12 bit ADC over USB at 10 kHz

[itisme]

Hello,

I'm trying sample one channel ADC at 10kHz and transmit the data over USB serial. The code (CCS C) is below.

Unfortunately USB halt after transmitting several tens of samples. I think the problem with the speed of "printf(usb_cdc_putc,...)", but have no idea how to solve it.

I'll appreciate for help.

#include <18F2553.h> 
#device ADC = 12 
//configure a 20MHz crystal to operate at 48MHz 
#fuses HSPLL,NOWDT,NOPROTECT,NOLVP,NODEBUG,USBDIV,PLL5,CPUDIV1,VREGEN 
#use delay(clock=48000000) 
//#use rs232(baud = 115200, xmit = PIN_C6, rcv = PIN_C7) 

#include <usb_cdc.h> 
//#include <input.c> 
//#include <stdlib.h> 

unsigned int16 adc_data; 
int32 i=0; 
int8 s2r=1; //s2r - Seconds to record 
int32 c2t; //c2r - Cycles to transmit 

//Initializing the RTOS Program 

#use rtos(timer = 0, minor_cycle = 10us) 

#task(rate = 100us, max = 10us) // 100uS -> 10kHz 
void transmit_over_usb() 
{ 
        //adc_data = read_adc(); 
        printf(usb_cdc_putc, "%Lu\n\r", read_adc()); 
        if(++i==10000)//(i == c2t) 
            rtos_terminate( ); 
} 

void main() 
{ 
   #use standard_io(A) 
    
   setup_adc_ports(ALL_ANALOG); 
   setup_adc(ADC_CLOCK_DIV_64); // for 48MHz OSC 
   //setup_adc(ADC_CLOCK_DIV_16); // For 20 MHz OSC 
   set_adc_channel(0); 
   delay_us(10); 
    
   usb_cdc_init(); 
   usb_init(); 

   while(!usb_cdc_connected()) {} 

   do 
   { 
      usb_task(); 
      if (usb_enumerated()) 
      { 
         wait_usb: // Label 
         while (usb_cdc_getc() != 'r') ; 
         i=0; 
         s2r=1; 
          
         c2t = (s2r*1e6)/250; // How many cycles to transmit the data. NOTE: Denumerator should be equal to "rate" in main RTOS task 
         output_high(PIN_B0); 
          
         rtos_run(); 

         output_low(PIN_B0); 
         // printf("Done!\n\r"); 
         printf(usb_cdc_putc,"5002\n\r"); 
         goto wait_usb; 
      } 
   } while (TRUE); 
}

 

[manoj madhavan]

hi itisme.....
I dont know to write a smplie line of code

can you help me to write a programme?
Please check my new thread...........please