Gerrit Pathuis / Mbed 2 deprecated K22F_AS5510_I2C_tst

AS5510, 10 bit Absolute linear Hall Field Sensor with I2C output. Lateral movement measurement for simple 2-pole magnet. Magnet diameter 1mm, length 2mm. Output 10 bit resolution, distance per LSB is 2.0mm/1024, ADC sampling frequency 50 kHz.

Dependencies:   mbed

main.cpp@0:de08120b71bd, 2015-05-30 (annotated)

Committer:
GerritPathuis
Date:
Sat May 30 18:02:46 2015 +0000
Revision:
0:de08120b71bd
Child:
1:79e6ae3a23d8
Best result so far

Who changed what in which revision?

UserRevisionLine numberNew contents of line
GerritPathuis 0:de08120b71bd 1 #include "mbed.h"
GerritPathuis 0:de08120b71bd 2 #define TRUE 1
GerritPathuis 0:de08120b71bd 3 #define FALSE 0
GerritPathuis 0:de08120b71bd 4
GerritPathuis 0:de08120b71bd 5 //////////////////////////////////////////////////
GerritPathuis 0:de08120b71bd 6 // Testing AS5510 sensor with K22F //
GerritPathuis 0:de08120b71bd 7 // //
GerritPathuis 0:de08120b71bd 8 // Test at 100kHz //
GerritPathuis 0:de08120b71bd 9 // I2C address 0x1C used by FXOS8700CQ //
GerritPathuis 0:de08120b71bd 10 // 3-axis accelerometer and 3-axis magetometer //
GerritPathuis 0:de08120b71bd 11 //////////////////////////////////////////////////
GerritPathuis 0:de08120b71bd 12 Serial pc(USBTX, USBRX); // tx, rx
GerritPathuis 0:de08120b71bd 13 DigitalOut led_red(LED_RED); //
GerritPathuis 0:de08120b71bd 14 DigitalOut led_green(LED_GREEN); //
GerritPathuis 0:de08120b71bd 15 I2C i2c(PTB3, PTB2); // SDA, SCL (for K22F)
GerritPathuis 0:de08120b71bd 16
GerritPathuis 0:de08120b71bd 17 const int i2c_slave_addr1 = 0x56; // sensor AS5510 number 1 (7 bits), 0x56 or 0x57
GerritPathuis 0:de08120b71bd 18
GerritPathuis 0:de08120b71bd 19 //--- public functions---
GerritPathuis 0:de08120b71bd 20 void init_as5510(void);
GerritPathuis 0:de08120b71bd 21 void read_field(void);
GerritPathuis 0:de08120b71bd 22 int offset_comp(void);
GerritPathuis 0:de08120b71bd 23 void look_for_hardware_i2c(void);
GerritPathuis 0:de08120b71bd 24
GerritPathuis 0:de08120b71bd 25
GerritPathuis 0:de08120b71bd 26 int main()
GerritPathuis 0:de08120b71bd 27 {
GerritPathuis 0:de08120b71bd 28 int done=0;
GerritPathuis 0:de08120b71bd 29
GerritPathuis 0:de08120b71bd 30 i2c.frequency(400 * 1000); // 0.1/0.4/1.0 mHz
GerritPathuis 0:de08120b71bd 31 wait_ms(2); // power up wait
GerritPathuis 0:de08120b71bd 32
GerritPathuis 0:de08120b71bd 33
GerritPathuis 0:de08120b71bd 34 //look_for_hardware_i2c(); // Harware present ?
GerritPathuis 0:de08120b71bd 35 init_as5510();
GerritPathuis 0:de08120b71bd 36 //----------Setup register----------------------
GerritPathuis 0:de08120b71bd 37 while (done != 1)
GerritPathuis 0:de08120b71bd 38 done= offset_comp(); // Only one time required
GerritPathuis 0:de08120b71bd 39 while (true)
GerritPathuis 0:de08120b71bd 40 if (done == 1) read_field(); //----------Read magnetic Field-----------------
GerritPathuis 0:de08120b71bd 41 }
GerritPathuis 0:de08120b71bd 42
GerritPathuis 0:de08120b71bd 43
