PixArt / Mbed OS 9130_referenceCode

Reference firmware for PixArt's PAT9130EW sensor and evaluation board. "Hello World" and "Library" contain the exact same files. Please import just one of the two into your mBed compiler as a new program and not as a library.

commHeaders/SPIcommFunctions.h@1:efa5e5a1e308, 2018-07-18 (annotated)

Committer:
PixArtVY
Date:
Wed Jul 18 18:33:03 2018 +0000
Revision:
1:efa5e5a1e308
Parent:
0:5a34a4387fb0 
Added Apache License notice.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
PixArtVY 0:5a34a4387fb0 1 //=========================================================================
PixArtVY 0:5a34a4387fb0 2 //Communication pinouts for serial COM port, SPI, and interrupts
PixArtVY 0:5a34a4387fb0 3 //=========================================================================
PixArtVY 0:5a34a4387fb0 4 static Serial pc(USBTX, USBRX); //PC comm
PixArtVY 0:5a34a4387fb0 5 static SPI spi(p23, p24, p25); //mosi, miso, sclk
PixArtVY 0:5a34a4387fb0 6 static DigitalOut cs(p22); //chip select
PixArtVY 0:5a34a4387fb0 7
PixArtVY 0:5a34a4387fb0 8
PixArtVY 0:5a34a4387fb0 9 //=========================================================================
PixArtVY 0:5a34a4387fb0 10 //Variables and arrays used for communications and data storage
PixArtVY 0:5a34a4387fb0 11 //=========================================================================
PixArtVY 0:5a34a4387fb0 12 int8_t deltaX_low, deltaY_low; //Stores the low-bits of movement data.
PixArtVY 0:5a34a4387fb0 13 int16_t deltaX_high, deltaY_high; //Stores the high-bits of movement data.
PixArtVY 0:5a34a4387fb0 14 int16_t deltaX, deltaY; //Stores the combined value of low and high bits.
PixArtVY 0:5a34a4387fb0 15 int16_t totalX, totalY = 0; //Stores the total deltaX and deltaY moved during runtime.
PixArtVY 0:5a34a4387fb0 16 int8_t currentBank; //Stores the current register bank (for tracking/debugging).
PixArtVY 0:5a34a4387fb0 17
PixArtVY 0:5a34a4387fb0 18
PixArtVY 0:5a34a4387fb0 19 //=========================================================================
PixArtVY 0:5a34a4387fb0 20 //Functions used to communicate with the sensor and grab/print data
PixArtVY 0:5a34a4387fb0 21 //=========================================================================
PixArtVY 0:5a34a4387fb0 22 uint8_t readRegister(uint8_t addr);
PixArtVY 0:5a34a4387fb0 23 //This function takes an 8-bit address in the form 0x00 and returns an 8-bit value in the form 0x00.
PixArtVY 0:5a34a4387fb0 24
PixArtVY 0:5a34a4387fb0 25 void writeRegister(uint8_t addr, uint8_t data);
PixArtVY 0:5a34a4387fb0 26 //This function takes an 8-bit address and 8-bit data. Writes the given data to the given address.
PixArtVY 0:5a34a4387fb0 27
PixArtVY 0:5a34a4387fb0 28 void load(const uint8_t array[][2], uint8_t arraySize);
PixArtVY 0:5a34a4387fb0 29 //Takes an array of registers/data (found in registerArrays.h) and their size and writes in all the values.
PixArtVY 0:5a34a4387fb0 30
PixArtVY 0:5a34a4387fb0 31 void grabData(void);
PixArtVY 0:5a34a4387fb0 32 //Grabs the deltaX and deltaY information from the proper registers and formats it into the proper format.
PixArtVY 0:5a34a4387fb0 33
PixArtVY 0:5a34a4387fb0 34 void printData(void);
PixArtVY 0:5a34a4387fb0 35 //Prints the data out to a serial terminal.
PixArtVY 0:5a34a4387fb0 36
PixArtVY 0:5a34a4387fb0 37
PixArtVY 0:5a34a4387fb0 38
PixArtVY 0:5a34a4387fb0 39
PixArtVY 0:5a34a4387fb0 40
PixArtVY 0:5a34a4387fb0 41 //=========================================================================
PixArtVY 0:5a34a4387fb0 42 //Functions definitions
PixArtVY 0:5a34a4387fb0 43 //=========================================================================
PixArtVY 0:5a34a4387fb0 44 uint8_t readRegister(uint8_t addr)
PixArtVY 0:5a34a4387fb0 45 {
PixArtVY 0:5a34a4387fb0 46 cs = 0; //Set chip select low/active
PixArtVY 0:5a34a4387fb0 47 addr = addr & 0x7F; //Set MSB to 0 to indicate read operation
PixArtVY 0:5a34a4387fb0 48 spi.write(addr); //Write the given address
PixArtVY 0:5a34a4387fb0 49 wait_us(1); //Add a tiny delay after sending address for some internal cycle timing.
PixArtVY 0:5a34a4387fb0 50 uint8_t data_read = spi.write(0x00); //Throw dummy byte after sending address to receieve data
PixArtVY 0:5a34a4387fb0 51 cs = 1; //Set chip select back to high/inactive
PixArtVY 0:5a34a4387fb0 52 return data_read; //Returns 8-bit data from register
