• (1) Sending data using pulse width modulation
• (2) Sending data using FSK modulation

(1) Sending data using pulse width modulation

Assume the component name "CM1". Properties setting:

The typical usage of this component shows sending a byte of data by means of PWM modulation. Logic 1 is send by 10 ms mark and 20 ms space. Logic 0 is send by 10 ms mark and 10 ms space.

MAIN.C

volatile byte OnEnd;                 /* The OnEnd event flag */

void SendBytePWM(byte Data)          /* Sends a byte by PWM modulated signal */
{
  byte i;

  OnEnd=0;
  if(Data & 0x01) {
    (void)CM1_SetSpaceWidthMode(1);  /* LSB=1 */
  }
  else {
    (void)CM1_SetSpaceWidthMode(0);  /* LSB=0 */
  }
  (void)CM1_Enable();                /* Enable the signal output */
  for(i=7;i!=0;i--){                 /* Send the rest of the byte - 7 bits */
    Data = Data >> 1;                /* Right shift the data */
    while(!OnEnd) ;                  /* Wait for end of modulation cycle */
    OnEnd = 0;                       /* Clear the event flag */
    if(Data & 0x01) {
      (void)CM1_SetSpaceWidthMode(1);  /* bit=1 */
    }
    else {
      (void)CM1_SetSpaceWidthMode(0);  /* bit=0 */
    }
  }
  while(!OnEnd) ;                     /* Wait for end of modulation cycle */
  (void)CM1_Disable();                /* Disable the signal output */
}

void main(void)
{
.
.
  SendBytePWM(0xa9);                  /* Send 0xa9 as a data */
.
.
}

EVENTS.C

extern volatile byte OnEnd;

void CM1_OnEnd(void)
{
  OnEnd++;
}

(2) Sending data using FSK modulation

Interrupt Service/event: Enabled, Mode: FSK, Primary carrier frequency settings: F1 = 2 kHz, primary carrier high pulse width and low pulse width = 250 us, Secondary carrier frequency settings: F2 = 4 kHz, secondary carrier high pulse width and low pulse width = 125 us, Mark pulse width in carrier clocks: 5, Modulation space: Disabled, Methods enabled: Enable, Disable, SwapCarrierFreq.

The typical usage of this component shows sending a byte of data by means of FSK modulation. Each bit is modulated by two carrier frequencies. Logic 0 by F1 followed with F2 and logic 1 by F2 followed with F1.

MAIN.C

volatile byte OnEnd;               /* The OnEnd event flag */

void SendByteFSK(byte Data)        /* Sends a byte by FSK modulated signal */
{
  byte i;
  byte Last;

  Last = 0;
  if(Data & 0x01) {
    (void)CM1_SwapCarrierFreq();     /* LSB=1 */
    Last ^= 1;                       /* store last transmitted byte*/
  }
  (void)CM1_Enable();                /* Enable the signal output */
  OnEnd = 0;
  for(i=7;i!=0;i--){                 /* Send the rest of the byte - 7 bits */
    Data = Data >> 1;                /* Right shift the data */
    while(OnEnd != 2) ;               /* Wait for two modulation cycles */
    OnEnd = 0;                       /* Clear the event flag */
    if((Data & 0x01)!=Last) {
      (void)CM1_SwapCarrierFreq();   /* Bit is different from last one sent */
      Last ^= 1;                     /* Store last transmitted byte*/
    }
  }
  while(OnEnd != 1) ;                 /* Wait for one modulation cycle */
  (void)CM1_Disable();               /* Disable the signal output */
}

void main(void)
{
.
.
  SendByteFSK(0xa9);                 /* Send 0xa9 as a data */
.
.
}

EVENTS.C

extern volatile byte OnEnd;

void CM1_OnEnd(void)
{
  OnEnd++;
}