WS2812 RGB and BNO055 IMU PIC Projects

This weekend I spent my Friday afternoon and Saturday at the NW Hobby Expo; talk about an intense desire to get another hobby.

RC Plane NW Hobby Expo

Oh wait… oops; don’t tell me wife 😉 Should be here tomorrow. A little small guy to get me started.

hk_order201602

I was out helping a friend sell 3D printers and interest people into joining our Makerspace.. mission success? I don’t know we’ll see at the next open house.

The makerspace has kept me busy every moment I haven’t been spending with my little man.. thankfully my makerspace activities have been more to my desires.. I developed a little code to run WS2812 LED drivers for a PIC… why we used a PIC (my fav) I’m unsure.. these maker-folks are all Arduino… I borrow a board and took a look. It’s cute.. micros with training wheels. Here is some basic code to generate colors.. maybe it’ll cut your dev time down on a real project.
RGB WS2812 PIC


/*
 * File:   main.c
 * Author: Charles M Ihler
 * Contact at: http://iradan.com
 *
 * Created on Janurary 1, 2015
 *
 * Target Device:
 * 18F14K22 
 *
 * Project: RGB Resistor Clock
 *
 
 * Version:
 * 0.1  Configuration, with reset test
 * 0.2  Send a single color to 1 neopixel (WS2811/WS2812)
 *
 */
#ifndef _XTAL_FREQ
#define _XTAL_FREQ 4000000 //16Mhz FRC internal osc
#define __delay_us(x) _delay((unsigned long)((x)*(_XTAL_FREQ/16000000.0)))
#define __delay_ms(x) _delay((unsigned long)((x)*(_XTAL_FREQ/16000.0)))
#endif

#define CHECK_BIT(var,pos) ((var) & (1<<(pos)))

#include 
#include 
#include 
#include 


//config bits
#pragma config FOSC=IRC, WDTEN=OFF, PWRTEN=OFF, MCLRE=ON, CP0=OFF, CP1=OFF, BOREN=ON
#pragma config STVREN=ON, LVP=OFF, HFOFST=OFF, IESO=OFF, FCMEN=OFF

#define _XTAL_FREQ 64000000 //defined for delay

/*
 * Variables
 */

    int     device_present;             // 1 = 1-wire device on 1-wire bus
    int     i, x, y, temp, an4_value;               //
    long int    decm;
    int     itxdata, txdata;            //int RS232 tx data
    char    rxbuff[10], z[1], buf[4];                 //buffer for T-sense 1-wire device
    float    temperature, f, d;
    volatile unsigned int uart_data;    // use 'volatile' qualifer as this is changed in ISR

/*
 *  Functions
 */

    void interrupt ISR() {

    if (PIR1bits.RCIF)          // see if interrupt caused by incoming data .. unused currently
    {
        uart_data = RCREG;     // read the incoming data
        PIR1bits.RCIF = 0;      // clear interrupt flag
                                //
    }
    // I left this timer interrupt if I needed it later. This is unused.
    if (PIR1bits.TMR1IF)
    {
        //T1CONbits.TMR1ON = 0;
        
        PIR1bits.TMR1IF = 0;
        //T1CONbits.TMR1ON = 1;

    }
}


     void __delay_10ms(unsigned char n)     //__delay functions built-in can't be used for much at this speed... so!
 {
     while (n-- != 0) {
         __delay_ms(10);
     }
 }


void uart_send (unsigned int mydata_byte) {      //bytes

    while(!TXSTAbits.TRMT);    // make sure buffer full bit is high before transmitting
    TXREG = mydata_byte;       // transmit data
}

void write_uart(const char *txt)                //strings
{
                                //this send a string to the TX buffer
                                //one character at a time
       while(*txt)
       uart_send(*txt++);
}

//This code if from Microchip but is unused currently.
void uart_send_hex_ascii(unsigned char display_data)
{

	//unsigned char temp;
	//temp = ((display_data & 0xF0)>>4);
	//if (temp <= 0x09)
	//	Putchar(temp+'0');
	//else
	//	Putchar(temp+'0'+0x07);
        //
	//temp = display_data & 0x0F;
	//if (temp <= 0x09)
	//	Putchar(temp+'0');
	//else
	//	Putchar(temp+'0'+0x07);

