4 files changed, 18 insertions, 20 deletions
diff --git a/converter/ibm4704_usb/README.md b/converter/ibm4704_usb/README.md
index 25b72ba671..15c826ab8b 100644
--- a/converter/ibm4704_usb/README.md
+++ b/converter/ibm4704_usb/README.md
@@ -8,6 +8,7 @@ Keyboard initialization process takes a few seconds at start up. During that you
 Update
 ------
 2015/05/05  Added keymaps for 107-key, 77-key and 50-key. Thanks, orihalcon @ geekhack!
+2015/05/19  Fixed a protocol handling bug.
 
 
 
diff --git a/converter/ibm4704_usb/config.h b/converter/ibm4704_usb/config.h
index d9d8d39bc0..2fee10fd61 100644
--- a/converter/ibm4704_usb/config.h
+++ b/converter/ibm4704_usb/config.h
@@ -53,7 +53,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 /* Pin interrupt on rising edge of clock */
 #define IBM4704_INT_INIT()  do { EICRA |= ((1<<ISC11)|(1<<ISC10)); } while (0)
-#define IBM4704_INT_ON()    do { EIMSK |=  (1<<INT1); } while (0)
+#define IBM4704_INT_ON()    do { EIFR |= (1<<INTF1); EIMSK |= (1<<INT1); } while (0)
 #define IBM4704_INT_OFF()   do { EIMSK &= ~(1<<INT1); } while (0)
 #define IBM4704_INT_VECT    INT1_vect
 
diff --git a/converter/ibm4704_usb/ibm4704.txt b/converter/ibm4704_usb/ibm4704.txt
index 50d8c98b08..e2d42f08fd 100644
--- a/converter/ibm4704_usb/ibm4704.txt
+++ b/converter/ibm4704_usb/ibm4704.txt
@@ -166,13 +166,14 @@ Data sent from host:
          |   `-----`--- scan code
          `------------- enable bit(0: enable repeat, 1: enable break)
 
-    00-77   Enable repeat(78-7F: invalid scancode)
-    80-F7   Enable break(F8-FF: invalid scancode)
+    00-79   Enable repeat
+    80-F9   Enable break(FA-FF are used as other commands, see above.)
     FE      Resend(011ah) no need to use
     FF      End(0114h) exits FC command mode.
 
 Response from keyboard:
     FD      Out of bound - Invalid scancode
+    --      OK - No response means that command is accepted.
 
 Examples:
     To enable break code of all keys.
diff --git a/converter/ibm4704_usb/matrix.c b/converter/ibm4704_usb/matrix.c
index 5f928d716f..155df9c38f 100644
--- a/converter/ibm4704_usb/matrix.c
+++ b/converter/ibm4704_usb/matrix.c
@@ -67,35 +67,31 @@ uint8_t matrix_cols(void)
 
 static void enable_break(void)
 {
-    uint8_t ret;
     print("Enable break: ");
     // valid scancode: 00-79h
     for (uint8_t code = 0; code < 0x7A; code++) {
-        while (ibm4704_send(0x80|code)) _delay_ms(1);
-        // get none when ok, get FD when out of bound
-        _delay_ms(5);
-        if ((ret = ibm4704_recv()) != 0xff) {
-            xprintf("c%02X:r%02X ", code, ret);
-        }
-        _delay_ms(1);
+        while (ibm4704_send(0x80|code)) _delay_ms(10);
+        _delay_ms(5);   // wait for response
+        // No response(FF) when ok, FD when out of bound
+        xprintf("s%02X:r%02X ", code, ibm4704_recv());
     }
-    _delay_us(1000);
-    while (ibm4704_send(0xFF)) { _delay_ms(1); } // End
+    while (ibm4704_send(0xFF)) { _delay_ms(10); } // End
     print("End\n");
 }
 
-void matrix_init(void)
-{
-    debug_enable = true;
 
+void matrix_setup(void)
+{
     ibm4704_init();
-    matrix_clear();
+}
 
-    _delay_ms(2000);    // wait for starting up debug console
+void matrix_init(void)
+{
+    debug_enable = true;
 
     print("IBM 4704 converter\n");
-    while (ibm4704_send(0xFE)) _delay_ms(1);    // resend
-    _delay_ms(5);
+    matrix_clear();
+    _delay_ms(2000);    // wait for keyboard starting up
     xprintf("Keyboard ID: %02X\n", ibm4704_recv());
     enable_break();
 }