PixArt / Mbed OS 3901_referenceFirmware

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Welcome to the code repository for PixArt's PMW3901MB sensor and evaluation board.

For general information about this product, please visit this product's components page here:
https://os.mbed.com/components/PMW3901MB-Far-Field-Optical-Motion-Track/

For guides and tips on how to setup and evaluate the PMW3901MB sensor with the Nordic nRF52-DK microcontroller using this reference code, please visit this guide:
https://os.mbed.com/teams/PixArt/code/3901_referenceFirmware/wiki/Guide-for-nRF52-DK-Platform

For guides and tips on how to setup and evaluate the PMW3901MB sensor with any microcontroller using this reference code, please visit this guide:
https://os.mbed.com/teams/PixArt/code/3901_referenceFirmware/wiki/Guide-for-Any-Platform

commHeaders/SPIcommFunctions.h@0:c00f2464eee3, 2018-03-14 (annotated)

Committer:
PixArtVY
Date:
Wed Mar 14 21:22:43 2018 +0000
Revision:
0:c00f2464eee3
First release.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
PixArtVY 0:c00f2464eee3 1 //=========================================================================
PixArtVY 0:c00f2464eee3 2 //Communication pinouts for serial COM port, SPI, and interrupts
PixArtVY 0:c00f2464eee3 3 //=========================================================================
PixArtVY 0:c00f2464eee3 4 static Serial pc(USBTX, USBRX); //PC comm
PixArtVY 0:c00f2464eee3 5 static SPI spi(p23, p24, p25); //mosi, miso, sclk
PixArtVY 0:c00f2464eee3 6 static DigitalOut cs(p22); //chip select
PixArtVY 0:c00f2464eee3 7
PixArtVY 0:c00f2464eee3 8
PixArtVY 0:c00f2464eee3 9 //=========================================================================
PixArtVY 0:c00f2464eee3 10 //Variables and arrays used for communications and data storage
PixArtVY 0:c00f2464eee3 11 //=========================================================================
PixArtVY 0:c00f2464eee3 12 int8_t deltaX_low, deltaY_low; //Stores the low-bits of movement data.
PixArtVY 0:c00f2464eee3 13 int16_t deltaX_high, deltaY_high; //Stores the high-bits of movement data.
PixArtVY 0:c00f2464eee3 14 int16_t deltaX, deltaY; //Stores the combined value of low and high bits.
PixArtVY 0:c00f2464eee3 15 int16_t totalX, totalY = 0; //Stores the total deltaX and deltaY moved during runtime.
PixArtVY 0:c00f2464eee3 16
PixArtVY 0:c00f2464eee3 17
PixArtVY 0:c00f2464eee3 18 //=========================================================================
PixArtVY 0:c00f2464eee3 19 //Functions used to communicate with the sensor and grab/print data
PixArtVY 0:c00f2464eee3 20 //=========================================================================
PixArtVY 0:c00f2464eee3 21 uint8_t readRegister(uint8_t addr);
PixArtVY 0:c00f2464eee3 22 //This function takes an 8-bit address in the form 0x00 and returns an 8-bit value in the form 0x00.
PixArtVY 0:c00f2464eee3 23
PixArtVY 0:c00f2464eee3 24 void writeRegister(uint8_t addr, uint8_t data);
PixArtVY 0:c00f2464eee3 25 //This function takes an 8-bit address and 8-bit data. Writes the given data to the given address.
PixArtVY 0:c00f2464eee3 26
PixArtVY 0:c00f2464eee3 27 void initializeSensor(void);
PixArtVY 0:c00f2464eee3 28 //Sets all of the registers needed for initialization and performance optimization.
PixArtVY 0:c00f2464eee3 29
PixArtVY 0:c00f2464eee3 30 void grabData(void);
PixArtVY 0:c00f2464eee3 31 //Grabs the deltaX and deltaY information from the proper registers and formats it into the proper format.