	//Putchar('\r');
	//Putchar('\n');
}

void serial_init(void)
{

    // calculate values of SPBRGL and SPBRGH based on the desired baud rate
    //
    // For 8 bit Async mode with BRGH=0: Desired Baud rate = Fosc/64([SPBRGH:SPBRGL]+1)
    // For 8 bit Async mode with BRGH=1: Desired Baud rate = Fosc/16([SPBRGH:SPBRGL]+1)



    TXSTAbits.BRGH=1;       // select low speed Baud Rate (see baud rate calcs below)
    TXSTAbits.TX9=0;        // select 8 data bits
    TXSTAbits.TXEN=1;     // enable transmit
    BAUDCONbits.BRG16=0;

    RCSTAbits.SPEN=1;       // serial port is enabled
    RCSTAbits.RX9=0;        // select 8 data bits
    RCSTAbits.CREN=1;       // receive enabled


    SPBRG=25;               //38,400bps-ish
                            //BRG16=0, 7=31.25k, 25=9.615k

    PIR1bits.RCIF=0;        // make sure receive interrupt flag is clear
    PIE1bits.RCIE=1;        // enable UART Receive interrupt


         __delay_ms(10);        // give time for voltage levels on board to settle

}

void send_low(void){
    LATCbits.LATC0 = 1;
    _delay(5);
    LATCbits.LATC0 = 0;
    _delay(11);
}

void send_high(void){
    LATCbits.LATC0 = 1;
    _delay(11);
    LATCbits.LATC0 = 0;
    _delay(8);
}


void init_io(void) {
    ANSEL = 0x00;         
    ANSELH = 0x00;

    TRISAbits.TRISA0 = 1; // PGD
    TRISAbits.TRISA1 = 1; // PGC
    TRISAbits.TRISA2 = 0; // output
    TRISAbits.TRISA4 = 1; // OSC
    TRISAbits.TRISA5 = 1; // OSC



    TRISBbits.TRISB4 = 0; // output
    TRISBbits.TRISB5 = 1; // input (RX UART)
    TRISBbits.TRISB6 = 0; // output
    TRISBbits.TRISB7 = 0; // output (TX UART)

    LATC = 0x00;

    TRISCbits.TRISC0 = 0; // WG2812 Output
    TRISCbits.TRISC1 = 1; // 
    TRISCbits.TRISC2 = 0; // 
    TRISCbits.TRISC3 = 0; // 
    TRISCbits.TRISC4 = 0; // 
    TRISCbits.TRISC5 = 0; // output
    TRISCbits.TRISC6 = 1; // input
    TRISCbits.TRISC7 = 1; // input

}

void send_black (void) {
        send_low(); //G1
        send_low(); //G2
        send_low(); //G3
        send_low(); //G4
        send_low(); //G5
        send_low(); //G6
        send_low(); //G7
        send_low(); //G8
        
        send_low(); //R1
        send_low(); //R2
        send_low(); //R3
        send_low(); //R4
        send_low(); //R5
        send_low(); //R6
        send_low(); //R7
        send_low(); //R8
        
        send_low(); //B1 00000 0000
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_brown (void) {
        send_low(); //G1 64
        send_low(); //G2 
        send_high(); //G3 
        send_low(); //G4 
        send_low(); //G5 
        send_low(); //G6 
        send_low(); //G7 
        send_low(); //G8 
        
        send_low(); //R1 128
        send_high(); //R2 0
        send_low(); //R3 1
        send_low(); //R4 0
        send_low(); //R5 0
        send_low(); //R6 1
        send_low(); //R7 0
        send_low(); //R8 1      
  
        send_low(); //B1 0
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_orange (void) {
        send_high(); //G1 165 / 1010 0101
        send_low(); //G2 
        send_high(); //G3 
        send_low(); //G4 
        send_low(); //G5 
        send_high(); //G6 
        send_low(); //G7 
        send_high(); //G8 
        
