PixArt / Mbed OS 9123_referenceCode

Reference firmware for PixArt's PMT9123 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/I2CcommFunctions.h@1:1d99f5c9581f, 2018-07-18 (annotated)

Committer:
PixArtVY
Date:
Wed Jul 18 18:36:29 2018 +0000
Revision:
1:1d99f5c9581f
Parent:
0:71ff24e8c21e 
Added Apache License notice.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
PixArtVY 0:71ff24e8c21e 1 #define I2C_Slave_ID 0x33 //Slave ID of the PMT9123 sensor.
PixArtVY 0:71ff24e8c21e 2
PixArtVY 0:71ff24e8c21e 3 //=========================================================================
PixArtVY 0:71ff24e8c21e 4 //Communication pinouts for serial COM port, I2C, and interrupts
PixArtVY 0:71ff24e8c21e 5 //=========================================================================
PixArtVY 0:71ff24e8c21e 6 static Serial pc(USBTX, USBRX); //PC comm
PixArtVY 0:71ff24e8c21e 7 static I2C i2c(p26, p27); //SDA, SCL
PixArtVY 0:71ff24e8c21e 8 static DigitalOut NRESET(p25); //Laser diode pin.
PixArtVY 0:71ff24e8c21e 9
PixArtVY 0:71ff24e8c21e 10 //=========================================================================
PixArtVY 0:71ff24e8c21e 11 //Variables and arrays used for communications and data storage
PixArtVY 0:71ff24e8c21e 12 //=========================================================================
PixArtVY 0:71ff24e8c21e 13 int8_t deltaX_low, deltaY_low; //Stores the low-bits of movement data.
PixArtVY 0:71ff24e8c21e 14 int16_t deltaX_high, deltaY_high; //Stores the high-bits of movement data.
PixArtVY 0:71ff24e8c21e 15 int16_t deltaX, deltaY; //Stores the combined value of low and high bits.
PixArtVY 0:71ff24e8c21e 16 int16_t totalX, totalY = 0; //Stores the total deltaX and deltaY moved during runtime.
PixArtVY 0:71ff24e8c21e 17
PixArtVY 0:71ff24e8c21e 18
PixArtVY 0:71ff24e8c21e 19 //=========================================================================
PixArtVY 0:71ff24e8c21e 20 //Functions used to communicate with the sensor and grab/print data
PixArtVY 0:71ff24e8c21e 21 //=========================================================================
PixArtVY 0:71ff24e8c21e 22 uint8_t readRegister(uint8_t addr);
PixArtVY 0:71ff24e8c21e 23 //This function takes an 8-bit address in the form 0x00 and returns an 8-bit value in the form 0x00.
PixArtVY 0:71ff24e8c21e 24
PixArtVY 0:71ff24e8c21e 25 void writeRegister(uint8_t addr, uint8_t data);
PixArtVY 0:71ff24e8c21e 26 //This function takes an 8-bit address and 8-bit data. Writes the given data to the given address.
PixArtVY 0:71ff24e8c21e 27
PixArtVY 0:71ff24e8c21e 28 void startup(void);
PixArtVY 0:71ff24e8c21e 29 //Starts up the sensor to prepare it after receiving power.
PixArtVY 0:71ff24e8c21e 30
PixArtVY 0:71ff24e8c21e 31 void initialize(void);
PixArtVY 0:71ff24e8c21e 32 //Runs the initialization sequence for the sensor.
PixArtVY 0:71ff24e8c21e 33
PixArtVY 0:71ff24e8c21e 34 void load(const uint8_t array[][2], uint8_t arraySize);
PixArtVY 0:71ff24e8c21e 35 //Takes an array of registers/data (found in registerArrays.h) and their size and writes in all the values.
PixArtVY 0:71ff24e8c21e 36
PixArtVY 0:71ff24e8c21e 37 void grabData(void);
PixArtVY 0:71ff24e8c21e 38 //Grabs the deltaX and deltaY information from the proper registers and formats it into the proper format.
PixArtVY 0:71ff24e8c21e 39
PixArtVY 0:71ff24e8c21e 40 void printData(void);
PixArtVY 0:71ff24e8c21e 41 //Prints the data out to a serial terminal.
