RF modules using mikrobasic and PIC mcu's

[ktone11]

I'm trying to program transmitter and receiver to transmit a temperature reading on an LCD.
The PIC transmitter seems to be working ok on proteus simulation, but receiving nothing on the receiver using a single wire using tx and rx UART.
Here is my code:

TRANSMITTER:

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Code Basic4GL - [expand]
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program tx
 
Dim i1, j1, j2, CS as byte
 
Dim Text as string[20]
Dim Deg as string[3]
Dim HalfDeg as byte
 
' This subroutine calculates one byte Checksum
Sub function CheckSum(dim byref cadena as string[20])as byte
 
    Dim i2 as byte
    Dim j3 as word
    j3 = 0
    For i2 = 0 to StrLen(cadena)-1
    j3 = j3 + cadena[i2]
    next i2
    result = Lo(j3)  ' Truncate Checksum to one byte
 
End sub
Main:
     ADCON0.0=0        ' Shut-off ADC module
     ADCON1=%00000110  ' PORTA pins digital
     PORTA = 255       ' PORTA high
     TRISA = 255       ' PORTA is input
 
     UART1_Init(19200) ' Initialize at 19200 Baud (the default baud rate for RF module)
 
while true             ' Endless loop.
 
     for i1 = 0 to 19  ' Initialize string Text
     Text[i1] = Chr(0)
     next i1
 
     ' One Wire operation
 
     Ow_Reset(PORTA,0) ' Reset One Wire
     ' (pin 2 (RA0/AN0) of PIC 16F876 connected with pin2 of DS1820)
 
     OW_Write(PORTA, 0, $CC) ' Send command to DS1820 (SKIP ROM)
     OW_Write(PORTA, 0, $44) ' Send command to DS1820 (INIT CONVERSION)
     Delay_us(120)
     Ow_Reset(PORTA,0)       ' Reset
     OW_Write(PORTA, 0, $CC) ' Send command to DS1820 (SKIP ROM)
     OW_Write(PORTA, 0, $BE) ' Send command to DS1820 (READ SCRATCHPAD)
 
     j1 = OW_Read(PORTA, 0)  ' Get the result (temperature Low byte)
     j2 = OW_Read(PORTA, 0)  ' Get the result (temperature High byte)
 
     if j2>0
     then
     j1 = -j1
     Text[0] = 45 ' ASCII code for "-" (minus sign)
     else         ' j1 = j1
     Text[0] = 43 ' ASCII code for "+" (plus sign)
     end if
     ByteToStr((j1 div 2), Deg)
 
     If j1 mod 2 = 0 then
     HalfDeg = 48 ' ASCII code for number "0"
     else
     HalfDeg = 53 ' ASCII code for number "5"
     end if
     ' Prepare the string to be transmitted:
 
     Text[1] = Deg[0]    ' Add temperature
     Text[2] = Deg[1]
     Text[3] = Deg[2]
     Text[4] = "."       ' Add decimal point
     Text[5] = HalfDeg   ' Add half degree = 5 or 0
 
     CS = CheckSum(Text) ' Calculate Checksum of string data
     Text[6] = CS        ' Add Checksum to string Text
     Text[7] = "O"       ' Add delimiter OK
     Text[8] = "K"
     UART1_Write_Text(Text)  ' Send string Text via USART and RF
     Delay_ms(2000)
wend
End.

---

RECEIVER:

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Code Basic4GL - [expand]
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program uart
 
dim LCD_RS as sbit at RB4_bit
    LCD_EN as sbit at RB5_bit
    LCD_D4 as sbit at RB0_bit
    LCD_D5 as sbit at RB1_bit
    LCD_D6 as sbit at RB2_bit
    LCD_D7 as sbit at RB3_bit
 
    LCD_RS_Direction as sbit at TRISB4_bit
    LCD_EN_Direction as sbit at TRISB5_bit
    LCD_D4_Direction as sbit at TRISB0_bit
    LCD_D5_Direction as sbit at TRISB1_bit
    LCD_D6_Direction as sbit at TRISB2_bit
    LCD_D7_Direction as sbit at TRISB3_bit
 
Dim LenText, CSreceived, CScalculated as byte
Dim Text as String[20]
Dim i as byte
' This subroutine calculates one byte Checksum
Sub function CheckSum(dim byref text2 as string[20])as byte
 
    Dim i2 as byte
    Dim j as word
    j = 0
    For i2 = 0 to StrLen(text2)-1
    j = j + text2[i2]
    next i2
    result = Lo(j)  'Checksum truncated to one byte
 
End sub
 
Main:
     Ansel=0           'Digital
     AnselH=0          'Digital
     ADCON0=0          'Turns off ADC
 
     UART1_Init(19200) ' Initialize to 19200 Bd (the default baud rate for RF module)
 
     Lcd_Init() ' Lcd Init for EasyPic5
 
     LCD_Cmd(_LCD_CLEAR)
     LCD_Cmd(_Lcd_Return_Home)
     LCD_Cmd(_LCD_CURSOR_OFF)
 
     Delay_ms(200)
 
while TRUE              ' Endless loop
 
     for i = 0 to 19    ' Initialize string Text
     Text[i] = Chr(0)
     next i
     while UART1_Data_Ready() = 0 NOP wend ' If there is no data, wait
 
