HACK KUET
Driving Gyro MLX90609 using the SPI of mbed
main.cpp@0:d847fd15f903, 2012-05-12 (annotated)
- Committer:
- hack08
- Date:
- Sat May 12 14:27:40 2012 +0000
- Revision:
- 0:d847fd15f903
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| hack08 | 0:d847fd15f903 | 1 | /* |
| hack08 | 0:d847fd15f903 | 2 | Gyroscope Interfacing |
| hack08 | 0:d847fd15f903 | 3 | After recieving 16bit from Gyro if 15th bit is zero, the instruction is accepted |
| hack08 | 0:d847fd15f903 | 4 | */ |
| hack08 | 0:d847fd15f903 | 5 | |
| hack08 | 0:d847fd15f903 | 6 | #include "mbed.h" |
| hack08 | 0:d847fd15f903 | 7 | SPI spi(p5, p6, p7); // mosi, miso, sclk |
| hack08 | 0:d847fd15f903 | 8 | DigitalOut csGyro(p8); |
| hack08 | 0:d847fd15f903 | 9 | Serial pc(USBTX, USBRX); // tx, rx |
| hack08 | 0:d847fd15f903 | 10 | |
| hack08 | 0:d847fd15f903 | 11 | void activateADC() |
| hack08 | 0:d847fd15f903 | 12 | { |
| hack08 | 0:d847fd15f903 | 13 | unsigned int data1, data2; |
| hack08 | 0:d847fd15f903 | 14 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 15 | spi.write(0x93); // 0b10010100 |
| hack08 | 0:d847fd15f903 | 16 | /*Check if instruction recieved i.e */ |
| hack08 | 0:d847fd15f903 | 17 | //Send 2 dymmy byte of any combination |
| hack08 | 0:d847fd15f903 | 18 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 19 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 20 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 21 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 22 | |
| hack08 | 0:d847fd15f903 | 23 | if(data1 & 0x80) /*0b10000000*/ |
| hack08 | 0:d847fd15f903 | 24 | { |
| hack08 | 0:d847fd15f903 | 25 | pc.printf("\nInstruction not recieved %d %d", &data1, &data2); |
| hack08 | 0:d847fd15f903 | 26 | } |
| hack08 | 0:d847fd15f903 | 27 | else |
| hack08 | 0:d847fd15f903 | 28 | pc.printf("\n ADC activated "); |
| hack08 | 0:d847fd15f903 | 29 | } |
| hack08 | 0:d847fd15f903 | 30 | |
| hack08 | 0:d847fd15f903 | 31 | void sleepADC() |
| hack08 | 0:d847fd15f903 | 32 | { |
| hack08 | 0:d847fd15f903 | 33 | unsigned int data1, data2; |
| hack08 | 0:d847fd15f903 | 34 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 35 | spi.write(0x90); // 0b10010000 |
| hack08 | 0:d847fd15f903 | 36 | /*Check if instruction recieved i.e */ |
| hack08 | 0:d847fd15f903 | 37 | //Send 2 dymmy byte of any combination |
| hack08 | 0:d847fd15f903 | 38 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 39 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 40 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 41 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 42 | |
| hack08 | 0:d847fd15f903 | 43 | if(data1 & 0x80) /*0b10000000*/ |
| hack08 | 0:d847fd15f903 | 44 | { |
| hack08 | 0:d847fd15f903 | 45 | pc.printf("\nInstruction not recieved %d %d", &data1, &data2); |
| hack08 | 0:d847fd15f903 | 46 | } |
| hack08 | 0:d847fd15f903 | 47 | else |
| hack08 | 0:d847fd15f903 | 48 | pc.printf("\n ADC in sleep "); |
| hack08 | 0:d847fd15f903 | 49 | } |
| hack08 | 0:d847fd15f903 | 50 | |
| hack08 | 0:d847fd15f903 | 51 | unsigned int getAngularRate() |
| hack08 | 0:d847fd15f903 | 52 | { |
| hack08 | 0:d847fd15f903 | 53 | unsigned int result=0, data1, data2; |
| hack08 | 0:d847fd15f903 | 54 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 55 | spi.write(0x94); /* 0b10010100 Send SPI ADCC for Angular Rate (CHAN bit = 0)*/ |
| hack08 | 0:d847fd15f903 | 56 | /*Check if instruction recieved*/ |
| hack08 | 0:d847fd15f903 | 57 | //Send 2 dymmy byte of any combination |
| hack08 | 0:d847fd15f903 | 58 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 59 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 60 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 61 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 62 | |
| hack08 | 0:d847fd15f903 | 63 | if(data1 & 0x80 ) /*0b10000000*/ |
| hack08 | 0:d847fd15f903 | 64 | { |
| hack08 | 0:d847fd15f903 | 65 | pc.printf("\nInstruction not recieved"); |
| hack08 | 0:d847fd15f903 | 66 | } |
| hack08 | 0:d847fd15f903 | 67 | |
| hack08 | 0:d847fd15f903 | 68 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 69 | spi.write(0x80); /* 0b10000000 Send SPI ADCR Instruction*/ |
| hack08 | 0:d847fd15f903 | 70 | /*Send 2 dymmy byte*/ |
| hack08 | 0:d847fd15f903 | 71 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 72 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 73 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 74 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 75 | |
