs, float capacitor, float f_external, PinName clock_out) : _spiport(mosi,miso,sck,NC), _cs_pin(cs), _clock(clock_out,1)
vsluiter 0:90873b4e8330 15 {
vsluiter 0:90873b4e8330 16 cap = capacitor;
vsluiter 0:90873b4e8330 17 _spiport.format(8,3);
vsluiter 0:90873b4e8330 18 _spiport.frequency(1E6);
vsluiter 0:90873b4e8330 19 _cs_pin.write(1);
hamid567 1:a88df80e7664 20 wait_us(100);
hamid567 5:98d4fd07734a 21 mode(LDC_MODE_STANDBY);
hamid567 5:98d4fd07734a 22 setFrequency(f_external);
hamid567 5:98d4fd07734a 23 wait(0.1);
hamid567 5:98d4fd07734a 24 setOutputPower(LDC_AMPLITUDE_4V);
hamid567 1:a88df80e7664 25 wait_us(10);
vsluiter 0:90873b4e8330 26 setResponseTime(LDC_RESPONSE_384);
hamid567 2:44b76f6f19d5 27 setWatchdog(5000);
hamid567 5:98d4fd07734a 28
hamid567 5:98d4fd07734a 29 // Write comando's like in EVM start log:
hamid567 5:98d4fd07734a 30 /* writeSPIregister(0x0B,0x00);
hamid567 5:98d4fd07734a 31 writeSPIregister(0x01,0x0E);
hamid567 5:98d4fd07734a 32 writeSPIregister(0x02,0x3C);
hamid567 5:98d4fd07734a 33 writeSPIregister(0x03,0x15);
hamid567 5:98d4fd07734a 34 writeSPIregister(0x04,0x17);
hamid567 5:98d4fd07734a 35 writeSPIregister(0x05,0x00);
hamid567 5:98d4fd07734a 36 writeSPIregister(0x06,0x50);
hamid567 5:98d4fd07734a 37 writeSPIregister(0x07,0x14);
hamid567 5:98d4fd07734a 38 writeSPIregister(0x08,0xC0);
hamid567 5:98d4fd07734a 39 writeSPIregister(0x09,0x12);
hamid567 5:98d4fd07734a 40 writeSPIregister(0x0A,0x04);
hamid567 5:98d4fd07734a 41 // writeSPIregister(0x0C,0x01);
hamid567 5:98d4fd07734a 42 writeSPIregister(0x0B,0x01);*/
hamid567 5:98d4fd07734a 43
hamid567 5:98d4fd07734a 44 mode(LDC_MODE_ACTIVE);
vsluiter 0:90873b4e8330 45 }
vsluiter 0:90873b4e8330 46
vsluiter 0:90873b4e8330 47 void LDC1000::setOutputPower(LDC_AMPLITUDE amplitude)
vsluiter 0:90873b4e8330 48 {
vsluiter 0:90873b4e8330 49 uint8_t buffer;
vsluiter 0:90873b4e8330 50 _amplitude = amplitude;
vsluiter 0:90873b4e8330 51 readSPI(&buffer, 0x04);
vsluiter 0:90873b4e8330 52 buffer &= 0xE7; //clear amplitude bits
vsluiter 0:90873b4e8330 53 buffer |= (amplitude<<3) & 0xE7;
vsluiter 0:90873b4e8330 54 writeSPI(&buffer,0x04);
vsluiter 0:90873b4e8330 55
vsluiter 0:90873b4e8330 56 }
vsluiter 0:90873b4e8330 57
hamid567 2:44b76f6f19d5 58 void LDC1000::setWatchdog(float frequency)
hamid567 2:44b76f6f19d5 59 {
hamid567 2:44b76f6f19d5 60 uint8_t buffer;
hamid567 2:44b76f6f19d5 61 buffer = 68.94*log(frequency/2500);
hamid567 2:44b76f6f19d5 62 writeSPI(&buffer,0x03);
hamid567 1:a88df80e7664 63
hamid567 2:44b76f6f19d5 64 }
hamid567 1:a88df80e7664 65
vsluiter 0:90873b4e8330 66 void LDC1000::setResponseTime(LDC_RESPONSE responsetime)
vsluiter 0:90873b4e8330 67 {