PixArtVY 0:c00f2464eee3 32
PixArtVY 0:c00f2464eee3 33 void printData(void);
PixArtVY 0:c00f2464eee3 34 //Prints the data out to a serial terminal.
PixArtVY 0:c00f2464eee3 35
PixArtVY 0:c00f2464eee3 36
PixArtVY 0:c00f2464eee3 37
PixArtVY 0:c00f2464eee3 38
PixArtVY 0:c00f2464eee3 39
PixArtVY 0:c00f2464eee3 40 //=========================================================================
PixArtVY 0:c00f2464eee3 41 //Functions definitions
PixArtVY 0:c00f2464eee3 42 //=========================================================================
PixArtVY 0:c00f2464eee3 43 uint8_t readRegister(uint8_t addr)
PixArtVY 0:c00f2464eee3 44 {
PixArtVY 0:c00f2464eee3 45 cs = 0; //Set chip select low/active
PixArtVY 0:c00f2464eee3 46 addr = addr & 0x7F; //Set MSB to 0 to indicate read operation
PixArtVY 0:c00f2464eee3 47 spi.write(addr); //Write the given address
PixArtVY 0:c00f2464eee3 48 wait_us(35); //Add a tiny delay after sending address for some internal cycle timing.
PixArtVY 0:c00f2464eee3 49 uint8_t data_read = spi.write(0x00); //Throw dummy byte after sending address to receieve data
PixArtVY 0:c00f2464eee3 50 cs = 1; //Set chip select back to high/inactive
PixArtVY 0:c00f2464eee3 51 return data_read; //Returns 8-bit data from register
PixArtVY 0:c00f2464eee3 52 }
PixArtVY 0:c00f2464eee3 53
PixArtVY 0:c00f2464eee3 54
PixArtVY 0:c00f2464eee3 55 //=========================================================================
PixArtVY 0:c00f2464eee3 56 void writeRegister(uint8_t addr, uint8_t data)
PixArtVY 0:c00f2464eee3 57 {
PixArtVY 0:c00f2464eee3 58 cs = 0; //Set chip select low/active
PixArtVY 0:c00f2464eee3 59 addr = addr | 0x80; //Set MSB to 1 to indicate write operation
PixArtVY 0:c00f2464eee3 60 spi.write(addr); //Write the given address
PixArtVY 0:c00f2464eee3 61 spi.write(data); //Write the given data
PixArtVY 0:c00f2464eee3 62 cs = 1; //Set chip select back to high/inactive
PixArtVY 0:c00f2464eee3 63
PixArtVY 0:c00f2464eee3 64 //pc.printf("R:%2X, D:%2X\n\r", addr, readRegister(addr));
PixArtVY 0:c00f2464eee3 65 //Uncomment this line for debugging. Prints every register write operation.