        send_high(); //R1 1111 1111
        send_high(); //R2 
        send_high(); //R3 
        send_high(); //R4 
        send_high(); //R5 
        send_high(); //R6 
        send_high(); //R7 
        send_high(); //R8       
  
        send_low(); //B1 00000 0000
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}


void send_yellow (void) {
        send_high(); //G1 255 / 1111 1111
        send_high(); //G2 
        send_high(); //G3 
        send_high(); //G4 
        send_high(); //G5 
        send_high(); //G6 
        send_high(); //G7 
        send_high(); //G8 
        
        send_high(); //R1 1111 1111
        send_high(); //R2 
        send_high(); //R3 
        send_high(); //R4 
        send_high(); //R5 
        send_high(); //R6 
        send_high(); //R7 
        send_high(); //R8       
  
        send_low(); //B1 00000 0000
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_blue (void) {
        send_low(); //G1
        send_low(); //G2
        send_low(); //G3
        send_low(); //G4
        send_low(); //G5
        send_low(); //G6
        send_low(); //G7
        send_low(); //G8
        
        send_low(); //R1
        send_low(); //R2
        send_low(); //R3
        send_low(); //R4
        send_low(); //R5
        send_low(); //R6
        send_low(); //R7
        send_low(); //R8        
  
        send_high(); //B1
        send_high(); //B2
        send_high(); //B3
        send_high(); //B4
        send_high(); //B5
        send_high(); //B6
        send_high(); //B7
        send_high(); //B8
}

void send_green (void) {
        send_high(); //G1
        send_high(); //G2
        send_high(); //G3
        send_high(); //G4
        send_high(); //G5
        send_high(); //G6
        send_high(); //G7
        send_high(); //G8
        
        send_low(); //R1
        send_low(); //R2
        send_low(); //R3
        send_low(); //R4
        send_low(); //R5
        send_low(); //R6
        send_low(); //R7
        send_low(); //R8        
  
        send_low(); //B1
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_grey (void) {
        send_low(); //G1
        send_low(); //G2
        send_high(); //G3
        send_low(); //G4
        send_low(); //G5
        send_low(); //G6
        send_low(); //G7
        send_low(); //G8
        
        send_low(); //R1
        send_low(); //R2
        send_high(); //R3
        send_low(); //R4
        send_low(); //R5
        send_low(); //R6
        send_low(); //R7
        send_low(); //R8        
  
        send_low(); //B1
        send_low(); //B2
        send_high(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_violet (void) {
        send_low(); //G1
        send_low(); //G2
        send_low(); //G3
        send_low(); //G4
        send_low(); //G5
        send_low(); //G6
        send_low(); //G7
        send_low(); //G8
        
        send_high(); //R1
        send_high(); //R2
        send_high(); //R3
        send_high(); //R4
        send_high(); //R5
        send_high(); //R6
        send_high(); //R7
        send_high(); //R8        
  
        send_high(); //B1
        send_high(); //B2
        send_high(); //B3
        send_high(); //B4
        send_high(); //B5
        send_high(); //B6
        send_high(); //B7
        send_high(); //B8
}

void send_red (void) {
        send_low(); //G1
        send_low(); //G2
        send_low(); //G3
        send_low(); //G4
        send_low(); //G5
        send_low(); //G6
        send_low(); //G7
        send_low(); //G8
        
        send_high(); //R1
        send_high(); //R2
        send_high(); //R3
        send_high(); //R4
        send_high(); //R5
        send_high(); //R6
        send_high(); //R7
        send_high(); //R8        
  
        send_low(); //B1
        send_low(); //B2
        send_low(); //B3
        send_low(); //B4
        send_low(); //B5
        send_low(); //B6
        send_low(); //B7
        send_low(); //B8
}

void send_white (void) {
        send_high(); //G1 255 / 1111 1111
        send_high(); //G2 
        send_high(); //G3 
        send_high(); //G4 
        send_high(); //G5 
        send_high(); //G6 
        send_high(); //G7 
        send_high(); //G8 
        
        send_high(); //R1 1111 1111
        send_high(); //R2 
        send_high(); //R3 
        send_high(); //R4 
        send_high(); //R5 
        send_high(); //R6 
        send_high(); //R7 
        send_high(); //R8       
  
        send_high(); //B1
        send_high(); //B2
        send_high(); //B3
        send_high(); //B4
        send_high(); //B5
        send_high(); //B6
        send_high(); //B7
        send_high(); //B8
}


int main(void) {

    init_io();