PixArtVY 0:71ff24e8c21e 42
PixArtVY 0:71ff24e8c21e 43
PixArtVY 0:71ff24e8c21e 44
PixArtVY 0:71ff24e8c21e 45
PixArtVY 0:71ff24e8c21e 46
PixArtVY 0:71ff24e8c21e 47 //=========================================================================
PixArtVY 0:71ff24e8c21e 48 //Functions definitions
PixArtVY 0:71ff24e8c21e 49 //=========================================================================
PixArtVY 0:71ff24e8c21e 50 uint8_t readRegister(uint8_t addr)
PixArtVY 0:71ff24e8c21e 51 {
PixArtVY 0:71ff24e8c21e 52 uint8_t data;
PixArtVY 0:71ff24e8c21e 53
PixArtVY 0:71ff24e8c21e 54 i2c.write((I2C_Slave_ID << 1), (const char*)&addr, 1, 0); //Send the address to the chip
PixArtVY 0:71ff24e8c21e 55 wait_us(1);
PixArtVY 0:71ff24e8c21e 56 i2c.read((I2C_Slave_ID << 1), (char*)&data, 1, 0); //Send the memory address where you want to store the read data
PixArtVY 0:71ff24e8c21e 57 return(data);
PixArtVY 0:71ff24e8c21e 58 }
PixArtVY 0:71ff24e8c21e 59
PixArtVY 0:71ff24e8c21e 60
PixArtVY 0:71ff24e8c21e 61 //=========================================================================
PixArtVY 0:71ff24e8c21e 62 void writeRegister(uint8_t addr, uint8_t data)
PixArtVY 0:71ff24e8c21e 63 {
PixArtVY 0:71ff24e8c21e 64 char data_write[2]; //Create an array to store the address/data to pass them at the same time.
PixArtVY 0:71ff24e8c21e 65
PixArtVY 0:71ff24e8c21e 66 data_write[0] = addr; //Store the address in the first byte
PixArtVY 0:71ff24e8c21e 67 data_write[1] = data; //Store the data in the second byte
PixArtVY 0:71ff24e8c21e 68 i2c.write((I2C_Slave_ID << 1), data_write, 2, 0); //Send both over at once
PixArtVY 0:71ff24e8c21e 69
PixArtVY 0:71ff24e8c21e 70 pc.printf("R:%2X, D:%2X\n\r", addr, readRegister(addr));
PixArtVY 0:71ff24e8c21e 71 //Uncomment this line for debugging. Prints every register write operation.
PixArtVY 0:71ff24e8c21e 72 }
PixArtVY 0:71ff24e8c21e 73
PixArtVY 0:71ff24e8c21e 74
PixArtVY 0:71ff24e8c21e 75 //=========================================================================
PixArtVY 0:71ff24e8c21e 76 void startup(void)
PixArtVY 0:71ff24e8c21e 77 {
PixArtVY 0:71ff24e8c21e 78 NRESET = 0; //Drive NRESET low for 20us to reset the device.
PixArtVY 0:71ff24e8c21e 79 wait_us(20);
PixArtVY 0:71ff24e8c21e 80 NRESET = 1;
PixArtVY 0:71ff24e8c21e 81 wait_ms(1.5);
PixArtVY 0:71ff24e8c21e 82 }
PixArtVY 0:71ff24e8c21e 83
PixArtVY 0:71ff24e8c21e 84
PixArtVY 0:71ff24e8c21e 85 //=========================================================================
PixArtVY 0:71ff24e8c21e 86 void initialize(void)
PixArtVY 0:71ff24e8c21e 87 {
PixArtVY 0:71ff24e8c21e 88 writeRegister(0x41, 0xBA); //Disables register write protection.
PixArtVY 0:71ff24e8c21e 89 wait_us(300); //Delay 300us for timing purposes. (necessary)
PixArtVY 0:71ff24e8c21e 90
PixArtVY 0:71ff24e8c21e 91 writeRegister(0x1D, 0x00); //Clears the "what mode are we in" register.
PixArtVY 0:71ff24e8c21e 92 wait_ms(10); //Delay 10ms for timing purposes. (necessary)
PixArtVY 0:71ff24e8c21e 93
PixArtVY 0:71ff24e8c21e 94 readRegister(0x02); //Clears motion bit and motion storage registers.