PixArtVY 0:c00f2464eee3 66 }
PixArtVY 0:c00f2464eee3 67
PixArtVY 0:c00f2464eee3 68
PixArtVY 0:c00f2464eee3 69 //=========================================================================
PixArtVY 0:c00f2464eee3 70 void initializeSensor(void)
PixArtVY 0:c00f2464eee3 71 {
PixArtVY 0:c00f2464eee3 72 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 73 writeRegister(0x55, 0x01);
PixArtVY 0:c00f2464eee3 74 writeRegister(0x50, 0x07);
PixArtVY 0:c00f2464eee3 75 writeRegister(0x7F, 0x0E);
PixArtVY 0:c00f2464eee3 76 writeRegister(0x43, 0x10);
PixArtVY 0:c00f2464eee3 77
PixArtVY 0:c00f2464eee3 78 if(readRegister(0x67) & 0x40)
PixArtVY 0:c00f2464eee3 79 writeRegister(0x48, 0x04);
PixArtVY 0:c00f2464eee3 80
PixArtVY 0:c00f2464eee3 81 else
PixArtVY 0:c00f2464eee3 82 writeRegister(0x48, 0x02);
PixArtVY 0:c00f2464eee3 83
PixArtVY 0:c00f2464eee3 84 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 85 writeRegister(0x51, 0x7B);
PixArtVY 0:c00f2464eee3 86 writeRegister(0x50, 0x00);
PixArtVY 0:c00f2464eee3 87 writeRegister(0x55, 0x00);
PixArtVY 0:c00f2464eee3 88 writeRegister(0x7F, 0x0E);
PixArtVY 0:c00f2464eee3 89
PixArtVY 0:c00f2464eee3 90 if(readRegister(0x73) == 0x00)
PixArtVY 0:c00f2464eee3 91 {
PixArtVY 0:c00f2464eee3 92 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 93 writeRegister(0x61, 0xAD);
PixArtVY 0:c00f2464eee3 94 writeRegister(0x51, 0x70);
PixArtVY 0:c00f2464eee3 95 writeRegister(0x7F, 0x0E);
PixArtVY 0:c00f2464eee3 96
PixArtVY 0:c00f2464eee3 97 if(readRegister(0x70) <= 28)
PixArtVY 0:c00f2464eee3 98 writeRegister(0x70, readRegister(0x70) + 14);
PixArtVY 0:c00f2464eee3 99
PixArtVY 0:c00f2464eee3 100 else
PixArtVY 0:c00f2464eee3 101 writeRegister(0x70, readRegister(0x70) + 11);
PixArtVY 0:c00f2464eee3 102
PixArtVY 0:c00f2464eee3 103 writeRegister(0x71, readRegister(0x71) * 45/100);
PixArtVY 0:c00f2464eee3 104 }
PixArtVY 0:c00f2464eee3 105
PixArtVY 0:c00f2464eee3 106 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 107 writeRegister(0x61, 0xAD);
PixArtVY 0:c00f2464eee3 108 writeRegister(0x7F, 0x03);
PixArtVY 0:c00f2464eee3 109 writeRegister(0x40, 0x00);
PixArtVY 0:c00f2464eee3 110 writeRegister(0x7F, 0x05);
PixArtVY 0:c00f2464eee3 111 writeRegister(0x41, 0xB3);
PixArtVY 0:c00f2464eee3 112 writeRegister(0x43, 0xF1);
PixArtVY 0:c00f2464eee3 113 writeRegister(0x45, 0x14);
PixArtVY 0:c00f2464eee3 114 writeRegister(0x5B, 0x32);
PixArtVY 0:c00f2464eee3 115 writeRegister(0x5F, 0x34);
PixArtVY 0:c00f2464eee3 116 writeRegister(0x7B, 0x08);
PixArtVY 0:c00f2464eee3 117 writeRegister(0x7F, 0x06);
PixArtVY 0:c00f2464eee3 118 writeRegister(0x44, 0x1B);
PixArtVY 0:c00f2464eee3 119 writeRegister(0x40, 0xBF);
PixArtVY 0:c00f2464eee3 120 writeRegister(0x4E, 0x3F);