    // set up oscillator control register, using internal OSC at 16MHz.
    OSCCONbits.IRCF = 0x07; //set OSCCON IRCF bits to select OSC frequency 16MHz
    OSCCONbits.SCS = 0x00; //set the SCS bits to select internal oscillator block
    OSCTUNEbits.PLLEN = 0x01;   //x4 PLL
    //RCONbits.IPEN = 0;          //disable priority levels

    INTCONbits.PEIE = 1;        // Enable peripheral interrupt
    INTCONbits.GIE = 1;         // enable global interrupt

    temp = 0x10000000;

    while (1) {
        //RGB high bit first
        //if (CHECK_BIT(temp, 0)) {
        //send_high(); //G1    
        //} else {
        //send_low(); //G1    
        //}
        
        send_brown();
        send_orange();
        send_yellow();
        
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);        
        
        send_black();    //1st LED
        send_grey();   //2nd LED
        send_white();     //3rd LED

        
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);    
        
        //send_green();
        //send_violet();
        //send_grey();
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10);
        __delay_ms(10); 
        __delay_us(100);

    }
    return (EXIT_SUCCESS);
}

It’s very very dirty and there is some un-used stuff… but it was a quick hack based on old code and I didn’t optimize the delays at all.
… This is work in progress for a resistor color code clock. I’ll obviously need to switch to a crystal, etc.

I also threw together some basic test code for the 9DOF BNO055 IMU. I bought one just for kicks in case I want to add it to my SRS Pop Can Challenge competition robot. I volunteered for the job left over on our makerspace robot group project… because power systems are a bit of a snooze, and I’m pretty much done, I decided to make my own. It won’t win (because I’m not going for all the points) but it’ll be another robot on the field. Here is some cBode to get you started if you’re interested… I used the Adafruit BOB.. pretty cool and they broke out just enough stuff it seems. I tried it with the UART interface first for kicks.. but then switched to I2C.


/*
 * File:   main.c
 * Author: Charles M Ihler
 * Contact at: http://iradan.com
 *
 * Created on February 8, 2014, 11:39 AM
 *
 * Target Device:
 * 18F14K22 on Tautic 20 pin dev board
 *
 * Project: IMU for PCC
 *
 *
 * Version:
 * 0.1  IO Confoiguration RS232/TX/I2C
 * 0.2  Test BNO055 by UART
 * 0.3  Dump UART interface and get cal status via I2C and send to UART 
 *
 */
#ifndef _XTAL_FREQ
#define _XTAL_FREQ 16000000 //4Mhz FRC internal osc
#define __delay_us(x) _delay((unsigned long)((x)*(_XTAL_FREQ/16000000.0)))
#define __delay_ms(x) _delay((unsigned long)((x)*(_XTAL_FREQ/16000.0)))
#endif

#include 
#include 
#include 
#include 


//config bits
#pragma config FOSC=IRC, WDTEN=OFF, PWRTEN=OFF, MCLRE=ON, CP0=OFF, CP1=OFF, BOREN=ON
#pragma config STVREN=ON, LVP=OFF, HFOFST=OFF, IESO=OFF, FCMEN=OFF

/*
 * Variables
 */

#define r_device_address  0x51 // BNO055 Default Address
#define w_device_address  0x50 // BNO055 Default Address

    unsigned int ACK_bit;
    int i;
    unsigned char byte, tempbyte1, tempbyte2;

    int     w0,w1,w2,w3,w4;     //confirguration words
    int     present;              //device present
    //int     itxdata;            //int RS232 tx data
    //char    buf[10];            //buff for iota
    volatile unsigned int uart_data;    // use 'volatile' qualifer as this is changed in ISR

