From c to pbp

[savnik]

How to change this code to picbasic pro.Also i want to use xtal 4MHZ

#include <16f84a.h>
#fuses HS,NOWDT,PROTECT,PUT
#use delay(clock=20000000) //one instruction=0.2us
//////////////////////////// HS1YWN /////////////////////////////////

void main()
{
 int ltime;
 SET_TRIS_B(0x00);
  for (ltime=0;ltime<50;ltime++)
  {
    output_high(PIN_B7);
    delay_ms(50);
    output_low(PIN_B7);
    delay_ms(50);
  }

  while (TRUE)
  {
    output_b(0x01);
    delay_cycles(59);
    output_b(0x02);
    delay_cycles(59);
    output_b(0x41);
    delay_cycles(59);
    output_b(0x42);
    delay_cycles(59);
  }
}
/////////////////////// the end !! ////////////////////////////////////////

[Jerson]

Here you go, 'unverified' code.

@ device PIC16f84, HS, NOWDT, PROTECT, PUT

ltime  var  word
PIN_B7 var PORTB.7

   TRISB = 0
   for ltime = 0 to 50
      PIN_B7 = 1
      pause 50
      PIN_B7 = 0
      pause 50
   next

   while (1)
      PORTB = 1
      pause_us(59)
      PORTB = 2
      pause_us(59)
      PORTB = $41
      pause_us(59)
      PORTB = $42
      pause_us(59)
   wend
/////////////////////// the end !! ////////////////////////////////////////

[T.Jackson]

That was very nice of you, Jerson, to take the time to do that. I think I agree with your conversion - while I have no prior knowledge of C, I'm studying Java at the moment and starting to many similarities between them.

[savnik]

Here you go, 'unverified' code.

@ device PIC16f84, HS, NOWDT, PROTECT, PUT

ltime  var  word
PIN_B7 var PORTB.7

   TRISB = 0
   for ltime = 0 to 50
      PIN_B7 = 1
      pause 50
      PIN_B7 = 0
      pause 50
   next

   while (1)
      PORTB = 1
      pause_us(59)
      PORTB = 2
      pause_us(59)
      PORTB = $41
      pause_us(59)
      PORTB = $42
      pause_us(59)
   wend
/////////////////////// the end !! ////////////////////////////////////////

Thank you.I will try.

[Bruce]

If you're going to convert this to produce the same timing at 4MHz, you'll
need to use an assembler delay routine.

At 20MHz, like the original C version, delay_cycles(59); gives you a delay of
59 * 200nS instruction cycles. 59 * 200nS = 11.8uS.

PAUSEUS at 4MHz is limited to a minimum delay period of 24uS, and with an
instruction time of 1uS at 4MHz, you're still going to be off by a minimum of
200nS.

12uS is about as close as you can get to the original 11.8uS delay period.

'  For 4MHz use XT_OSC
   @ DEVICE PIC16F84A, XT_OSC,WDT_OFF,PROTECT_OFF,PWRT_ON

   DEFINE OSC 4
   ltime VAR BYTE

   GOTO Main
   
PAUSE12:  ' CALL to here = 2uS  
ASM
    GOTO $+1 ; 2uS
    GOTO $+1 ; 2uS
    GOTO $+1 ; 2uS
    GOTO $+1 ; 2uS
    RETURN   ; 2uS (12uS total delay time)
ENDASM

Main:
   TRISB = 0
   FOR ltime = 0 TO 49 ' 50 loops total
    PORTB.7 = 1
    PAUSE 50
    PORTB.7 = 0
    PAUSE 50
   NEXT ltime

   WHILE (1)
    PORTB = 1
    CALL PAUSE12
    PORTB = 2
    CALL PAUSE12
    PORTB = $41
    CALL PAUSE12
    PORTB = $42
    CALL PAUSE12
   WEND

   END

This would give you very close to the same program & timing. The difference
is the delay between port updates in the WHILE loop are 12uS VS 11.8uS.

[savnik]

Thank you.
I want to test this code with Attached Image.
At port.0 and port.1 must have 38khz and at port.6 must have 19khz

[keithdoxey]

Thank you.
I want to test this code with Attached Image.
At port.0 and port.1 must have 38khz and at port.6 must have 19khz

You may get the code to work but I dont see how that schematic is going to work if you are trying to build a stereo encoder for an FM transmitter.

Both audio inputs are labelled as {RIGHT} sorry...R IN L IN {end of edit} instead of right and left and the circuit appears to just chop both inputs up at a rate of 38kHz. Presumably the PIC is outputing the two 38kHz signals out of phase otherwise you may as well use the same signal !!!

FM broadcasts were designed to be Mono compatable so have a mono audio signal (L+R) with a difference signal (L-R) carried on a 38kHz subcarrier.

The 19kHz carrier is to operate the pilot indicator in the receiver and switch on the demux to regenerate the original Left and Right signals from Mono + Side.

http://www.irational.org/sic/radio/tech.html#Stereo

gives a block schematic of a stereo encoder which is totally different from what your schematic seems to do.