Rev Author Line No. Line
2767 kaklik 1 #include <main.h>
2  
3 /*
4 MPL115A1 SDN - +3.3V (always power on)
5 MPL115A1 #CS - PIN_C2
2769 kaklik 6 MPL115A1 DOUT - PIN_C4
7 MPL115A1 DIN - PIN_C5
2767 kaklik 8 MPL115A1 SCLK - PIN_C3
9 MPL115A1 GND - GND
10 MPL115A1 VDD - +3.3V
11 */
12  
13 #define CSN_SPI PIN_C2
14  
15 // SPI mode definitions.
16 #define SPI_MODE_0 (SPI_L_TO_H | SPI_XMIT_L_TO_H)
17 #define SPI_MODE_1 (SPI_L_TO_H)
18 #define SPI_MODE_2 (SPI_H_TO_L)
19 #define SPI_MODE_3 (SPI_H_TO_L | SPI_XMIT_L_TO_H)
20  
2777 kaklik 21 float a0; // correctiaon coefficients
2775 kaklik 22 float b1;
23 float b2;
24 float c12;
2767 kaklik 25  
26  
2775 kaklik 27 void MPL_init()
2772 kaklik 28 {
29 unsigned int8 a0_MSB, a0_LSB;
30 unsigned int8 b1_MSB, b1_LSB;
31 unsigned int8 b2_MSB, b2_LSB;
32 unsigned int8 c12_MSB, c12_LSB;
2767 kaklik 33  
2772 kaklik 34 output_low(CSN_SPI);
2767 kaklik 35  
2772 kaklik 36 spi_write(0x88); // get MSB for a0
37 a0_MSB = spi_read(0x00);
38 spi_write(0x8A); // get LSB for a0
39 a0_LSB = spi_read(0x00);
2767 kaklik 40  
2777 kaklik 41 spi_write(0x8C); // get MSB for b1
2772 kaklik 42 b1_MSB = spi_read(0x00);
2777 kaklik 43 spi_write(0x8E); // get LSB for b1
2772 kaklik 44 b1_LSB = spi_read(0x00);
2767 kaklik 45  
2777 kaklik 46 spi_write(0x90); // get MSB for b2
2772 kaklik 47 b2_MSB = spi_read(0x00);
2777 kaklik 48 spi_write(0x92); // get LSB for b2
2772 kaklik 49 b2_LSB = spi_read(0x00);
50  
2777 kaklik 51 spi_write(0x94); // get MSB for c12
2772 kaklik 52 c12_MSB = spi_read(0x00);
2777 kaklik 53 spi_write(0x96); // get LSB for c12
2772 kaklik 54 c12_LSB = spi_read(0x00);
55  
56 spi_read(0x00);
57 output_high(CSN_SPI);
2777 kaklik 58  
59 // translate to floating point number
2767 kaklik 60  
2776 kaklik 61 a0 = ((unsigned int16) a0_MSB << 5) + (a0_LSB >> 3) + (a0_LSB & 0x07)/8.0;
2775 kaklik 62 b1 = ((((b1_MSB & 0x1F) * 0x100) + b1_LSB) / 8192.0) - 3;
2776 kaklik 63 b2 = ((((unsigned int16) (b2_MSB - 0x80) << 8) + b2_LSB)/ 16384.0) - 2;
2775 kaklik 64 c12 =(((c12_MSB * 0x100) + c12_LSB)/16777216.0);
2772 kaklik 65 }
66  
67 float MPL_get_pressure()
68 {
2774 kaklik 69 unsigned int8 LSB_data, MSB_data;
70 unsigned int16 ADC_pressure, ADC_temperature;
2775 kaklik 71 float Pcomp;
2772 kaklik 72  
73 output_low(CSN_SPI); //Start temperature and pressure conversion
74 spi_write(0x24);
75 spi_write(0x00);
2767 kaklik 76 output_high(CSN_SPI);
77  
2774 kaklik 78 delay_ms(10);
2772 kaklik 79  
80 output_low(CSN_SPI); // get MSB for Pressure
81 spi_write(0x80);
2775 kaklik 82 MSB_data = spi_read(0x00);
83 spi_write(0x82); // get LSB for Pressure
2772 kaklik 84 LSB_data = spi_read(0x00);
2774 kaklik 85 output_high(CSN_SPI);
2767 kaklik 86  
2775 kaklik 87 ADC_pressure = (((unsigned int16) MSB_data << 8) + LSB_data ) >> 6; // conversion of 8bit registers to 16bit variable
2767 kaklik 88  
2774 kaklik 89 output_low(CSN_SPI);
2772 kaklik 90 spi_write(0x84);
2775 kaklik 91 MSB_data = spi_read(0x00);
92 spi_write(0x86); // get LSB for Temperature
2772 kaklik 93 LSB_data = spi_read(0x00);
94 spi_read(0x00);
95 output_high(CSN_SPI);
96  
2775 kaklik 97 ADC_temperature = (((unsigned int16) MSB_data << 8) + LSB_data ) >> 6; // conversion of 8bit registers to 16bit variable
98  
2777 kaklik 99 Pcomp = (a0 + (b1 + c12 * ADC_temperature) * ADC_pressure + b2 * ADC_temperature ); // compute relative compensated pressure
2772 kaklik 100  
2777 kaklik 101 return (Pcomp * ((115.0 - 50.0)/1023.0) + 50.0); // return absolute pressure
102 }
2776 kaklik 103  
2777 kaklik 104 float MPL_get_temperature()
105 {
106 unsigned int8 LSB_data, MSB_data;
107 unsigned int16 ADC_temperature;
108  
109 output_low(CSN_SPI); //Start temperature and pressure conversion
110 spi_write(0x22);
111 spi_write(0x00);
112 output_high(CSN_SPI);
113  
114 delay_ms(10);
115  
116 output_low(CSN_SPI);
117 spi_write(0x84);
118 MSB_data = spi_read(0x00);
119 spi_write(0x86); // get LSB for Temperature
120 LSB_data = spi_read(0x00);
121 spi_read(0x00);
122 output_high(CSN_SPI);
123  
124 ADC_temperature = (((unsigned int16) MSB_data << 8) + LSB_data ) >> 6; // conversion of 8bit registers to 16bit variable
125  
126 return ( ((float) ADC_temperature - 498.0)/-5.35) + 25.0; // return temperature in deg C
2767 kaklik 127 }
2772 kaklik 128  
129 void main()
130 {
131 printf("Start \r\n");
132 setup_spi(SPI_MASTER | SPI_MODE_0 | SPI_CLK_DIV_64);
133 output_high(CSN_SPI);
134 delay_ms(100);
135  
2777 kaklik 136 MPL_init(); // get correction coeffivcients from the sensor
2772 kaklik 137  
138 while(true)
139 {
2777 kaklik 140 printf("%f %f \r\n", MPL_get_pressure(), MPL_get_temperature());
2774 kaklik 141 delay_ms(500);
2772 kaklik 142 }
143 }