change keyboard report descriptor for NKRO.

It uses 1byte for modifiers and 15bytes(120bits) for keys now.

USB_NKRO.txt

@@ -1,6 +1,6 @@
 USB NKRO MEMO
 =============
-2010/12/07
+2010/12/09
 
 
 References
@@ -9,6 +9,9 @@ USB - boot mode, NKRO, compatibility, etc...
     http://geekhack.org/showthread.php?t=13162
 NKey Rollover - Overview, Testing Methodology, and Results
     http://geekhack.org/showwiki.php?title=NKey+Rollover+-+Overview+Testing+Methodology+and+Results
+dfj's NKRO(2010/06)
+    http://geekhack.org/showpost.php?p=191195&postcount=251
+    http://geekhack.org/showthread.php?p=204389#post204389
 
 
 Terminogy
@@ -22,18 +25,26 @@ membrane
 
 OS Support Status
 -----------------
-NKRO is possible at least relatively new OS.
+USB NKRO is possible *without* a custom driver.
-Following OS supports both Extended and Bitmarp report.
+At least following OSes supports.
     Windows7 64bit
+    WindowsXP
     Windows2000 SP4
     Ubuntu10.4(Linux 2.6)
+    MacOSX(To be tested)
+
+
+Custom Driver for USB NKRO
+--------------------------
+NOT NEEDED
+at least when using fllowing report formats on Windows, Linux or MacOSX.
 
 
 USB NKRO methods
 ----------------
 1. Virtual keyboards
     Keyboard can increase its KRO by using virtual keyboards with Standard or Extended report.
-    If the keyboard has 2 virtul keyboard with Standard report(6KRO), it gets 12KRO.
+    If the keyboard has 2 virtual keyboard with Standard report(6KRO), it gets 12KRO.
     Using this method means the keyboard is a composite device.
 
 2. Exteded report
@@ -70,28 +81,64 @@ Extended report is expected to be compatible with boot protocol.
 Bitmap report can send at most 128keys by 16bytes and 256keys by 32bytes.
 Bitmap report can achieve USB NKRO efficiently in terms of report size.
 Bitmap report needs a deliberation for boot protocol implementation.
+Bitmap report descriptor sample:
+        0x05, 0x01,                     // Usage Page (Generic Desktop),
+        0x09, 0x06,                     // Usage (Keyboard),
+        0xA1, 0x01,                     // Collection (Application),
+        // bitmap of modifiers
+        0x75, 0x01,                     //   Report Size (1),
+        0x95, 0x08,                     //   Report Count (8),
+        0x05, 0x07,                     //   Usage Page (Key Codes),
+        0x19, 0xE0,                     //   Usage Minimum (224),
+        0x29, 0xE7,                     //   Usage Maximum (231),
+        0x15, 0x00,                     //   Logical Minimum (0),
+        0x25, 0x01,                     //   Logical Maximum (1),
+        0x81, 0x02,                     //   Input (Data, Variable, Absolute), ;Modifier byte
+        // LED output report
+        0x95, 0x05,                     //   Report Count (5),
+        0x75, 0x01,                     //   Report Size (1),
+        0x05, 0x08,                     //   Usage Page (LEDs),
+        0x19, 0x01,                     //   Usage Minimum (1),
+        0x29, 0x05,                     //   Usage Maximum (5),
+        0x91, 0x02,                     //   Output (Data, Variable, Absolute),
+        0x95, 0x01,                     //   Report Count (1),
+        0x75, 0x03,                     //   Report Size (3),
+        0x91, 0x03,                     //   Output (Constant),
+        // bitmap of keys
+        0x95, (REPORT_BYTES-1)*8,	//   Report Count (),
+        0x75, 0x01,                     //   Report Size (1),
+        0x15, 0x00,                     //   Logical Minimum (0),
+        0x25, 0x01,                     //   Logical Maximum(1),
+        0x05, 0x07,                     //   Usage Page (Key Codes),
+        0x19, 0x00,                     //   Usage Minimum (0),
+        0x29, (REPORT_BYTES-1)*8-1,	//   Usage Maximum (),
+        0x81, 0x02,                     //   Input (Data, Variable, Absolute),
+        0xc0                            // End Collection
+where REPORT_BYTES is a report size in bytes.
 
