PixArt / Mbed OS 9125_referenceCode

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Welcome to the code repository for PixArt's PAT9125EL sensor and evaluation board.

For general information about this product, please visit this product's components page here:
https://os.mbed.com/components/PAT9125EL-Evaluation-Board/

For guides and tips on how to setup and evaluate the PAT9125EL sensor with the Nordic nRF52-DK microcontroller using this reference code, please visit this guide:
https://os.mbed.com/teams/PixArt/code/9125_referenceCode/wiki/Guide-for-nRF52-DK-Platform

For guides and tips on how to setup and evaluate the PAT9125EL sensor with any microcontroller using this reference code, please visit this guide:
https://os.mbed.com/teams/PixArt/code/9125_referenceCode/wiki/Guide-for-Any-Platform

commHeaders/I2CcommFunctions.h@1:4ea157704c58, 2018-02-28 (annotated)

Committer:
PixArtVY
Date:
Wed Feb 28 21:16:23 2018 +0000
Revision:
1:4ea157704c58
Parent:
0:e9cce1154246
Child:
3:979019410df2
Reference firmware for the PAT9125EL 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 program and not as a library.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
PixArtVY 1:4ea157704c58 1 #define I2Cmode //Used to check if the sensor is in I2C mode or SPI mode.
PixArtVY 0:e9cce1154246 2 #define I2C_Slave_ID 0x75 //ONLY WHEN ID PIN IS TIED TO GROUND! ID changes when tied to VDD (0x73) or when left floating (0x79).
PixArtVY 0:e9cce1154246 3
PixArtVY 0:e9cce1154246 4 //=========================================================================
PixArtVY 0:e9cce1154246 5 //Communication pinouts for serial COM port, I2C, and interrupts
PixArtVY 0:e9cce1154246 6 //=========================================================================
PixArtVY 0:e9cce1154246 7 static Serial pc(USBTX, USBRX); //PC comm
PixArtVY 0:e9cce1154246 8 static I2C i2c(p26, p27); //SDA, SCL
PixArtVY 0:e9cce1154246 9
PixArtVY 0:e9cce1154246 10
PixArtVY 0:e9cce1154246 11 //=========================================================================
PixArtVY 0:e9cce1154246 12 //Variables and arrays used for communications and data storage
PixArtVY 0:e9cce1154246 13 //=========================================================================
PixArtVY 0:e9cce1154246 14 int8_t deltaX_low, deltaY_low; //Stores the low-bits of movement data.
PixArtVY 0:e9cce1154246 15 int16_t deltaX_high, deltaY_high; //Stores the high-bits of movement data.
PixArtVY 0:e9cce1154246 16 int16_t deltaX, deltaY; //Stores the combined value of low and high bits.
PixArtVY 0:e9cce1154246 17 int16_t totalX, totalY = 0; //Stores the total deltaX and deltaY moved during runtime.
PixArtVY 0:e9cce1154246 18
PixArtVY 0:e9cce1154246 19
PixArtVY 0:e9cce1154246 20 //=========================================================================
PixArtVY 0:e9cce1154246 21 //Functions used to communicate with the sensor and grab/print data
PixArtVY 0:e9cce1154246 22 //=========================================================================
PixArtVY 0:e9cce1154246 23 uint8_t readRegister(uint8_t addr);
PixArtVY 0:e9cce1154246 24 //This function takes an 8-bit address in the form 0x00 and returns an 8-bit value in the form 0x00.
PixArtVY 0:e9cce1154246 25
PixArtVY 0:e9cce1154246 26 void writeRegister(uint8_t addr, uint8_t data);
PixArtVY 0:e9cce1154246 27 //This function takes an 8-bit address and 8-bit data. Writes the given data to the given address.
PixArtVY 0:e9cce1154246 28
PixArtVY 0:e9cce1154246 29 void load(const uint8_t array[][2], uint8_t arraySize);
PixArtVY 0:e9cce1154246 30 //Takes an array of registers/data (found in registerArrays.h) and their size and writes in all the values.
PixArtVY 0:e9cce1154246 31
PixArtVY 0:e9cce1154246 32 void grabData(void);
PixArtVY 0:e9cce1154246 33 //Grabs the deltaX and deltaY information from the proper registers and formats it into the proper format.
PixArtVY 0:e9cce1154246 34
PixArtVY 0:e9cce1154246 35 void printData(void);
PixArtVY 0:e9cce1154246 36 //Prints the data out to a serial terminal.
PixArtVY 0:e9cce1154246 37
PixArtVY 0:e9cce1154246 38
PixArtVY 0:e9cce1154246 39
PixArtVY 0:e9cce1154246 40
PixArtVY 0:e9cce1154246 41
PixArtVY 0:e9cce1154246 42 //=========================================================================