/*
 *  Functions
 */

    void interrupt ISR() {

    if (PIR1bits.RCIF)          // see if interrupt caused by incoming data
    {
        uart_data = RCREG;     // read the incoming data
        if (uart_data == 0xBB)
        {
            LATAbits.LA0 = 1;
            present = 1;
        }
        PIR1bits.RCIF = 0;      // clear interrupt flag
                                //
    }
    if (INTCONbits.T0IF)
    {
        //LATAbits.LATA0 = 1;
        INTCONbits.T0IF = 0;
    }

}

void __delay_10ms(unsigned char n)     //__delay functions built-in can't be used for much at this speed... so!
 {
     while (n-- != 0) {
         __delay_ms(10);
     }
 }
     
void uart_tx(unsigned int mydata_byte) {
    while(!TXSTAbits.TRMT);    // make sure buffer full bit is high before transmitting
    TXREG = mydata_byte;       // transmit data
}

void write_uart(const char *txt){
    while(*txt != 0) uart_tx(*txt++);     //this send a string to the TX buffer
                                            //one character at a time
}

void serial_init(void)
{

    // calculate values of SPBRGL and SPBRGH based on the desired baud rate
    //
    // For 8 bit Async mode with BRGH=0: Desired Baud rate = Fosc/64([SPBRGH:SPBRGL]+1)
    // For 8 bit Async mode with BRGH=1: Desired Baud rate = Fosc/16([SPBRGH:SPBRGL]+1)



    TXSTAbits.BRGH=1;       // 
    TXSTAbits.TX9=0;        // select 8 data bits
    TXSTAbits.TXEN = 1;     // enable transmit


    RCSTAbits.SPEN=1;       // serial port is enabled
    RCSTAbits.RX9=0;        // select 8 data bits
    RCSTAbits.CREN=1;       // receive enabled

    SPBRG=103;               //

    PIR1bits.RCIF=0;        // make sure receive interrupt flag is clear
    PIE1bits.RCIE=1;        // enable UART Receive interrupt
    INTCONbits.PEIE = 1;    // Enable peripheral interrupt
    INTCONbits.GIE = 1;     // enable global interrupt
    INTCONbits.T0IE = 0;

         __delay_10ms(5);        // give time for voltage levels on board to settle
}


void init_io(void) {
    TRISAbits.TRISA0 = 0; // output
    TRISAbits.TRISA1 = 1; // input
    TRISAbits.TRISA2 = 1; // 
    TRISAbits.TRISA4 = 1; // 
    TRISAbits.TRISA5 = 1; // 
    
    ANSEL = 0x00;         // no A/D
    ANSELH = 0x00;

    TRISBbits.TRISB4 = 1; // RB4 I2C SDA, has to be set as an input
    TRISBbits.TRISB5 = 1; // RB5 = nc
    TRISBbits.TRISB6 = 1; // RB6 I2C SCLK, has to be set as an input
    TRISBbits.TRISB7 = 0; // RS232 TX

    WPUBbits.WPUB4 = 0x01;        //PORT B WEAK PULL UPS
    WPUBbits.WPUB6 = 0x01;
    
    TRISCbits.TRISC0 = 1; // 
    TRISCbits.TRISC1 = 1; // input
    TRISCbits.TRISC2 = 1; // 
    TRISCbits.TRISC3 = 0; // 
    TRISCbits.TRISC4 = 0; // 
    TRISCbits.TRISC5 = 0; // 
    TRISCbits.TRISC6 = 1; // input
    TRISCbits.TRISC7 = 1; // input

    __delay_10ms(10);   //let voltage settle
    
    //write_uart("RESET\n");         // transmit some data

}

void I2C_ACK(void)
{
   PIR1bits.SSPIF=0;          // clear SSP interrupt bit
   SSPCON2bits.ACKDT=0;        // clear the Acknowledge Data Bit - this means we are sending an Acknowledge or 'ACK'
   SSPCON2bits.ACKEN=1;        // set the ACK enable bit to initiate transmission of the ACK bit to the serial eeprom
   while(!PIR1bits.SSPIF);    // Wait for interrupt flag to go high indicating transmission is complete
}

void Send_I2C_Data(unsigned int databyte)
{
    PIR1bits.SSPIF=0;          // clear SSP interrupt bit
    SSPBUF = databyte;              // send databyte
    while(!PIR1bits.SSPIF);    // Wait for interrupt flag to go high indicating transmission is complete
}