PixArtVY 0:c00f2464eee3 121 writeRegister(0x7F, 0x06);
PixArtVY 0:c00f2464eee3 122 writeRegister(0x44, 0x1B);
PixArtVY 0:c00f2464eee3 123 writeRegister(0x40, 0xBF);
PixArtVY 0:c00f2464eee3 124 writeRegister(0x4E, 0x3F);
PixArtVY 0:c00f2464eee3 125 writeRegister(0x7F, 0x08);
PixArtVY 0:c00f2464eee3 126 writeRegister(0x65, 0x20);
PixArtVY 0:c00f2464eee3 127 writeRegister(0x6A, 0x18);
PixArtVY 0:c00f2464eee3 128 writeRegister(0x7F, 0x09);
PixArtVY 0:c00f2464eee3 129 writeRegister(0x4F, 0xAF);
PixArtVY 0:c00f2464eee3 130 writeRegister(0x5F, 0x40);
PixArtVY 0:c00f2464eee3 131 writeRegister(0x48, 0x80);
PixArtVY 0:c00f2464eee3 132 writeRegister(0x49, 0x80);
PixArtVY 0:c00f2464eee3 133 writeRegister(0x57, 0x77);
PixArtVY 0:c00f2464eee3 134 writeRegister(0x60, 0x78);
PixArtVY 0:c00f2464eee3 135 writeRegister(0x61, 0x78);
PixArtVY 0:c00f2464eee3 136 writeRegister(0x62, 0x08);
PixArtVY 0:c00f2464eee3 137 writeRegister(0x63, 0x50);
PixArtVY 0:c00f2464eee3 138 writeRegister(0x7F, 0x0A);
PixArtVY 0:c00f2464eee3 139 writeRegister(0x45, 0x60);
PixArtVY 0:c00f2464eee3 140 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 141 writeRegister(0x4D, 0x11);
PixArtVY 0:c00f2464eee3 142 writeRegister(0x55, 0x80);
PixArtVY 0:c00f2464eee3 143 writeRegister(0x74, 0x21);
PixArtVY 0:c00f2464eee3 144 writeRegister(0x75, 0x1F);
PixArtVY 0:c00f2464eee3 145 writeRegister(0x4A, 0x78);
PixArtVY 0:c00f2464eee3 146 writeRegister(0x4B, 0x78);
PixArtVY 0:c00f2464eee3 147 writeRegister(0x44, 0x08);
PixArtVY 0:c00f2464eee3 148 writeRegister(0x45, 0x50);
PixArtVY 0:c00f2464eee3 149 writeRegister(0x64, 0xFF);
PixArtVY 0:c00f2464eee3 150 writeRegister(0x65, 0x1F);
PixArtVY 0:c00f2464eee3 151 writeRegister(0x7F, 0x14);
PixArtVY 0:c00f2464eee3 152 writeRegister(0x65, 0x67);
PixArtVY 0:c00f2464eee3 153 writeRegister(0x66, 0x08);
PixArtVY 0:c00f2464eee3 154 writeRegister(0x63, 0x70);
PixArtVY 0:c00f2464eee3 155 writeRegister(0x7F, 0x15);
PixArtVY 0:c00f2464eee3 156 writeRegister(0x48, 0x48);
PixArtVY 0:c00f2464eee3 157 writeRegister(0x7F, 0x07);
PixArtVY 0:c00f2464eee3 158 writeRegister(0x41, 0x0D);
PixArtVY 0:c00f2464eee3 159 writeRegister(0x43, 0x14);
PixArtVY 0:c00f2464eee3 160 writeRegister(0x4B, 0x0E);
PixArtVY 0:c00f2464eee3 161 writeRegister(0x45, 0x0F);
PixArtVY 0:c00f2464eee3 162 writeRegister(0x44, 0x42);
PixArtVY 0:c00f2464eee3 163 writeRegister(0x4C, 0x80);
PixArtVY 0:c00f2464eee3 164 writeRegister(0x7F, 0x10);
PixArtVY 0:c00f2464eee3 165 writeRegister(0x5B, 0x02);
PixArtVY 0:c00f2464eee3 166 writeRegister(0x7F, 0x07);
PixArtVY 0:c00f2464eee3 167 writeRegister(0x40, 0x41);
PixArtVY 0:c00f2464eee3 168 writeRegister(0x70, 0x00);
PixArtVY 0:c00f2464eee3 169
PixArtVY 0:c00f2464eee3 170 wait_ms(10);