     UART1_Read_Text(Text,"OK", 10)   ' Read received data via RF and USART
     ' until OK is received
     Delay_ms(200)
 
     LenText = StrLen(Text)
 
     CSreceived = Text[LenText-1] ' Read received Checksum
     Text[LenText-1] = Chr(0)     ' Remove Checksum of the string Text
 
     CScalculated = CheckSum(Text)' Calculate Checksum of received data
 
   If CSreceived = CScalculated   ' If the received Checksum and the
   ' calculated Checksum matches, then...
 
   then
     Lcd_Out(1, 1, "Temperature:")
     Lcd_Out(2, 1, Text)          ' Display temperature
     Lcd_Chr(2, 9, 223)           ' Display "º"
     Lcd_Chr(2, 10, "C")          ' Display "C"
 
   else  '  If the received Checksum and the calculated Checksum
   ' doesn't match, the data will be discarded
 
     Lcd_Out(1, 1, "Temperature:")
   end if
     Delay_ms(1000)
     LCD_Cmd(_LCD_CLEAR)  ' Clear LCD
     Lcd_Out(1, 1, "Temperature:")
 
wend
End.

---

 

[91divine]

Everything seems right in your code.
Some time ago i also made the same project using same method, but i wrote different code. I used PIC18F248

Here is the code i used.

Reciever

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Code C - [expand]
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#include <p18cxxx.h>
# pragma config OSC = HS, OSCS = OFF
# pragma config WDT = OFF
# pragma config BORV = 45, PWRT = ON, BOR = ON
# pragma config DEBUG = OFF, LVP = OFF, STVR = OFF
 
unsigned int i=0;
#define RS PORTBbits.RB2
#define E PORTBbits.RB3
 
//delay
void del(unsigned long int);
 
//serial functions
void serial_init(int); //initialising serial port at 19200 baudrate
char recchar();  //recieving character
 
//LCD functions
void lcd_init(); //initialising LCD 16x2 at 4bit mode
void lcmd(unsigned char); //sending command
void ldata(unsigned char); //printing character
 
//MAIN
void main(void)
{
char c; 
lcd_init();
 serial_init(16);
 
 while(1)
 {
   c=recchar();
   ldata(c);
 }
} 
 
void del(unsigned long int k)
{
 for(i=0;i<=k*10;i++);
}
void serial_init(int i) 
{
 TXSTA=0x24;
 if(i==16)
  SPBRG=51;
 else if(i==4)
  SPBRG=12;
 RCSTA=0x90;
}
char recchar() 
{
    while(PIR1bits.RCIF==0);
    return RCREG;
}
 
void lcd_init()
{
 TRISB=0x00;
 lcmd(0x33);
 lcmd(0x32);
 lcmd(0x28); 
 lcmd(0x0E); 
 lcmd(0x01); 
 lcmd(0x06); 
 lcmd(0x80); 
}
void lcmd(unsigned char cmd)
{
 PORTBbits.RB2=0;del(2);
 PORTB = (PORTB & 0x0F)|(cmd & 0xF0);del(2) ;
 PORTBbits.RB3=1;del(2);PORTBbits.RB3=0;del(2);
 PORTB = (PORTB & 0x0F)|(cmd <<4); del(2);
 PORTBbits.RB3=1;del(2);PORTBbits.RB3=0;del(2);
 del(10);
 }
void ldata(unsigned char data)
{
 PORTBbits.RB2=1;del(2);
 PORTB = (PORTB & 0x0F)|(data & 0xF0); del(2);
 PORTBbits.RB3=1;del(2);PORTBbits.RB3=0; del(2);
 PORTB = (PORTB & 0x0F)|(data <<4);del(2);
 PORTBbits.RB3=1;del(2);PORTBbits.RB3=0; del(2);
 del(10);
}
 
void lnum(int q)
{
 char a[10]; 
 int j;
 if(q<0)
  {
   ldata('-');
   q=q*(-1);
  }
 if(q==0)
  ldata('0');
 else
 {
  for(i=0;q>0;++i)
   {
     a[i]=q%10+48;
     q=q/10;
   }
  for(j=i-1;j>=0;--j)
     ldata(a[j]);
 }
}
void lstr(char *s)
{
 while(*s)
  {
   ldata(*s);
   s++;
  }
}

---

Transmitter

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Code C - [expand]
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void adc_init()
{
 TRISA=0xFF;
 ADCON0=0b00000001;
 ADCON1=0b10000010;
}
int adcread()
{ int i;
 while(1)
  {
   del(1);
   ADCON0bits.GO=1;
   while(ADCON0bits.GO!=0);
   i=(ADRESH*255)+ADRESL;
   return i;
  }
}
void main(void)
{
 T1CON = 0b00000001;
 adc_init();
 serial_init();
 char c;int i;
 while(1)
 { 
   i=adcread();
   lnum(i);
   sendnum(i);
   del_sec(1);
 } 
}

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Use the same function definitions for both the codes. They communicate at baud rate of 19200 and work at 16Mhz osc.

 

[ktone11]

Hi 91divine, thanks for your reply. I just wanted to know what compiler you used with the code. I tried it with Mikroc and it doesn't work

 

[91divine]

I used MPLab with Hi-Tech C compiler for this code