unsigned char RX_I2C_Data (void)
{
    RCEN = 1;               // 
    while( RCEN ) continue;
    while( !BF ) continue;
    byte = SSPBUF;
   return byte;
}

void I2C_Control_Write(void)
{
    PIR1bits.SSPIF=0;          // clear SSP interrupt bit
    SSPBUF = w_device_address;             // send the control byte (90 TCN75, EF BMP085)
    while(!PIR1bits.SSPIF)     // Wait for interrupt flag to go high indicating transmission is complete
        {
        i = 1;
          // place to add a breakpoint if needed
        }
    PIR1bits.SSPIF=0;

}

void I2C_Control_Read(void)
{
    PIR1bits.SSPIF=0;          // clear SSP interrupt bit
    SSPBUF = r_device_address;   // send the control byte (90 TCN75, EF BMP085)
    while(!PIR1bits.SSPIF)     // Wait for interrupt flag to go high indicating transmission is complete
        {
        i = 1;
          // place to add a breakpoint if needed
        }
    PIR1bits.SSPIF=0;
   }


void I2C_Start_Bit(void)
{
    PIR1bits.SSPIF=0;          // clear SSP interrupt bit
    SSPCON2bits.SEN=1;          // send start bit
    while(!PIR1bits.SSPIF)    // Wait for the SSPIF bit to go back high before we load the data buffer
        {
        i = 1;
        }
    PIR1bits.SSPIF=0;
}

void I2C_check_idle()
{
    unsigned char byte1; // R/W status: Is a transfer in progress?
    unsigned char byte2; // Lower 5 bits: Acknowledge Sequence, Receive, STOP, Repeated START, START

    do
    {
        byte1 = SSPSTAT & 0x04;
        byte2 = SSPCON2 & 0x1F;
    } while( byte1 | byte2 );
}
/*
 * Send the repeated start message and wait repeated start to finish.
 */
void I2C_restart()
{
    I2C_check_idle();
    RSEN = 1; // Reinitiate start
    while( RSEN ) continue;
}

void I2C_Stop_Bit(void)
{
    PIR1bits.SSPIF=0;          // clear SSP interrupt bit
    SSPCON2bits.PEN=1;          // send stop bit
    while(!PIR1bits.SSPIF)
    {
        i = 1;
        // Wait for interrupt flag to go high indicating transmission is complete
    }
}

void I2C_NAK(void)
{
    PIR1bits.SSPIF=0;           // clear SSP interrupt bit
    SSPCON2bits.ACKDT=1;        // set the Acknowledge Data Bit- this means we are sending a No-Ack or 'NAK'
    SSPCON2bits.ACKEN=1;        // set the ACK enable bit to initiate transmission of the ACK bit to the serial eeprom
    while(!PIR1bits.SSPIF)     // Wait for interrupt flag to go high indicating transmission is complete
    {
        i = 1;
    }
}

void read_imu_status(void){
    
    I2C_Start_Bit();                    // send start bit
    I2C_Control_Write();                // send control byte with read set
    Send_I2C_Data(0x00);                // register

    I2C_restart();                      // restart

    I2C_Control_Read();
    RX_I2C_Data();                      // read high
    tempbyte1=byte;
//    I2C_ACK();                          // ACK
//    RX_I2C_Data();                      // read low
//    tempbyte2=byte;
    I2C_NAK();                          // NAK
    //I2C_restart();
    I2C_Stop_Bit();                     // Send Stop Bit

    uart_tx(tempbyte1);               //send data off raw by UART

}

void read_imu_cal_status(void){
    
    I2C_Start_Bit();                    // send start bit
    I2C_Control_Write();                // send control byte with read set
    Send_I2C_Data(0x35);                // register

