Output/pjrcUSB/arm/usb_keyboard.c

   1 #include "usb_dev.h"
   2 #include "usb_keyboard.h"
   3 #include <Lib/USBLib.h>
   4 #include <string.h> // for memcpy()
   5
   6
   7 // Maximum number of transmit packets to queue so we don't starve other endpoints for memory
   8 #define TX_PACKET_LIMIT 4
   9
  10 static uint8_t transmit_previous_timeout=0;
  11
  12 // When the PC isn't listening, how long do we wait before discarding data?
  13 #define TX_TIMEOUT_MSEC 50
  14
  15 #if F_CPU == 96000000
  16   #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 596)
  17 #elif F_CPU == 48000000
  18   #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 428)
  19 #elif F_CPU == 24000000
  20   #define TX_TIMEOUT (TX_TIMEOUT_MSEC * 262)
  21 #endif
  22
  23
  24 // send the contents of keyboard_keys and keyboard_modifier_keys
  25 uint8_t usb_keyboard_send(void)
  26 {
  27         uint32_t wait_count=0;
  28         usb_packet_t *tx_packet;
  29
  30         while (1) {
  31                 if (!usb_configuration) {
  32                         return -1;
  33                 }
  34                 if (usb_tx_packet_count(KEYBOARD_ENDPOINT) < TX_PACKET_LIMIT) {
  35                         tx_packet = usb_malloc();
  36                         if (tx_packet) break;
  37                 }
  38                 if (++wait_count > TX_TIMEOUT || transmit_previous_timeout) {
  39                         transmit_previous_timeout = 1;
  40                         return -1;
  41                 }
  42                 yield();
  43         }
  44         *(tx_packet->buf) = USBKeys_Modifiers;
  45         *(tx_packet->buf + 1) = 0;
  46         memcpy(tx_packet->buf + 2, USBKeys_Array, USB_MAX_KEY_SEND);
  47         tx_packet->len = 8;
  48         usb_tx(KEYBOARD_ENDPOINT, tx_packet);
  49
  50         return 0;
  51 }
  52