PixArtVY 0:c00f2464eee3 171
PixArtVY 0:c00f2464eee3 172 writeRegister(0x32, 0x44);
PixArtVY 0:c00f2464eee3 173 writeRegister(0x7F, 0x07);
PixArtVY 0:c00f2464eee3 174 writeRegister(0x40, 0x40);
PixArtVY 0:c00f2464eee3 175 writeRegister(0x7F, 0x06);
PixArtVY 0:c00f2464eee3 176 writeRegister(0x62, 0xF0);
PixArtVY 0:c00f2464eee3 177 writeRegister(0x63, 0x00);
PixArtVY 0:c00f2464eee3 178 writeRegister(0x7F, 0x0D);
PixArtVY 0:c00f2464eee3 179 writeRegister(0x48, 0xC0);
PixArtVY 0:c00f2464eee3 180 writeRegister(0x6F, 0xD5);
PixArtVY 0:c00f2464eee3 181 writeRegister(0x7F, 0x00);
PixArtVY 0:c00f2464eee3 182 writeRegister(0x5B, 0xA0);
PixArtVY 0:c00f2464eee3 183 writeRegister(0x4E, 0xA8);
PixArtVY 0:c00f2464eee3 184 writeRegister(0x5A, 0x50);
PixArtVY 0:c00f2464eee3 185 writeRegister(0x40, 0x80);
PixArtVY 0:c00f2464eee3 186 }
PixArtVY 0:c00f2464eee3 187
PixArtVY 0:c00f2464eee3 188
PixArtVY 0:c00f2464eee3 189 //=========================================================================
PixArtVY 0:c00f2464eee3 190 void grabData(void)
PixArtVY 0:c00f2464eee3 191 {
PixArtVY 0:c00f2464eee3 192 deltaX_low = readRegister(0x03); //Grabs data from the proper registers.
PixArtVY 0:c00f2464eee3 193 deltaX_high = (readRegister(0x04)<<8) & 0xFF00; //Grabs data and shifts it to make space to be combined with lower bits.
PixArtVY 0:c00f2464eee3 194 deltaY_low = readRegister(0x05);
PixArtVY 0:c00f2464eee3 195 deltaY_high = (readRegister(0x06)<<8) & 0xFF00;
PixArtVY 0:c00f2464eee3 196
PixArtVY 0:c00f2464eee3 197 deltaX = deltaX_high | deltaX_low; //Combines the low and high bits.
PixArtVY 0:c00f2464eee3 198 deltaY = deltaY_high | deltaY_low;
PixArtVY 0:c00f2464eee3 199 }
PixArtVY 0:c00f2464eee3 200
PixArtVY 0:c00f2464eee3 201
PixArtVY 0:c00f2464eee3 202 //=========================================================================
PixArtVY 0:c00f2464eee3 203 void printData(void)
PixArtVY 0:c00f2464eee3 204 {
PixArtVY 0:c00f2464eee3 205 if((deltaX != 0) || (deltaY != 0)) //If there is deltaX or deltaY movement, print the data.
PixArtVY 0:c00f2464eee3 206 {
PixArtVY 0:c00f2464eee3 207 totalX += deltaX;
PixArtVY 0:c00f2464eee3 208 totalY += deltaY;
PixArtVY 0:c00f2464eee3 209
PixArtVY 0:c00f2464eee3 210 pc.printf("deltaX: %d\t\t\tdeltaY: %d\n\r", deltaX, deltaY); //Prints each individual count of deltaX and deltaY.
PixArtVY 0:c00f2464eee3 211 pc.printf("X-axis Counts: %d\t\tY-axis Counts: %d\n\r", totalX, totalY); //Prints the total movement made during runtime.
PixArtVY 0:c00f2464eee3 212 }
PixArtVY 0:c00f2464eee3 213
PixArtVY 0:c00f2464eee3 214 deltaX = 0; //Resets deltaX and Y values to zero, otherwise previous data is stored until overwritten.
PixArtVY 0:c00f2464eee3 215 deltaY = 0;
PixArtVY 0:c00f2464eee3 216 }