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.
main.cpp@7:c90a88ae043b, 2017-11-13 (annotated)
- Committer:
- GerritPathuis
- Date:
- Mon Nov 13 21:02:12 2017 +0000
- Revision:
- 7:c90a88ae043b
- Parent:
- 5:cec4c7caf8b7
mbed revision 157
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
GerritPathuis | 0:de08120b71bd | 1 | #include "mbed.h" |
GerritPathuis | 0:de08120b71bd | 2 | ////////////////////////////////////////////////// |
GerritPathuis | 0:de08120b71bd | 3 | // Testing AS5510 sensor with K22F // |
GerritPathuis | 2:dc991201ff3c | 4 | // test results are sent to Tera Term // |
GerritPathuis | 2:dc991201ff3c | 5 | // I2C frequency set @ 400kHz // |
GerritPathuis | 0:de08120b71bd | 6 | // // |
GerritPathuis | 2:dc991201ff3c | 7 | // Note 1) // |
GerritPathuis | 2:dc991201ff3c | 8 | // I2C address 0x1C is used by FXOS8700CQ // |
GerritPathuis | 0:de08120b71bd | 9 | // 3-axis accelerometer and 3-axis magetometer // |
GerritPathuis | 2:dc991201ff3c | 10 | // // |
GerritPathuis | 2:dc991201ff3c | 11 | // Note 2) // |
GerritPathuis | 2:dc991201ff3c | 12 | // Without magnet present the AS5510 sensor is // |
GerritPathuis | 2:dc991201ff3c | 13 | // expected to output a value of approx 511 // |
GerritPathuis | 2:dc991201ff3c | 14 | // (1023/2= 511 // |
GerritPathuis | 3:c57454632e8d | 15 | // // |
GerritPathuis | 3:c57454632e8d | 16 | // Note 3) // |
GerritPathuis | 3:c57454632e8d | 17 | // Lateral Movement of a simple 2-pole magnet. // |
GerritPathuis | 3:c57454632e8d | 18 | // Magnet size diameter 1mm length 2mm // |
GerritPathuis | 3:c57454632e8d | 19 | // Distance to sensor approx 0.8mm // |
GerritPathuis | 3:c57454632e8d | 20 | // Output 10bit resolution // |
GerritPathuis | 0:de08120b71bd | 21 | ////////////////////////////////////////////////// |
GerritPathuis | 2:dc991201ff3c | 22 | Serial pc(USBTX, USBRX); // tx, rx |
GerritPathuis | 2:dc991201ff3c | 23 | I2C i2c(PTB3, PTB2); // SDA, SCL (for K22F) |
GerritPathuis | 0:de08120b71bd | 24 | |
GerritPathuis | 5:cec4c7caf8b7 | 25 | const int i2c_slave_addr1 = 0x56; // sensor AS5510 number 1 (7 bits), 0x56 or 0x57 |
GerritPathuis | 5:cec4c7caf8b7 | 26 | const int i2c_slave_addr2 = 0x57; // sensor AS5510 number 2 (7 bits), 0x56 or 0x57 |
GerritPathuis | 0:de08120b71bd | 27 | |
GerritPathuis | 0:de08120b71bd | 28 | //--- public functions--- |
GerritPathuis | 4:536bd8cce754 | 29 | void init_as5510(int); |
GerritPathuis | 4:536bd8cce754 | 30 | void read_field(int); |
GerritPathuis | 4:536bd8cce754 | 31 | int offset_comp(int); |
GerritPathuis | 0:de08120b71bd | 32 | void look_for_hardware_i2c(void); |
GerritPathuis | 0:de08120b71bd | 33 | |
GerritPathuis | 0:de08120b71bd | 34 | |
GerritPathuis | 0:de08120b71bd | 35 | int main() |
GerritPathuis | 0:de08120b71bd | 36 | { |
GerritPathuis | 4:536bd8cce754 | 37 | i2c.frequency(400 * 1000); // 0.4 mHz |