GerritPathuis 0:de08120b71bd 44 void look_for_hardware_i2c()
GerritPathuis 0:de08120b71bd 45 {
GerritPathuis 0:de08120b71bd 46 pc.printf("\r\n\n\n");
GerritPathuis 0:de08120b71bd 47 pc.printf("Note I2C address 0x1C used by FXOS8700CQ 3-axis accelerometer and 3-axis magetometer\r\n");
GerritPathuis 0:de08120b71bd 48 pc.printf("Start hardware search..... \r\n");
GerritPathuis 0:de08120b71bd 49
GerritPathuis 0:de08120b71bd 50 int count = 0;
GerritPathuis 0:de08120b71bd 51 for (int address=12; address<256; address+=2) {
GerritPathuis 0:de08120b71bd 52 if (!i2c.write(address, NULL, 0)) { // 0 returned is ok
GerritPathuis 0:de08120b71bd 53 pc.printf(" - I2C device found at address 0x%02X\n\r", address >>1);
GerritPathuis 0:de08120b71bd 54 count++;
GerritPathuis 0:de08120b71bd 55 }
GerritPathuis 0:de08120b71bd 56 }
GerritPathuis 0:de08120b71bd 57 pc.printf("%d devices found \n\r", count);
GerritPathuis 0:de08120b71bd 58 }
GerritPathuis 0:de08120b71bd 59
GerritPathuis 0:de08120b71bd 60 void init_as5510()
GerritPathuis 0:de08120b71bd 61 {
GerritPathuis 0:de08120b71bd 62 int i2c_adrs=0;
GerritPathuis 0:de08120b71bd 63 char idata[2];
GerritPathuis 0:de08120b71bd 64 int result=0;
GerritPathuis 0:de08120b71bd 65
GerritPathuis 0:de08120b71bd 66 pc.printf("\r\n");
GerritPathuis 0:de08120b71bd 67 pc.printf("Start AS5510 init.. \r\n");
GerritPathuis 0:de08120b71bd 68
GerritPathuis 0:de08120b71bd 69 i2c_adrs= (i2c_slave_addr1 << 1); // AS5510 Slave address lsb= 0 for write
GerritPathuis 0:de08120b71bd 70 //---------------------------------------------------------------------------
GerritPathuis 0:de08120b71bd 71 idata[0]=0x0B; // Register for Sensitivity
GerritPathuis 0:de08120b71bd 72 idata[1]=0x00; // byte
GerritPathuis 0:de08120b71bd 73 result= i2c.write(i2c_adrs, idata, 2, 0); // Now write_sensitivity
GerritPathuis 0:de08120b71bd 74 if (result != 0) pc.printf("No ACK bit! (09)\n\r");
GerritPathuis 0:de08120b71bd 75
GerritPathuis 0:de08120b71bd 76 //------------------------------------------------------------------------------------------
GerritPathuis 0:de08120b71bd 77 idata[0]=0x02; // 0x02 address setup register for operation, speed, polarity
GerritPathuis 0:de08120b71bd 78 idata[1]=0x04; // Normal Operation, Slow mode (1), NORMAL Polarity (0), Power Up (0)
GerritPathuis 0:de08120b71bd 79 result= i2c.write(i2c_adrs, idata, 2, 0); // Now write_operation
GerritPathuis 0:de08120b71bd 80 if (result != 0) pc.printf("No ACK bit! (11)\n\r");
GerritPathuis 0:de08120b71bd 81
GerritPathuis 0:de08120b71bd 82 pc.printf("AS5510 init done\r\n");
GerritPathuis 0:de08120b71bd 83 }
GerritPathuis 0:de08120b71bd 84
GerritPathuis 0:de08120b71bd 85
GerritPathuis 0:de08120b71bd 86 int offset_comp(void)
GerritPathuis 0:de08120b71bd 87 {
GerritPathuis 0:de08120b71bd 88 int adrss=0;
GerritPathuis 0:de08120b71bd 89 int oresult=0;
GerritPathuis 0:de08120b71bd 90 char off_data[2];
GerritPathuis 0:de08120b71bd 91 int ocf_done=0;
GerritPathuis 0:de08120b71bd 92
GerritPathuis 0:de08120b71bd 93 // First, now Write pointer to register 0x00----------------------------