vsluiter 0:90873b4e8330 68 uint8_t buffer;
vsluiter 0:90873b4e8330 69 _responsetime = responsetime;
vsluiter 0:90873b4e8330 70 readSPI(&buffer, 0x04);
vsluiter 0:90873b4e8330 71 buffer &= 0xF8; //clear responsetime bits
hamid567 5:98d4fd07734a 72 buffer |= responsetime & 0x07;
vsluiter 0:90873b4e8330 73 writeSPI(&buffer,0x04);
vsluiter 0:90873b4e8330 74 }
vsluiter 0:90873b4e8330 75
vsluiter 0:90873b4e8330 76 void LDC1000::setFrequency(float frequency)
vsluiter 0:90873b4e8330 77 {
vsluiter 0:90873b4e8330 78 _frequency = frequency;
vsluiter 0:90873b4e8330 79 _clock.period(1.0/frequency);
hamid567 4:62ebb87678f8 80 _clock.pulsewidth(0.5/frequency);
vsluiter 0:90873b4e8330 81 }
vsluiter 0:90873b4e8330 82
vsluiter 0:90873b4e8330 83 float LDC1000::getInductance()
vsluiter 0:90873b4e8330 84 {
vsluiter 0:90873b4e8330 85 uint16_t resp[] = {192, 384, 768, 1536, 3072, 6144};
vsluiter 0:90873b4e8330 86 _raw_l = readRawCounts();
vsluiter 0:90873b4e8330 87 _fsensor = (_frequency/(_raw_l*3.0))*resp[(uint8_t)(_responsetime)];
hamid567 2:44b76f6f19d5 88 return 1./(cap*pow(2*PI*_fsensor,2));
vsluiter 0:90873b4e8330 89 };
vsluiter 0:90873b4e8330 90
vsluiter 0:90873b4e8330 91 uint32_t LDC1000::readRawCounts(void)
vsluiter 0:90873b4e8330 92 {
vsluiter 0:90873b4e8330 93 union
vsluiter 0:90873b4e8330 94 {
vsluiter 0:90873b4e8330 95 uint8_t buf[4];
vsluiter 0:90873b4e8330 96 uint32_t value;
vsluiter 0:90873b4e8330 97 } val;
vsluiter 0:90873b4e8330 98 val.value = 0;
vsluiter 0:90873b4e8330 99 readSPI(val.buf,0x23,3);
vsluiter 0:90873b4e8330 100 return val.value;
vsluiter 0:90873b4e8330 101 }
vsluiter 0:90873b4e8330 102
hamid567 5:98d4fd07734a 103
hamid567 5:98d4fd07734a 104
vsluiter 0:90873b4e8330 105 void LDC1000::readSPI(uint8_t *data, uint8_t address, uint8_t num_bytes)
vsluiter 0:90873b4e8330 106 {
vsluiter 0:90873b4e8330 107 _cs_pin.write(0);
vsluiter 0:90873b4e8330 108 _spiport.write(address | 0x80); //read flag
vsluiter 0:90873b4e8330 109 for(int i=0; i < num_bytes ; i++)
vsluiter 0:90873b4e8330 110 {
hamid567 1:a88df80e7664 111 data[i] = _spiport.write(0xFF);
vsluiter 0:90873b4e8330 112 }
vsluiter 0:90873b4e8330 113 _cs_pin.write(1);
vsluiter 0:90873b4e8330 114 }
vsluiter 0:90873b4e8330 115
vsluiter 0:90873b4e8330 116 void LDC1000::writeSPI(uint8_t *data, uint8_t address, uint8_t num_bytes)
vsluiter 0:90873b4e8330 117 {
vsluiter 0:90873b4e8330 118 _cs_pin.write(0);
vsluiter 0:90873b4e8330 119 _spiport.write(address);
vsluiter 0:90873b4e8330 120 for(int i=0; i < num_bytes ; i++)
vsluiter 0:90873b4e8330 121 {
hamid567 1:a88df80e7664 122 _spiport.write(data[i]);
vsluiter 0:90873b4e8330 123 }
vsluiter 0:90873b4e8330 124 _cs_pin.write(1);
vsluiter 0:90873b4e8330 125 }