Objective Development Forums 2011-02-26T09:41:49+02:00 https://forums.obdev.at/app.php/feed/topic/5476 2011-02-26T09:41:49+02:00 2011-02-26T09:41:49+02:00 https://forums.obdev.at/viewtopic.php?t=5476&p=17711#p17711 <![CDATA[Re: usbPoll() in Timer0 interrupt routine.]]> Statistics: Posted by Augend — Sat Feb 26, 2011 9:41 am

]]> 2011-02-25T03:57:47+02:00 2011-02-25T03:57:47+02:00 https://forums.obdev.at/viewtopic.php?t=5476&p=17699#p17699 <![CDATA[Re: usbPoll() in Timer0 interrupt routine.]]>
6.- Interrupts and Timing - Make sure that you're not using interrupts higher than the interrupt you have set for VUSB. Also make sure you're not disabling interrupts for longer than a few milliseconds, or that you have more than 10ms between calls to usbPoll(). A common mistake is to have sections of floating-point calculations in a main loop which does call usbPoll(), however, keep in mind that floating-point math is EXTREMELY slow, it may be worthwhile to place usbPoll() before and after these calculations.

Statistics: Posted by maxi — Fri Feb 25, 2011 3:57 am

]]> 2011-02-24T22:54:31+02:00 2011-02-24T22:54:31+02:00 https://forums.obdev.at/viewtopic.php?t=5476&p=17694#p17694 <![CDATA[usbPoll() in Timer0 interrupt routine.]]>
I wrote following program:

Code: 

#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>  /* for sei() */
#include <util/delay.h>     /* for _delay_ms() */
#include <avr/pgmspace.h>   /* required by usbdrv.h */
#include "usbdrv/usbdrv.h"
#include "usbdrv/requests.h"       /* The custom request numbers we use */
#include "usb_interface.h"
#include "lcd.h"

int main(void)
{
   DDRB = 0xFF;
   DDRD = 0xF0;         //D+ and D- both as input;
   
   // usb init      
    usbInit();
    usbDeviceDisconnect();  /* enforce re-enumeration, do this while interrupts are disabled! */
    usbDeviceConnect();
   // interrupt enable
    sei();      

   //Timer0 init
   TCCR0 = (1<<CS00);
   TIMSK =  (1<<TOIE0);
   TCNT0 = 223;   

   // init other devices
   lcd_init();   

   
    for(;;){}
    return 0;
}

/* ------------------------------------------------------------------------- */

ISR(TIMER0_OVF_vect)
{   
   usbPoll();
   TCNT0 = 230;
}


When I connect my device to my computer, the device is not recognized. There is something wrong with Timer0 interrupt routine. I do not even know if it is possible to place usbPoll() in interrupt routine. If I put usbPoll() to 'for' loop everything works fine. Could someone tell me if it is possible to call usbPoll() in any interrupt routine. If yes, please write how.

Statistics: Posted by maciek_nh — Thu Feb 24, 2011 10:54 pm

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