On Tue, 30 Jun 2015 09:49:50 -0500, ishka wrote:

> Hi,
> I am trying to interface RFID(RFid click which uses CR95HF 13.56 MHz
> contactless transceiver as well as trace antenna) with PIC18F8722. It
> used SPI communication.
> I am trying to get its eco-response but there is no output! I checked
> using oscilloscope the spi_write operation which is perfectly fine but i
> guess the problems is in read operation. i am attaching my code. Any
> help would be appreciated.  I am using MPLAB X v3.0 with C8 compiler
> v1.34.
> 
> 
> #include <p18f8722.h>
> #include <stdio.h>
> #include <stdlib.h>
> #include <spi.h>
> #include <xc.h>
> #include <delays.h>
> #include "display_LCD.h"
> 
> // CR95HF Commands Definition #define    ECHO                   0x55
> 
> #define SSI_1 PORTFbits.RF7 // RA2 #define SSI_0 PORTDbits.RD7 // RE1
> #define IRQ_IN PORTCbits.RC0 #define CS_rfid PORTEbits.RE0
> 
> void main() {
>     
>   MCU_Init();                           // Initialize MCU and
>   peripherals
>   
>   EchoResponse();
>   
> }
> 
> void MCU_Init(){
> 
>   // Configure RFid Click pins
>    ADCON1 = 0b1111; // set all bits of port a as digital
>   TRISEbits.RE0= 0;
>   TRISCbits.RC0=0;
>   TRISDbits.RD7=0;
>   TRISFbits.RF7=0;
>   
>   OpenSPI2(SPI_FOSC_64, MODE_10, SMPEND);   // Initialize SPI module
>   IRQ_IN=0;
>   CS_rfid = 0;
>   // Set in SPI mode SSI_1=0;
>   SSI_0=1;
> 
> 
> }
> 
> 
> char EchoResponse() {
>   CS = 0;
>     WriteSPI2(0x00);  // Send cmd to CR95HF WriteSPI2(ECHO);
>   CS = 1;
>   while(1){
>     CS = 0;
>       WriteSPI2(0x03);
>       tmp = ReadSPI2;
>     CS = 1;
>     display_LCD_l(tmp);
>      
>     if((res & 0x08) >> 3){
>       CS = 0; WriteSPI2(0x02);
>       tmp = ReadSPI2; CS = 1;
>       if(tmp == ECHO){
>         return 1;
>       }
>       return 0;
>     }
>   }
> }
> 
> 
> ---------------------------------------
> Posted through http://www.EmbeddedRelated.com

I suspect that ReadSPI2 is a function, and that your compiler is glossing 
over the fact that

  tmp = ReadSPI2;

puts the address of the function into tmp, rather than executing the 
function and putting its result into tmp.  A good compiler would be 
emitting warnings right and left over this.

I'm also pretty sure that you'll need to supply an address to ReadSPI2.

-- 
www.wescottdesign.com

Hi,
I am trying to interface RFID(RFid click which uses CR95HF 13.56 MHz
contactless transceiver as well as trace antenna) with PIC18F8722. It used
SPI communication.
I am trying to get its eco-response but there is no output! I checked
using oscilloscope the spi_write operation which is perfectly fine but i
guess the problems is in read operation. i am attaching my code. Any help
would be appreciated.  I am using MPLAB X v3.0 with C8 compiler v1.34. 


#include <p18f8722.h>
#include <stdio.h>
#include <stdlib.h>
#include <spi.h>
#include <xc.h>
#include <delays.h> 
#include "display_LCD.h" 

// CR95HF Commands Definition
#define    ECHO                   0x55

#define SSI_1 PORTFbits.RF7 // RA2
#define SSI_0 PORTDbits.RD7 // RE1
#define IRQ_IN PORTCbits.RC0
#define CS_rfid PORTEbits.RE0

void main() {
    
  MCU_Init();                           // Initialize MCU and peripherals
  
  EchoResponse();
  
}

void MCU_Init(){

  // Configure RFid Click pins
   ADCON1 = 0b1111; // set all bits of port a as digital
  TRISEbits.RE0= 0;
  TRISCbits.RC0=0;
  TRISDbits.RD7=0;
  TRISFbits.RF7=0;
  
  OpenSPI2(SPI_FOSC_64, MODE_10, SMPEND);   // Initialize SPI module
  IRQ_IN=0; 
  CS_rfid = 0;
  // Set in SPI mode 
  SSI_1=0;
  SSI_0=1;

  
}


char EchoResponse() {
  CS = 0;
    WriteSPI2(0x00);  // Send cmd to CR95HF
    WriteSPI2(ECHO);
  CS = 1;
  while(1){
    CS = 0;
      WriteSPI2(0x03);
      tmp = ReadSPI2;
    CS = 1;
    display_LCD_l(tmp);
     
    if((res & 0x08) >> 3){
      CS = 0;
      WriteSPI2(0x02);
      tmp = ReadSPI2;
      CS = 1;
      if(tmp == ECHO){
        return 1;
      }
      return 0;
    }
  }
}


---------------------------------------
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