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PIC18f4550 and USB interrupt

 
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Grkan13



Joined: 06 Apr 2011
Posts: 14

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PIC18f4550 and USB interrupt
PostPosted: Mon Apr 30, 2012 1:10 pm     Reply with quote

Hello,

I'm trying to control a level mechanism via USB and buttons. My system is working great with buttons. There are 10 buttons to go each level. And I want to control the system from computer too.

When you press a button, its firing an interrupt from B port. I want to use USB interrupt on same way. Is it possible?

My interrupt code for buttons is at below

Code:

#int_RB
void RB_isr()
{
disable_interrupts(INT_RB);

delay_ms(10);

 if(input_State(pin_b4)==0)
      {
      go=1;
      button_pressed=1;
      set_adc_channel(0);
      delay_ms(50);
      level_adc = read_adc();
         if(level_adc<=50)
         {
            button_10_pressed=1;
            level=10;
         }
         else if(level_adc<=200)
         {
            button_9_pressed=1;
            level=9;
         }
         else if(level_adc<=300)
         {
            button_8_pressed=1;
            level=8;
         }
         else if(level_adc<=400)
         {
            button_7_pressed=1;
            level=7;
         }
         else if(level_adc<=500)
         {
            button_6_pressed=1;
            level=6;
         }
         else if(level_adc<=600)
         {
            button_5_pressed=1;
            level=5;;
          }
          else if(level_adc<=700)
          {
            button_4_pressed=1;
            level=4;
          }
          else if(level_adc<=800)
          {
            button_3_pressed=1;
            level=3;
           }
          else if(level_adc<=900)
            {
             button_2_pressed=1;
             level=2;
            }
          else if(level_adc<=1200)
            {
             button_1_pressed=1;
             level=1;
            }
      }
     enable_interrupts(INT_RB);
}


so what i want is, when i get the data from usb, an interrupt should be fired.

now i'm using below driver files.
Code:

#include <pic18_usb.h>
#include <USB_configuration.h>       
#include <usb.c>


It's my 1st USB try. I'm not so sure about these driver files. I've found these ones from one of the open-source project. Do I have to use all of these ones?

When I've checked those driver files. pic18_usb.h has those lines:

Code:
#int_usb
void usb_isr() {
   if (usb_state==USB_STATE_DETACHED) return;   //should never happen, though
   if (UIR) {
      debug_usb(debug_putc,"\r\n\n[%X] ",UIR);
      if (UIR_ACTV && UIE_ACTV) {usb_isr_activity();}  //activity detected.  (only enable after sleep)

      if (UCON_SUSPND) return;

      if (UIR_UERR && UIE_UERR) {usb_isr_uerr();}          //error has been detected

      if (UIR_URST && UIE_URST) {usb_isr_rst();}        //usb reset has been detected

      if (UIR_IDLE && UIE_IDLE) {usb_isr_uidle();}        //idle time, we can go to sleep
      if (UIR_SOF && UIE_SOF) {usb_isr_sof();}
      if (UIR_STALL && UIE_STALL) {usb_isr_stall();}        //a stall handshake was sent

      if (UIR_TRN && UIE_TRN) {
         usb_isr_tok_dne();
         UIR_TRN=0;    // clear the token done interrupt., 0x190.3
      }    //a token has been detected (majority of isrs)
   }
}


If I add the int_USB to the my main file. does it make any problem?

Thank you.
Ttelmah



Joined: 11 Mar 2010
Posts: 19539

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PostPosted: Mon Apr 30, 2012 2:08 pm     Reply with quote

You are looking the wrong way at this.

USB, is transferring 'data' all the time when a device is connected. There are configuration packets, polling packets, etc. etc.. You cannot use the USB interrupt to find out if data you want has arrived.

You need to _poll_ for data being available, and let the usb code handle the interrupts for you. Simplest to just use the usb_cdc drivers, and just call usb_kbhit, which will return 'true' when data has arrived.

Also, your serial code is foul. First, there is no point in disabling the INT_RB in the interrupt handler, and second you are delaying in an interrupt, which potentially means missing characters. If you did this in anything associated with USB, you _would_ lose connection.

Best Wishes
Grkan13



Joined: 06 Apr 2011
Posts: 14

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PostPosted: Wed May 02, 2012 8:33 am     Reply with quote

Thank you Ttelmah, I understand what you mean about USB, now I'm checking it whenever I need but I have a problem at one section.

Code:

 while(input_state(s7)==1)
                        {
                           output_high(level5);
                           delay_ms(200);
                           output_low(level5);
                           delay_ms(200);
                           if(button_pressed==1)
                           {
                              adc_button();
                              output_low(level5);
                              optic_middle();
                                 if(button_5_pressed==1)
                                 {
                                    optic_up();
                                    go=0;
                                    goto end;
                                 }
                                 else
                                    goto start;
                           }
                           if (usb_kbhit(1))
                           {
                              usb_get_packet(1, received_packet, 4);
                              if(received_packet[1]==0b00100000)
                              {
                                 optic_up();
                                 go=0;
                                 goto end;
                              }
                           }
                        }


At above part, software is waiting for 3 response; sensor, button or usb. and while waiting it needs to blink LED. When I try to get data from USB, its not working. But when I spam the button from PC or when I remove the blinking delays, its working fine. How can i solve this?

By the way thanks for INT_RB warnings. I've removed the a-d conversion out of interrupt, So there is no delay inside of isr now.
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