GerritPathuis 0:de08120b71bd 94 adrss= (i2c_slave_addr1 << 1); // AS5510 Slave address lsb= 0 for write
GerritPathuis 0:de08120b71bd 95 oresult= i2c.write(adrss, 0x00, 1, 0); // write one byte
GerritPathuis 0:de08120b71bd 96 if (oresult != 0) pc.printf("No ACK bit! (33)\n\r");
GerritPathuis 0:de08120b71bd 97
GerritPathuis 0:de08120b71bd 98 // Second, now Read register 0x00 and 0x01--------------------------------
GerritPathuis 0:de08120b71bd 99 memset(off_data, 0, sizeof(off_data));
GerritPathuis 0:de08120b71bd 100 adrss= (i2c_slave_addr1 << 1) | 0x01; // AS5510 address lsb= 1 for read
GerritPathuis 0:de08120b71bd 101 oresult= i2c.read(adrss, off_data, 2, 0); // read two bytes
GerritPathuis 0:de08120b71bd 102
GerritPathuis 0:de08120b71bd 103 // Now analyse register 0x01 ----------------------------------------------
GerritPathuis 0:de08120b71bd 104 ocf_done= off_data[1] & 0x08; // mask off bits, 1= done
GerritPathuis 0:de08120b71bd 105 if (ocf_done== 0) return(0);
GerritPathuis 0:de08120b71bd 106 else return(1);
GerritPathuis 0:de08120b71bd 107 }
GerritPathuis 0:de08120b71bd 108
GerritPathuis 0:de08120b71bd 109
GerritPathuis 0:de08120b71bd 110 void read_field()
GerritPathuis 0:de08120b71bd 111 {
GerritPathuis 0:de08120b71bd 112 int adr=0;
GerritPathuis 0:de08120b71bd 113 char rx_data[2];
GerritPathuis 0:de08120b71bd 114 int rresult=0;
GerritPathuis 0:de08120b71bd 115 char lsb, msb;
GerritPathuis 0:de08120b71bd 116 unsigned int value;
GerritPathuis 0:de08120b71bd 117
GerritPathuis 0:de08120b71bd 118 // First, now Write pointer to register 0x00----------------------------
GerritPathuis 0:de08120b71bd 119 adr= (i2c_slave_addr1 << 1); // AS5510 address lsb= 0 for write
GerritPathuis 0:de08120b71bd 120 rresult= i2c.write(adr, 0x00, 1, 0); // write one byte to register 0x00 for magnetic field strength
GerritPathuis 0:de08120b71bd 121 if (rresult != 0) pc.printf("No ACK bit! (22)\n\r");
GerritPathuis 0:de08120b71bd 122
GerritPathuis 0:de08120b71bd 123 // Second, now Read register 0x00 and 0x01--------------------------------
GerritPathuis 0:de08120b71bd 124 memset(rx_data, 0, sizeof(rx_data));
GerritPathuis 0:de08120b71bd 125 adr= (i2c_slave_addr1 << 1) | 0x01; // AS5510 address lsb= 1 for read
GerritPathuis 0:de08120b71bd 126 rresult= i2c.read(adr, rx_data, 2, 0); // read two bytes
GerritPathuis 0:de08120b71bd 127
GerritPathuis 0:de08120b71bd 128
GerritPathuis 0:de08120b71bd 129 // Now analyse register 0x01 ----------------------------------------------
GerritPathuis 0:de08120b71bd 130 lsb= rx_data[0]; // get LSB
GerritPathuis 0:de08120b71bd 131 msb= rx_data[1]&0x03; // need only 2 low bits og MSB
GerritPathuis 0:de08120b71bd 132 value = ((msb & 0x03)<<8) + lsb;
GerritPathuis 0:de08120b71bd 133 pc.printf("Magnetic Field => msb= 0x%02X, lsb= 0x%02X, decimal 10-bit value = %u \r\n ", rx_data[0],rx_data[1], value);
GerritPathuis 0:de08120b71bd 134 }
GerritPathuis 0:de08120b71bd 135
GerritPathuis 0:de08120b71bd 136