GerritPathuis | 2:dc991201ff3c | 38 | wait_ms(2); // Power Up wait |
GerritPathuis | 0:de08120b71bd | 39 | |
GerritPathuis | 2:dc991201ff3c | 40 | look_for_hardware_i2c(); // Hardware present ? |
GerritPathuis | 5:cec4c7caf8b7 | 41 | init_as5510(i2c_slave_addr1); // Initialize |
GerritPathuis | 5:cec4c7caf8b7 | 42 | init_as5510(i2c_slave_addr2); // Initialize |
GerritPathuis | 0:de08120b71bd | 43 | |
GerritPathuis | 0:de08120b71bd | 44 | //----------Setup register---------------------- |
GerritPathuis | 5:cec4c7caf8b7 | 45 | while (!offset_comp(i2c_slave_addr1)); |
GerritPathuis | 5:cec4c7caf8b7 | 46 | while (!offset_comp(i2c_slave_addr2)); |
GerritPathuis | 2:dc991201ff3c | 47 | pc.printf("Offset compensation process is completed \r\n"); |
GerritPathuis | 2:dc991201ff3c | 48 | |
GerritPathuis | 2:dc991201ff3c | 49 | //----------Get the results---------------------- |
GerritPathuis | 4:536bd8cce754 | 50 | while (true) { |
GerritPathuis | 5:cec4c7caf8b7 | 51 | read_field(i2c_slave_addr1); // Read magnetic Field sensor #1 |
GerritPathuis | 5:cec4c7caf8b7 | 52 | read_field(i2c_slave_addr2); // Read magnetic Field sensor #2 |
GerritPathuis | 4:536bd8cce754 | 53 | } |
GerritPathuis | 0:de08120b71bd | 54 | } |
GerritPathuis | 0:de08120b71bd | 55 | |
GerritPathuis | 0:de08120b71bd | 56 | |
GerritPathuis | 0:de08120b71bd | 57 | void look_for_hardware_i2c() |
GerritPathuis | 0:de08120b71bd | 58 | { |
GerritPathuis | 0:de08120b71bd | 59 | pc.printf("\r\n\n\n"); |
GerritPathuis | 0:de08120b71bd | 60 | pc.printf("Note I2C address 0x1C used by FXOS8700CQ 3-axis accelerometer and 3-axis magetometer\r\n"); |
GerritPathuis | 0:de08120b71bd | 61 | pc.printf("Start hardware search..... \r\n"); |
GerritPathuis | 0:de08120b71bd | 62 | |
GerritPathuis | 0:de08120b71bd | 63 | int count = 0; |
GerritPathuis | 0:de08120b71bd | 64 | for (int address=12; address<256; address+=2) { |
GerritPathuis | 2:dc991201ff3c | 65 | if (!i2c.write(address, NULL, 0)) { // 0 returned is OK |
GerritPathuis | 0:de08120b71bd | 66 | pc.printf(" - I2C device found at address 0x%02X\n\r", address >>1); |
GerritPathuis | 0:de08120b71bd | 67 | count++; |
GerritPathuis | 0:de08120b71bd | 68 | } |
GerritPathuis | 0:de08120b71bd | 69 | } |
GerritPathuis | 0:de08120b71bd | 70 | pc.printf("%d devices found \n\r", count); |
GerritPathuis | 0:de08120b71bd | 71 | } |
GerritPathuis | 0:de08120b71bd | 72 | |
GerritPathuis | 4:536bd8cce754 | 73 | void init_as5510(int i2c_address) |
GerritPathuis | 0:de08120b71bd | 74 | { |
GerritPathuis | 0:de08120b71bd | 75 | int i2c_adrs=0; |
GerritPathuis | 0:de08120b71bd | 76 | char idata[2]; |
GerritPathuis | 0:de08120b71bd | 77 | int result=0; |
GerritPathuis | 0:de08120b71bd | 78 | |
GerritPathuis | 0:de08120b71bd | 79 | pc.printf("\r\n"); |
GerritPathuis | 0:de08120b71bd | 80 | pc.printf("Start AS5510 init.. \r\n"); |
GerritPathuis | 0:de08120b71bd | 81 | |