PixArtVY 0:5a34a4387fb0 53 }
PixArtVY 0:5a34a4387fb0 54
PixArtVY 0:5a34a4387fb0 55
PixArtVY 0:5a34a4387fb0 56 //=========================================================================
PixArtVY 0:5a34a4387fb0 57 void writeRegister(uint8_t addr, uint8_t data)
PixArtVY 0:5a34a4387fb0 58 {
PixArtVY 0:5a34a4387fb0 59 cs = 0; //Set chip select low/active
PixArtVY 0:5a34a4387fb0 60 addr = addr | 0x80; //Set MSB to 1 to indicate write operation
PixArtVY 0:5a34a4387fb0 61 spi.write(addr); //Write the given address
PixArtVY 0:5a34a4387fb0 62 spi.write(data); //Write the given data
PixArtVY 0:5a34a4387fb0 63 cs = 1; //Set chip select back to high/inactive
PixArtVY 0:5a34a4387fb0 64
PixArtVY 0:5a34a4387fb0 65 if(addr == 0x7F) //You can't read register 0x7F for the current bank so we store the value before writing it
PixArtVY 0:5a34a4387fb0 66 {
PixArtVY 0:5a34a4387fb0 67 currentBank = data; //Store the current bank for printing later.
PixArtVY 0:5a34a4387fb0 68 //pc.printf("B:%2X, R:%2X, D:%2X\n\r", currentBank, addr, currentBank);
PixArtVY 0:5a34a4387fb0 69 //Uncomment this line and the other print line below for debugging. Prints every register bank change.
PixArtVY 0:5a34a4387fb0 70 }
PixArtVY 0:5a34a4387fb0 71
PixArtVY 0:5a34a4387fb0 72 else
PixArtVY 0:5a34a4387fb0 73 {
PixArtVY 0:5a34a4387fb0 74 //pc.printf("B:%2X, R:%2X, D:%2X\n\r", currentBank, addr, readRegister(addr));
PixArtVY 0:5a34a4387fb0 75 //Uncomment this line and the other print line above for debugging. Prints every register write operation.
PixArtVY 0:5a34a4387fb0 76 }
PixArtVY 0:5a34a4387fb0 77 }
PixArtVY 0:5a34a4387fb0 78
PixArtVY 0:5a34a4387fb0 79
PixArtVY 0:5a34a4387fb0 80 //=========================================================================
PixArtVY 0:5a34a4387fb0 81 void load(const uint8_t array[][2], uint8_t arraySize)
PixArtVY 0:5a34a4387fb0 82 {
PixArtVY 0:5a34a4387fb0 83 for(uint8_t q = 0; q < arraySize; q++)
PixArtVY 0:5a34a4387fb0 84 {
PixArtVY 0:5a34a4387fb0 85 writeRegister(array[q][0], array[q][1]); //Writes the given array of registers/data.
PixArtVY 0:5a34a4387fb0 86 }
PixArtVY 0:5a34a4387fb0 87 }
PixArtVY 0:5a34a4387fb0 88
PixArtVY 0:5a34a4387fb0 89
PixArtVY 0:5a34a4387fb0 90 //=========================================================================
PixArtVY 0:5a34a4387fb0 91 void grabData(void)
PixArtVY 0:5a34a4387fb0 92 {
PixArtVY 0:5a34a4387fb0 93 deltaX_low = readRegister(0x03); //Grabs data from the proper registers.
PixArtVY 0:5a34a4387fb0 94 deltaY_low = readRegister(0x04);
PixArtVY 0:5a34a4387fb0 95 deltaX_high = (readRegister(0x11)<<8) & 0xFF00; //Grabs data and shifts it to make space to be combined with lower bits.
PixArtVY 0:5a34a4387fb0 96 deltaY_high = (readRegister(0x12)<<8) & 0xFF00;
PixArtVY 0:5a34a4387fb0 97
PixArtVY 0:5a34a4387fb0 98 if(deltaX_high & 0x8000)
PixArtVY 0:5a34a4387fb0 99 deltaX_high |= 0xf000; // 12-bit data convert to 16-bit (two's comp)
PixArtVY 0:5a34a4387fb0 100
PixArtVY 0:5a34a4387fb0 101 if(deltaY_high & 0x8000)
PixArtVY 0:5a34a4387fb0 102 deltaY_high |= 0xf000; // 12-bit data convert to 16-bit (2's comp)
PixArtVY 0:5a34a4387fb0 103
PixArtVY 0:5a34a4387fb0 104 deltaX = deltaX_high | deltaX_low; //Combined the low and high bits.
PixArtVY 0:5a34a4387fb0 105 deltaY = deltaY_high | deltaY_low;
PixArtVY 0:5a34a4387fb0 106 }
PixArtVY 0:5a34a4387fb0 107
PixArtVY 0:5a34a4387fb0 108
PixArtVY 0:5a34a4387fb0 109 //=========================================================================
PixArtVY 0:5a34a4387fb0 110 void printData(void)
PixArtVY 0:5a34a4387fb0 111 {
PixArtVY 0:5a34a4387fb0 112 if((deltaX != 0) || (deltaY != 0)) //If there is deltaX or deltaY movement, print the data.
PixArtVY 0:5a34a4387fb0 113 {
PixArtVY 0:5a34a4387fb0 114 totalX += deltaX;
PixArtVY 0:5a34a4387fb0 115 totalY += deltaY;
PixArtVY 0:5a34a4387fb0 116
PixArtVY 0:5a34a4387fb0 117 pc.printf("deltaX: %d\t\t\tdeltaY: %d\n\r", deltaX, deltaY); //Prints each individual count of deltaX and deltaY.
PixArtVY 0:5a34a4387fb0 118 pc.printf("X-axis Counts: %d\t\tY-axis Counts: %d\n\r", totalX, totalY); //Prints the total movement made during runtime.
PixArtVY 0:5a34a4387fb0 119 }
PixArtVY 0:5a34a4387fb0 120
PixArtVY 0:5a34a4387fb0 121 deltaX = 0; //Resets deltaX and Y values to zero, otherwise previous data is stored until overwritten.
PixArtVY 0:5a34a4387fb0 122 deltaY = 0;
PixArtVY 0:5a34a4387fb0 123 }