usb_extra.c

   1 #include <avr/interrupt.h>
   2 #include "usb_extra.h"
   3
   4 int8_t usb_extra_send(uint8_t bits)
   5 {
   6         uint8_t intr_state, timeout;
   7
   8         if (!usb_configured()) return -1;
   9         intr_state = SREG;
  10         cli();
  11         UENUM = EXTRA_ENDPOINT;
  12         timeout = UDFNUML + 50;
  13         while (1) {
  14                 // are we ready to transmit?
  15                 if (UEINTX & (1<<RWAL)) break;
  16                 SREG = intr_state;
  17                 // has the USB gone offline?
  18                 if (!usb_configured()) return -1;
  19                 // have we waited too long?
  20                 if (UDFNUML == timeout) return -1;
  21                 // get ready to try checking again
  22                 intr_state = SREG;
  23                 cli();
  24                 UENUM = EXTRA_ENDPOINT;
  25         }
  26
  27         UEDATX = 1; // report id
  28         UEDATX = bits;
  29
  30         UEINTX = 0x3A;
  31         SREG = intr_state;
  32         return 0;
  33 }