PixArtVY 0:71ff24e8c21e 95 readRegister(0x03);
PixArtVY 0:71ff24e8c21e 96 readRegister(0x04);
PixArtVY 0:71ff24e8c21e 97 readRegister(0x05);
PixArtVY 0:71ff24e8c21e 98 }
PixArtVY 0:71ff24e8c21e 99
PixArtVY 0:71ff24e8c21e 100
PixArtVY 0:71ff24e8c21e 101 //=========================================================================
PixArtVY 0:71ff24e8c21e 102 void load(const uint8_t array[][2], uint8_t arraySize)
PixArtVY 0:71ff24e8c21e 103 {
PixArtVY 0:71ff24e8c21e 104 for(uint8_t q = 0; q < arraySize; q++)
PixArtVY 0:71ff24e8c21e 105 {
PixArtVY 0:71ff24e8c21e 106 writeRegister(array[q][0], array[q][1]); //Writes the given array of registers/data.
PixArtVY 0:71ff24e8c21e 107 }
PixArtVY 0:71ff24e8c21e 108 }
PixArtVY 0:71ff24e8c21e 109
PixArtVY 0:71ff24e8c21e 110
PixArtVY 0:71ff24e8c21e 111 //=========================================================================
PixArtVY 0:71ff24e8c21e 112 void grabData(void)
PixArtVY 0:71ff24e8c21e 113 {
PixArtVY 0:71ff24e8c21e 114 deltaX_low = readRegister(0x03); //Grabs data from the proper registers.
PixArtVY 0:71ff24e8c21e 115 deltaY_low = readRegister(0x04);
PixArtVY 0:71ff24e8c21e 116 deltaX_high = (readRegister(0x05)<<4) & 0xF00; //Grabs data and shifts it to make space to be combined with lower bits.
PixArtVY 0:71ff24e8c21e 117 deltaY_high = (readRegister(0x05)<<8) & 0xF00;
PixArtVY 0:71ff24e8c21e 118
PixArtVY 0:71ff24e8c21e 119 if(deltaX_high & 0x800)
PixArtVY 0:71ff24e8c21e 120 deltaX_high |= 0xf000; // 12-bit data convert to 16-bit (two's comp)
PixArtVY 0:71ff24e8c21e 121
PixArtVY 0:71ff24e8c21e 122 if(deltaY_high & 0x800)
PixArtVY 0:71ff24e8c21e 123 deltaY_high |= 0xf000; // 12-bit data convert to 16-bit (2's comp)
PixArtVY 0:71ff24e8c21e 124
PixArtVY 0:71ff24e8c21e 125 deltaX = deltaX_high | deltaX_low; //Combined the low and high bits.
PixArtVY 0:71ff24e8c21e 126 deltaY = deltaY_high | deltaY_low;
PixArtVY 0:71ff24e8c21e 127 }
PixArtVY 0:71ff24e8c21e 128
PixArtVY 0:71ff24e8c21e 129
PixArtVY 0:71ff24e8c21e 130 //=========================================================================
PixArtVY 0:71ff24e8c21e 131 void printData(void)
PixArtVY 0:71ff24e8c21e 132 {
PixArtVY 0:71ff24e8c21e 133 if((deltaX != 0) || (deltaY != 0)) //If there is deltaX or deltaY movement, print the data.
PixArtVY 0:71ff24e8c21e 134 {
PixArtVY 0:71ff24e8c21e 135 totalX += deltaX;
PixArtVY 0:71ff24e8c21e 136 totalY += deltaY;
PixArtVY 0:71ff24e8c21e 137
PixArtVY 0:71ff24e8c21e 138 pc.printf("deltaX: %d\t\t\tdeltaY: %d\n\r", deltaX, deltaY); //Prints each individual count of deltaX and deltaY.
PixArtVY 0:71ff24e8c21e 139 pc.printf("X-axis Counts: %d\t\tY-axis Counts: %d\n\r", totalX, totalY); //Prints the total movement made during runtime.
PixArtVY 0:71ff24e8c21e 140 }
PixArtVY 0:71ff24e8c21e 141
PixArtVY 0:71ff24e8c21e 142 deltaX = 0; //Resets deltaX and Y values to zero, otherwise previous data is stored until overwritten.
PixArtVY 0:71ff24e8c21e 143 deltaY = 0;
PixArtVY 0:71ff24e8c21e 144 }