f_14_4_audio.c

PIC_Hi-Tech_C_Mike_Pearces_I2C_routines Microchi PIC_Hi-Tech C_I2C_for_EEPROM_24LC01B Code

#include "config.h"
#include "serial.c"
#include "serio.c"
#include "i2cmsu.c"
#include "i2c_memutil.c"

// Audio lab
// want to sample at roughly 8 Khz rate, or 125 us

volatile unsigned char bufptr, interrupt_flag;
volatile unsigned char buf_flag;
volatile unsigned char record_mode, playback_mode;
volatile unsigned char buf_1[64], buf_2[64];

#if defined(HI_TECH_C)
void interrupt timer_isr(void)
#endif
#if defined(__18CXX)
#pragma interrupt timer_isr
void timer_isr(void)
#endif
{

  if (TMR2IF) {
    //clear timer interrupt flag
	TMR2IF=0;     
    if (record_mode) {
      //read A/D register, save in buffer 
      if (!buf_flag) buf_2[bufptr] = ADRESH;
      else buf_1[bufptr] = ADRESH;
      GODONE = 1; // start new conversion
      bufptr++;
      if (bufptr == 64) {
	    bufptr = 0;
	    interrupt_flag = 1;
        // toggler buffer flag
	    buf_flag = ~buf_flag; 
      }
    }
    if (playback_mode) {
      interrupt_flag = 1;
    }
  }
}

#define EEPROM 0xA0     // I2C EEPROM, write lower blk
#define EEPROMR 0xA1    // I2C EEPROM, read lower blk
#define EEPROMW_HB 0xA8 // I2C EEPROM, write upper blk
#define EEPROMR_HB 0xA9 // I2C EEPROM, read upper blk
#define DAC 0x58        // I2C DAC 01011000 

unsigned int addr;
char i, inchar, adc_value;

void do_playback(void) {
  // playback approach -- start read of ADC at location zero.
  playback_mode = 1;
  RB4 = 1;  // set switch for playback
  pcrlf (); printf("Doing Playback"); pcrlf ();

    // this is important, there are TWO internal address counters
    // both have to be initialized to zero 
    // clear lower block address counter
  i2c_start();
  i2c_put(EEPROM);  // send write cmd to set low block address counter
  i2c_put(0); // send high address byte
  i2c_put(0); // send low address byte
  i2c_stop(); // send stop

  // clear upper block address counter
  i2c_start();
  i2c_put(EEPROMW_HB); //block select = 1
  i2c_put(0); // send high address byte
  i2c_put(0); // send low address byte
  i2c_stop(); // send stop

  addr = 0;
  // initialize DAC to output zero
  i2c_start(); i2c_put(DAC); i2c_put(0x00); i2c_put(0x00); i2c_stop();

    // enable interrupts 
  IPEN = 0; TMR2IF = 0; TMR2IE = 1; PEIE = 1;   GIE = 1;  
  // start timer 2 
  TMR2ON = 1 ;
  interrupt_flag = 0;  //clear semaphore
  do {
    i2c_start();
    // read byte
    if (addr & 0x8000) i2c_put(EEPROMR_HB);
    else i2c_put(EEPROMR);  
    inchar=i2c_get(1);   //NAK
    i2c_stop();
    // if int flag is set, we not keeping up with sample rate!!!
    if (interrupt_flag) putch('!');
    // wait for interrupt
    while (!interrupt_flag);  
    interrupt_flag = 0;
    i2c_start();   // send to DAC
    i2c_put(DAC);
    i2c_put(0x00);
    i2c_put(inchar);
    i2c_stop();
    addr = addr+1;
    CLRWDT();   //asm("clrwdt")
  }while(1);
}

void do_record(void){
  addr = 0; buf_flag = 0;
  pcrlf (); printf("Capturing 64K of audio from ADC"); 
  pcrlf ();
  record_mode = 1; // 
  GODONE = 1; // start new converstion
  // enable TMR2 interrupt
  TMR2IF = 0; TMR2IE = 1; 
  IPEN = 0; PEIE = 1;  GIE = 1;  
  TMR2ON = 1; // start timer 2 //
  interrupt_flag = 0;
  do {
    if (interrupt_flag) putch('!');
    while (!interrupt_flag) {
      CLRWDT();              // asm("clrwdt"); 
    };  // wait for block write
    // do block write //
    interrupt_flag = 0;
    if  (buf_flag) 	
      i2c_memwrite(EEPROM,addr,(unsigned char *)buf_2);
    else 
      i2c_memwrite(EEPROM,addr,(unsigned char *)buf_1);
    addr = addr + 64;
    putch('*');
  }while(addr);  // becomes zero on wraparound
  printf("64K Capture complete. ");
  printf("Press reset to continue.");
  pcrlf ();
}

void main(void){
  TRISB4 = 0; // RB4 is output
  RB4 = 0;   // initially low for record
  // configure A/D 
  ADCON0 = 0x80;  // sampling freq = Fsoc/32, channel 0 
  ADCON1 = 0x0E;  ADON = 1;  // Port A analog input, right justification of result 
  // set baud rate //
  serial_init(95,1); // 19200 in HSPLL mode, crystal = 7.3728 MHz 
  if (!TO || !RI) {
    if (!RI) {RI = 1;printf("Software reset has occurred, press reset\n");}
    else { // disable watchdog timer, print msg
      SWDTEN = 0;printf("Watchdog timer reset has occurred, press reset.\n");
    }
    pcrlf();
    if (i2c_errstat) i2c_print_err();
    SLEEP();          //asm("sleep"); 
  }
  bufptr=0;buf_flag = 0;
  record_mode = 0;
  playback_mode = 0;
  SWDTEN = 1;  // enable watchdog timer
  // enable I2C //
  //  i2c_init(17); // about 400Khz  for HSPLL mode, crystal = 7.3728 MHz 
  i2c_init(12); // lowest value that works, works with slow playback

  // configure timer 2
  // post scale of 1, prescale of 16, PR2 =76
  TOUTPS3 = 0; TOUTPS2 = 0; TOUTPS1 = 0;  TOUTPS0 = 0;
  T2CKPS1 = 1; // pre scale of 16 
#if defined(HI_TECH_C) 
  PR2 = 76;    // 6 Khz //
#endif
#if defined(__18CXX) 
  PR2 = 114;    // 4 Khz, MCC18 is a somewhat slower //
#endif

  pcrlf ();printf("Enter 'r'(record), 'p'(playback), 'c'(calibrate), 'e'(examine): ");
  inchar=getch();
  if (inchar == 'c') {
    while(1) {
      GODONE = 1;
      while (GODONE);  // wait for end of conversion 
      adc_value = ADRESH;  // upper 8-bits
      printf("%x",adc_value);
      pcrlf();
    }
  }

  if (inchar == 'e') {
    addr = 0;
    while(1) {
      i2c_memread(EEPROM,addr,(unsigned char *)buf_1); // do read
      for(i = 0;i< 64;i++) printf("%x ",buf_1[i]);
      pcrlf();
      printf("Any key continues read...");pcrlf();
      getch();
      addr = addr+64;
    }
  }
  if (inchar == 'r') do_record();
  if (inchar == 'p') do_playback();

  SWDTEN = 0;  // disable watchdog timer
  SLEEP();     // asm("sleep")
}// end main

//for MCC18, place the interrupt vector goto
#if defined(__18CXX)
#if defined(HIGH_INTERRUPT)
#pragma code HighVector=HIGH_INTERRUPT
#else
#pragma code HighVector=0x0008  
#endif
void HighVector (void)
{
    _asm goto timer_isr _endasm
}
#pragma code
#endif