    I2C_restart();                      // restart

    I2C_Control_Read();
    RX_I2C_Data();                      // read high
    tempbyte1=byte;
//    I2C_ACK();                          // ACK
//    RX_I2C_Data();                      // read low
//    tempbyte2=byte;
    I2C_NAK();                          // NAK
    //I2C_restart();
    I2C_Stop_Bit();                     // Send Stop Bit

    uart_tx(tempbyte1);               //send data off raw by UART

}

void write_imu_9DOF(void)
{

    I2C_Start_Bit();                    // send start bit
    I2C_Control_Write();                // send control byte
    Send_I2C_Data(0x3D);                // address
    Send_I2C_Data(0x1C);                // enable 9dof
    I2C_Stop_Bit();

}

void i2c_muck(void)
{

    I2C_Start_Bit();                     // send start bit
    I2C_Control_Write();                  // send control byte with read set

    //if (!SSP1CON2bits.ACKSTAT)
    //LATCbits.LATC1 = 0;                   //device /ACked?

    Send_I2C_Data(0x01);                //pointer
    Send_I2C_Data(0xE1);                //1 shot, 12bit res
    I2C_Stop_Bit();

    __delay_10ms(50);                     //wait for conversion

    I2C_Start_Bit();                     // send start bit
    I2C_Control_Write();                  // send control byte with read set

    //    if (!SSP1CON2bits.ACKSTAT)
//    LATCbits.LATC1 = 0;

    Send_I2C_Data(0x00);                //pointer

    I2C_restart();                      //restart
    I2C_Control_Read();
    RX_I2C_Data();                      //read high
    tempbyte1=byte;
    I2C_ACK();                          //ACK
    RX_I2C_Data();                      //read low
    tempbyte2=byte;
    I2C_NAK();                          //NAK
    //I2C_restart();
    I2C_Stop_Bit();                     // Send Stop Bit

    uart_tx(tempbyte1);               //send data off raw by UART
    uart_tx(tempbyte2);
}


int main(void) {

    // set up oscillator control register, using internal OSC at 16MHz.
    OSCCONbits.IRCF = 0x07; //set OSCCON IRCF bits to select OSC frequency 16MHz
    OSCCONbits.SCS = 0x02; //set the SCS bits to select internal oscillator block
    //OSCTUNEbits.PLLEN = 0x01;   // PLL ENABLE FOSC -> 64MHz
    //OSCTUNEbits.TUN = 0x63;     ///trim up that frequency to get closed to 115200

    init_io();
    serial_init();
  
    SSPCON1bits.SSPM=0x08;       // I2C Master mode, clock = Fosc/(4 * (SSPADD+1))
    SSPCON1bits.SSPEN=1;         // enable MSSP port
    SSPADD = 0x09;             // 100KHz

    // ***********************************************************************************
    __delay_10ms(100);

    
    //init -- check and wait for IMU
    
    // test
    tempbyte1 = 0xFF;
    
    uart_tx(tempbyte1);               //send data off raw by UART
    uart_tx(0xAA);
    
    __delay_10ms(100);
    
    read_imu_status();    
    //set IMU for 9DOF
    __delay_10ms(10);
    
    
    write_imu_9DOF();
    
    //     UART method
    //     uart_tx(0xAA);                   //Start
    //     uart_tx(0x00);                   //read
    //     uart_tx(0x3D);                   //address 
    //     uart_tx(0x01);                   //length 
    //     uart_tx(0x1C);                   //data 9DOF

    __delay_10ms(50);

    while (1) {
         __delay_10ms(10);                   //delay for debugging

        LATAbits.LA0 = 0;           //good rx flag off
        //LATCbits.LATC3 = 0;
        //__delay_ms(149);
        //LATCbits.LATC3 = 1;     //debugging
        read_imu_cal_status();
  
        LATAbits.LA0 = 1;           //good rx flag on
         __delay_10ms(150);                   //delay for debugging
        
     }                                      //... wash, rinse, repeat
    return;
}



So yeah, again also sloppy but maybe you can use some of it. Price is right anyways.

Okay well maybe you might have notices a TINY gap in posting… it seems I greatly underestimated the amount of time a baby consumes in your life. I have a 9 month old son now.. he is running around trying to chew on USB cables (his favorite)… he’s just now realizing a bit of independence and with a recent purchase of a nice Lenovo Yoga 900 to replace my couple month old dead Sony Vaio I now can develop from the couch.. though I have a porta-crib in the workshop 🙂

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