PixArtVY 0:e9cce1154246 43 //Functions definitions
PixArtVY 0:e9cce1154246 44 //=========================================================================
PixArtVY 0:e9cce1154246 45 uint8_t readRegister(uint8_t addr)
PixArtVY 0:e9cce1154246 46 {
PixArtVY 0:e9cce1154246 47 uint8_t data;
PixArtVY 0:e9cce1154246 48 i2c.write((I2C_Slave_ID << 1), (const char*)&addr, 1, 0); //Send the address to the chip
PixArtVY 0:e9cce1154246 49 wait_us(1);
PixArtVY 0:e9cce1154246 50 i2c.read((I2C_Slave_ID << 1), (char*)&data, 1, 0); //Send the memory address where you want to store the read data
PixArtVY 0:e9cce1154246 51 return(data);
PixArtVY 0:e9cce1154246 52 }
PixArtVY 0:e9cce1154246 53
PixArtVY 0:e9cce1154246 54
PixArtVY 0:e9cce1154246 55 //=========================================================================
PixArtVY 0:e9cce1154246 56 void writeRegister(uint8_t addr, uint8_t data)
PixArtVY 0:e9cce1154246 57 {
PixArtVY 0:e9cce1154246 58 char data_write[2]; //Create an array to store the address/data to pass them at the same time.
PixArtVY 0:e9cce1154246 59 data_write[0] = addr; //Store the address in the first byte
PixArtVY 0:e9cce1154246 60 data_write[1] = data; //Store the data in the second byte
PixArtVY 0:e9cce1154246 61 i2c.write((I2C_Slave_ID << 1), data_write, 2, 0); //Send both over at once
PixArtVY 0:e9cce1154246 62
PixArtVY 0:e9cce1154246 63 pc.printf("R:%2X, D:%2X\n\r", addr, readRegister(addr));
PixArtVY 0:e9cce1154246 64 //Uncomment this line for debugging. Prints every register write operation.
PixArtVY 0:e9cce1154246 65 }
PixArtVY 0:e9cce1154246 66
PixArtVY 0:e9cce1154246 67
PixArtVY 0:e9cce1154246 68 //=========================================================================
PixArtVY 0:e9cce1154246 69 void load(const uint8_t array[][2], uint8_t arraySize)
PixArtVY 0:e9cce1154246 70 {
PixArtVY 0:e9cce1154246 71 for(uint8_t q = 0; q < arraySize; q++)
PixArtVY 0:e9cce1154246 72 {
PixArtVY 0:e9cce1154246 73 writeRegister(array[q][0], array[q][1]); //Writes the given array of registers/data.
PixArtVY 0:e9cce1154246 74 }
PixArtVY 0:e9cce1154246 75 }
PixArtVY 0:e9cce1154246 76
PixArtVY 0:e9cce1154246 77
PixArtVY 0:e9cce1154246 78 //=========================================================================
PixArtVY 0:e9cce1154246 79 void grabData(void)
PixArtVY 0:e9cce1154246 80 {
PixArtVY 0:e9cce1154246 81 deltaX_low = readRegister(0x03); //Grabs data from the proper registers.
PixArtVY 0:e9cce1154246 82 deltaY_low = readRegister(0x04);
PixArtVY 0:e9cce1154246 83 deltaX_high = (readRegister(0x12)<<4) & 0xF00; //Grabs data and shifts it to make space to be combined with lower bits.
PixArtVY 0:e9cce1154246 84 deltaY_high = (readRegister(0x12)<<8) & 0xF00;
PixArtVY 0:e9cce1154246 85
PixArtVY 0:e9cce1154246 86 if(deltaX_high & 0x800)
PixArtVY 0:e9cce1154246 87 deltaX_high |= 0xf000; // 12-bit data convert to 16-bit (two's comp)
PixArtVY 0:e9cce1154246 88
PixArtVY 0:e9cce1154246 89 if(deltaY_high & 0x800)
PixArtVY 0:e9cce1154246 90 deltaY_high |= 0xf000; // 12-bit data convert to 16-bit (2's comp)
PixArtVY 0:e9cce1154246 91
PixArtVY 0:e9cce1154246 92 deltaX = deltaX_high | deltaX_low; //Combined the low and high bits.
PixArtVY 0:e9cce1154246 93 deltaY = deltaY_high | deltaY_low;
PixArtVY 0:e9cce1154246 94 }
PixArtVY 0:e9cce1154246 95
PixArtVY 0:e9cce1154246 96
PixArtVY 0:e9cce1154246 97 //=========================================================================
PixArtVY 0:e9cce1154246 98 void printData(void)
PixArtVY 0:e9cce1154246 99 {
PixArtVY 0:e9cce1154246 100 if((deltaX != 0) || (deltaY != 0)) //If there is deltaX or deltaY movement, print the data.
PixArtVY 0:e9cce1154246 101 {
PixArtVY 0:e9cce1154246 102 totalX += deltaX;
PixArtVY 0:e9cce1154246 103 totalY += deltaY;
PixArtVY 0:e9cce1154246 104
PixArtVY 0:e9cce1154246 105 pc.printf("deltaX: %d\t\t\tdeltaY: %d\n\r", deltaX, deltaY); //Prints each individual count of deltaX and deltaY.
PixArtVY 0:e9cce1154246 106 pc.printf("X-axis Counts: %d\t\t\tY-axis Counts: %d\n\r", totalX, totalY); //Prints the total movement made during runtime.
PixArtVY 0:e9cce1154246 107 }
PixArtVY 0:e9cce1154246 108
PixArtVY 0:e9cce1154246 109 deltaX = 0; //Resets deltaX and Y values to zero, otherwise previous data is stored until overwritten.
PixArtVY 0:e9cce1154246 110 deltaY = 0;
PixArtVY 0:e9cce1154246 111 }