| hack08 | 0:d847fd15f903 | 76 | /*Check if instruction recieved*/ |
| hack08 | 0:d847fd15f903 | 77 | if(!(data1 & 0x80)) |
| hack08 | 0:d847fd15f903 | 78 | { |
| hack08 | 0:d847fd15f903 | 79 | while(!(data1 & 0x20)); // Wait while EOC is 0 |
| hack08 | 0:d847fd15f903 | 80 | result = ((data1 & 0x0F) << 7) + (data2>>1); |
| hack08 | 0:d847fd15f903 | 81 | } |
| hack08 | 0:d847fd15f903 | 82 | return result; |
| hack08 | 0:d847fd15f903 | 83 | |
| hack08 | 0:d847fd15f903 | 84 | } |
| hack08 | 0:d847fd15f903 | 85 | |
| hack08 | 0:d847fd15f903 | 86 | unsigned int getTemperature() |
| hack08 | 0:d847fd15f903 | 87 | { |
| hack08 | 0:d847fd15f903 | 88 | unsigned int result=0, data1, data2; |
| hack08 | 0:d847fd15f903 | 89 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 90 | spi.write(0x9C); /* 0b10011100 Send SPI ADCC for Temperature (CHAN bit = 1)*/ |
| hack08 | 0:d847fd15f903 | 91 | /*Check if instruction recieved*/ |
| hack08 | 0:d847fd15f903 | 92 | //Send 2 dymmy byte of any combination |
| hack08 | 0:d847fd15f903 | 93 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 94 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 95 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 96 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 97 | |
| hack08 | 0:d847fd15f903 | 98 | if(data1 & 0x80 ) /*0b10000000*/ |
| hack08 | 0:d847fd15f903 | 99 | { |
| hack08 | 0:d847fd15f903 | 100 | pc.printf("\nInstruction not recieved"); |
| hack08 | 0:d847fd15f903 | 101 | } |
| hack08 | 0:d847fd15f903 | 102 | |
| hack08 | 0:d847fd15f903 | 103 | csGyro=0; |
| hack08 | 0:d847fd15f903 | 104 | spi.write(0x80); /* 0b10000000 Send SPI ADCR Instruction*/ |
| hack08 | 0:d847fd15f903 | 105 | /*Send 2 dymmy byte*/ |
| hack08 | 0:d847fd15f903 | 106 | data1 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 107 | data2 = spi.write(0x00); |
| hack08 | 0:d847fd15f903 | 108 | wait_us(200); |
| hack08 | 0:d847fd15f903 | 109 | csGyro=1; |
| hack08 | 0:d847fd15f903 | 110 | |
| hack08 | 0:d847fd15f903 | 111 | /*Check if instruction accepted*/ |
| hack08 | 0:d847fd15f903 | 112 | if(!(data1 & 0x80)) |
| hack08 | 0:d847fd15f903 | 113 | { |
| hack08 | 0:d847fd15f903 | 114 | while(!(data1 & 0x20)); // Wait while EOC is 0 |
| hack08 | 0:d847fd15f903 | 115 | result = ((data1 & 0x0F) << 7) + (data2>>1); |
| hack08 | 0:d847fd15f903 | 116 | } |
| hack08 | 0:d847fd15f903 | 117 | return result; |
| hack08 | 0:d847fd15f903 | 118 | } |
| hack08 | 0:d847fd15f903 | 119 | |
| hack08 | 0:d847fd15f903 | 120 | int adcToAngularRate(unsigned int result) |
| hack08 | 0:d847fd15f903 | 121 | { |
| hack08 | 0:d847fd15f903 | 122 | int conversion = (result * 25/12)+400; |
| hack08 | 0:d847fd15f903 | 123 | signed int offset = 2500; |
| hack08 | 0:d847fd15f903 | 124 | return (conversion - offset)/6.67; /*from the data sheet, R2 version is 6.67 E2 is 13.33 and N2 is 26.67 mV/deg change accordingly.*/ |
| hack08 | 0:d847fd15f903 | 125 | } |
| hack08 | 0:d847fd15f903 | 126 | |
| hack08 | 0:d847fd15f903 | 127 | int adcToTemperature(unsigned int result) |
| hack08 | 0:d847fd15f903 | 128 | { |
| hack08 | 0:d847fd15f903 | 129 | |
| hack08 | 0:d847fd15f903 | 130 | int conversion = (result * 25/16)+300; |
| hack08 | 0:d847fd15f903 | 131 | signed int offset = 2500; |
| hack08 | 0:d847fd15f903 | 132 | return 25 + ((conversion - offset)/10); /* from the data sheet factor is 10mV/K */ |
| hack08 | 0:d847fd15f903 | 133 | } |
| hack08 | 0:d847fd15f903 | 134 | |
| hack08 | 0:d847fd15f903 | 135 | int main() |
| hack08 | 0:d847fd15f903 | 136 | { |
| hack08 | 0:d847fd15f903 | 137 | unsigned int angle, temper; |
| hack08 | 0:d847fd15f903 | 138 | spi.format(8,3); |
| hack08 | 0:d847fd15f903 | 139 | spi.frequency(1000000); |
| hack08 | 0:d847fd15f903 | 140 | while(1){ |
| hack08 | 0:d847fd15f903 | 141 | activateADC(); |
| hack08 | 0:d847fd15f903 | 142 | |
| hack08 | 0:d847fd15f903 | 143 | angle=getAngularRate(); |
| hack08 | 0:d847fd15f903 | 144 | temper=getTemperature(); |
| hack08 | 0:d847fd15f903 | 145 | pc.printf("\nAngular Rate %d",adcToAngularRate(angle)); |
| hack08 | 0:d847fd15f903 | 146 | pc.printf("\nTemperature %d",adcToTemperature(temper)); |
| hack08 | 0:d847fd15f903 | 147 | sleepADC(); |
| hack08 | 0:d847fd15f903 | 148 | wait(1); |
| hack08 | 0:d847fd15f903 | 149 | } |
| hack08 | 0:d847fd15f903 | 150 | } |