Merge blargg's fix into adb.c

- <http://geekhack.org/index.php?topic=14290.msg1075201#msg1075201>

converter/adb_usb/led.c

@@ -15,12 +15,15 @@ You should have received a copy of the GNU General Public License
 along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-#include "stdint.h"
+#include <stdint.h>
+#include <util/delay.h>
 #include "adb.h"
 #include "led.h"
 
 
 void led_set(uint8_t usb_led)
 {
+    // need a wait to send command without miss
+    _delay_ms(100);
     adb_host_kbd_led(~usb_led);
 }

converter/adb_usb/matrix.c

@@ -67,6 +67,13 @@ uint8_t matrix_cols(void)
 void matrix_init(void)
 {
     adb_host_init();
+    // wait for keyboard to boot up and receive command
+    _delay_ms(1000);
+    // Enable keyboard left/right modifier distinction
+    // Addr:Keyboard(0010), Cmd:Listen(10), Register3(11)
+    // upper byte: reserved bits 0000, device address 0010
+    // lower byte: device handler 00000011
+    adb_host_listen(0x2B,0x02,0x03);
 
     // initialize matrix state: all keys off
     for (uint8_t i=0; i < MATRIX_ROWS; i++) matrix[i] = 0x00;