GerritPathuis | 4:536bd8cce754 | 82 | i2c_adrs= (i2c_address << 1); // AS5510 Slave address lsb= 0 for write |
GerritPathuis | 4:536bd8cce754 | 83 | |
GerritPathuis | 2:dc991201ff3c | 84 | //---------- Magnet selection -------------------------------- |
GerritPathuis | 4:536bd8cce754 | 85 | //----0x00= <50mT-----------Strong magnet |
GerritPathuis | 2:dc991201ff3c | 86 | //----0x01= <25mT |
GerritPathuis | 2:dc991201ff3c | 87 | //----0x02= <18.7mT |
GerritPathuis | 4:536bd8cce754 | 88 | //----0x03= <12.5mT---------Weak magnet |
GerritPathuis | 2:dc991201ff3c | 89 | //----------------------------------------------------------- |
GerritPathuis | 0:de08120b71bd | 90 | idata[0]=0x0B; // Register for Sensitivity |
GerritPathuis | 2:dc991201ff3c | 91 | idata[1]=0x00; // Byte |
GerritPathuis | 0:de08120b71bd | 92 | result= i2c.write(i2c_adrs, idata, 2, 0); // Now write_sensitivity |
GerritPathuis | 0:de08120b71bd | 93 | if (result != 0) pc.printf("No ACK bit! (09)\n\r"); |
GerritPathuis | 0:de08120b71bd | 94 | |
GerritPathuis | 2:dc991201ff3c | 95 | //----------- Operation mode selection------------------------ |
GerritPathuis | 0:de08120b71bd | 96 | idata[0]=0x02; // 0x02 address setup register for operation, speed, polarity |
GerritPathuis | 0:de08120b71bd | 97 | idata[1]=0x04; // Normal Operation, Slow mode (1), NORMAL Polarity (0), Power Up (0) |
GerritPathuis | 0:de08120b71bd | 98 | result= i2c.write(i2c_adrs, idata, 2, 0); // Now write_operation |
GerritPathuis | 0:de08120b71bd | 99 | if (result != 0) pc.printf("No ACK bit! (11)\n\r"); |
GerritPathuis | 0:de08120b71bd | 100 | |
GerritPathuis | 0:de08120b71bd | 101 | pc.printf("AS5510 init done\r\n"); |
GerritPathuis | 0:de08120b71bd | 102 | } |
GerritPathuis | 0:de08120b71bd | 103 | |
GerritPathuis | 0:de08120b71bd | 104 | |
GerritPathuis | 4:536bd8cce754 | 105 | int offset_comp(int i2c_address) |
GerritPathuis | 0:de08120b71bd | 106 | { |
GerritPathuis | 0:de08120b71bd | 107 | int adrss=0; |
GerritPathuis | 0:de08120b71bd | 108 | int oresult=0; |
GerritPathuis | 0:de08120b71bd | 109 | char off_data[2]; |
GerritPathuis | 0:de08120b71bd | 110 | int ocf_done=0; |
GerritPathuis | 0:de08120b71bd | 111 | |
GerritPathuis | 0:de08120b71bd | 112 | // First, now Write pointer to register 0x00---------------------------- |
GerritPathuis | 4:536bd8cce754 | 113 | adrss= (i2c_address << 1); // AS5510 Slave address lsb= 0 for write |
GerritPathuis | 0:de08120b71bd | 114 | oresult= i2c.write(adrss, 0x00, 1, 0); // write one byte |
GerritPathuis | 0:de08120b71bd | 115 | if (oresult != 0) pc.printf("No ACK bit! (33)\n\r"); |
GerritPathuis | 0:de08120b71bd | 116 | |
GerritPathuis | 0:de08120b71bd | 117 | // Second, now Read register 0x00 and 0x01-------------------------------- |
GerritPathuis | 0:de08120b71bd | 118 | memset(off_data, 0, sizeof(off_data)); |
