usb_keyboard.c

   1 #include <avr/interrupt.h>
   2 #include <avr/pgmspace.h>
   3 #include "usb_keyboard.h"
   4
   5
   6 // which modifier keys are currently pressed
   7 // 1=left ctrl,    2=left shift,   4=left alt,    8=left gui
   8 // 16=right ctrl, 32=right shift, 64=right alt, 128=right gui
   9 uint8_t keyboard_modifier_keys=0;
  10
  11 // which keys are currently pressed, up to 6 keys may be down at once
  12 uint8_t keyboard_keys[6]={0,0,0,0,0,0};
  13
  14 // protocol setting from the host.  We use exactly the same report
  15 // either way, so this variable only stores the setting since we
  16 // are required to be able to report which setting is in use.
  17 uint8_t keyboard_protocol=1;
  18
  19 // the idle configuration, how often we send the report to the
  20 // host (ms * 4) even when it hasn't changed
  21 uint8_t keyboard_idle_config=125;
  22
  23 // count until idle timeout
  24 uint8_t keyboard_idle_count=0;
  25
  26 // 1=num lock, 2=caps lock, 4=scroll lock, 8=compose, 16=kana
  27 volatile uint8_t keyboard_leds=0;
  28
  29
  30 // perform a single keystroke
  31 int8_t usb_keyboard_press(uint8_t key, uint8_t modifier)
  32 {
  33         int8_t r;
  34
  35         keyboard_modifier_keys = modifier;
  36         keyboard_keys[0] = key;
  37         r = usb_keyboard_send();
  38         if (r) return r;
  39         keyboard_modifier_keys = 0;
  40         keyboard_keys[0] = 0;
  41         return usb_keyboard_send();
  42 }
  43
  44 // send the contents of keyboard_keys and keyboard_modifier_keys
  45 int8_t usb_keyboard_send(void)
  46 {
  47         uint8_t i, intr_state, timeout;
  48
  49         if (!usb_configured()) return -1;
  50         intr_state = SREG;
  51         cli();
  52         UENUM = KEYBOARD_ENDPOINT;
  53         timeout = UDFNUML + 50;
  54         while (1) {
  55                 // are we ready to transmit?
  56                 if (UEINTX & (1<<RWAL)) break;
  57                 SREG = intr_state;
  58                 // has the USB gone offline?
  59                 if (!usb_configured()) return -1;
  60                 // have we waited too long?
  61                 if (UDFNUML == timeout) return -1;
  62                 // get ready to try checking again
  63                 intr_state = SREG;
  64                 cli();
  65                 UENUM = KEYBOARD_ENDPOINT;
  66         }
  67         UEDATX = keyboard_modifier_keys;
  68         UEDATX = 0;
  69         for (i=0; i<6; i++) {
  70                 UEDATX = keyboard_keys[i];
  71         }
  72         UEINTX = 0x3A;
  73         keyboard_idle_count = 0;
  74         SREG = intr_state;
  75         return 0;
  76 }