GerritPathuis | 4:536bd8cce754 | 119 | adrss= (i2c_address << 1) | 0x01; // AS5510 address lsb= 1 for read |
GerritPathuis | 0:de08120b71bd | 120 | oresult= i2c.read(adrss, off_data, 2, 0); // read two bytes |
GerritPathuis | 0:de08120b71bd | 121 | |
GerritPathuis | 0:de08120b71bd | 122 | // Now analyse register 0x01 ---------------------------------------------- |
GerritPathuis | 0:de08120b71bd | 123 | ocf_done= off_data[1] & 0x08; // mask off bits, 1= done |
GerritPathuis | 2:dc991201ff3c | 124 | if (ocf_done== 0) return(0); // return(0)= compensation process is pending |
GerritPathuis | 2:dc991201ff3c | 125 | else return(1); // return(1)= compensation process is completed |
GerritPathuis | 0:de08120b71bd | 126 | } |
GerritPathuis | 0:de08120b71bd | 127 | |
GerritPathuis | 0:de08120b71bd | 128 | |
GerritPathuis | 4:536bd8cce754 | 129 | void read_field(int i2c_address) |
GerritPathuis | 0:de08120b71bd | 130 | { |
GerritPathuis | 0:de08120b71bd | 131 | int adr=0; |
GerritPathuis | 0:de08120b71bd | 132 | char rx_data[2]; |
GerritPathuis | 0:de08120b71bd | 133 | int rresult=0; |
GerritPathuis | 0:de08120b71bd | 134 | char lsb, msb; |
GerritPathuis | 0:de08120b71bd | 135 | unsigned int value; |
GerritPathuis | 0:de08120b71bd | 136 | |
GerritPathuis | 0:de08120b71bd | 137 | // First, now Write pointer to register 0x00---------------------------- |
GerritPathuis | 4:536bd8cce754 | 138 | adr= (i2c_address << 1); // AS5510 address lsb= 0 for write |
GerritPathuis | 0:de08120b71bd | 139 | rresult= i2c.write(adr, 0x00, 1, 0); // write one byte to register 0x00 for magnetic field strength |
GerritPathuis | 0:de08120b71bd | 140 | if (rresult != 0) pc.printf("No ACK bit! (22)\n\r"); |
GerritPathuis | 0:de08120b71bd | 141 | |
GerritPathuis | 0:de08120b71bd | 142 | // Second, now Read register 0x00 and 0x01-------------------------------- |
GerritPathuis | 0:de08120b71bd | 143 | memset(rx_data, 0, sizeof(rx_data)); |
GerritPathuis | 4:536bd8cce754 | 144 | adr= (i2c_address << 1) | 0x01; // AS5510 address lsb= 1 for read |
GerritPathuis | 0:de08120b71bd | 145 | rresult= i2c.read(adr, rx_data, 2, 0); // read two bytes |
GerritPathuis | 0:de08120b71bd | 146 | |
GerritPathuis | 0:de08120b71bd | 147 | |
GerritPathuis | 0:de08120b71bd | 148 | // Now analyse register 0x01 ---------------------------------------------- |
GerritPathuis | 0:de08120b71bd | 149 | lsb= rx_data[0]; // get LSB |
GerritPathuis | 0:de08120b71bd | 150 | msb= rx_data[1]&0x03; // need only 2 low bits og MSB |
GerritPathuis | 0:de08120b71bd | 151 | value = ((msb & 0x03)<<8) + lsb; |
GerritPathuis | 4:536bd8cce754 | 152 | pc.printf("I2C adres= 0x%02X, Magnetic Field => msb= 0x%02X, lsb= 0x%02X, decimal 10-bit value = %u \r\n ", i2c_address, rx_data[0],rx_data[1], value); |
GerritPathuis | 0:de08120b71bd | 153 | } |
GerritPathuis | 0:de08120b71bd | 154 | |
GerritPathuis | 0:de08120b71bd | 155 |