 
-Compatibility Problem
+Considerations
----------------------
+--------------
+Compatibility
+    boot protocol
+    minor/old system
         Some BIOS doesn't send SET_PROTCOL request, a keyboard can't switch to boot protocol mode.
         This may cuase a problem on a keyboard which uses other report than Standard.
+Reactivity
+    USB polling time
+    OS/Driver processing time
 
 
 Windows Problem
 ---------------
 1. Windows accepts only 6keys  in case of Standard report.
         It should be able to send 6keys plus 8modifiers.
-
 2. Windows accepts only 10keys in case of 16bytes Extended report.
         It should be able to send 14keys plus 8modifiers.
-
 3. Windows accepts only 18keys in case of 32bytes Extended report.
         It should be able to send 30keys plus 8modifiers.
-
 If keys are pressed in excess of the number, wrong keys are registered on Windows.
 
-
 This problem will be reportedly fixed soon.(2010/12/05)
     http://forums.anandtech.com/showpost.php?p=30873364&postcount=17
 

usb.c

@@ -173,6 +173,7 @@ static uint8_t PROGMEM keyboard2_hid_report_desc[] = {
         0x05, 0x01,                     // Usage Page (Generic Desktop),
         0x09, 0x06,                     // Usage (Keyboard),
         0xA1, 0x01,                     // Collection (Application),
+        // bitmap of modifiers
         0x75, 0x01,                     //   Report Size (1),
         0x95, 0x08,                     //   Report Count (8),
         0x05, 0x07,                     //   Usage Page (Key Codes),
@@ -181,18 +182,17 @@ static uint8_t PROGMEM keyboard2_hid_report_desc[] = {
         0x15, 0x00,                     //   Logical Minimum (0),
         0x25, 0x01,                     //   Logical Maximum (1),
         0x81, 0x02,                     //   Input (Data, Variable, Absolute), ;Modifier byte
-        0x95, 0x01,          //   Report Count (1),
+        // LED output report
-        0x75, 0x08,          //   Report Size (8),
-        0x81, 0x03,          //   Input (Constant),                 ;Reserved byte
         0x95, 0x05,                     //   Report Count (5),
         0x75, 0x01,                     //   Report Size (1),
         0x05, 0x08,                     //   Usage Page (LEDs),
         0x19, 0x01,                     //   Usage Minimum (1),
         0x29, 0x05,                     //   Usage Maximum (5),
-        0x91, 0x02,          //   Output (Data, Variable, Absolute), ;LED report
+        0x91, 0x02,                     //   Output (Data, Variable, Absolute),
         0x95, 0x01,                     //   Report Count (1),
         0x75, 0x03,                     //   Report Size (3),
-        0x91, 0x03,          //   Output (Constant),                 ;LED report padding
+        0x91, 0x03,                     //   Output (Constant),
+        // bitmap of keys
         0x95, KBD2_REPORT_KEYS*8,       //   Report Count (),
         0x75, 0x01,                     //   Report Size (1),
         0x15, 0x00,                     //   Logical Minimum (0),

usb_keyboard.c

@@ -211,6 +211,7 @@ static inline int8_t _send_report(usb_keyboard_report_t *report, uint8_t endpoin
             UENUM = endpoint;
     }
     UEDATX = report->mods;
+    if (!usb_keyboard_nkro)
         UEDATX = 0;
     for (uint8_t i = keys_start; i < keys_end; i++) {
             UEDATX = report->keys[i];

usb_keyboard.h

@@ -18,7 +18,7 @@
 #define KBD2_ENDPOINT		5
 #define KBD2_SIZE		16
 #define KBD2_BUFFER		EP_DOUBLE_BUFFER
-#define KBD2_REPORT_KEYS	(KBD2_SIZE - 2)
+#define KBD2_REPORT_KEYS	(KBD2_SIZE - 1)
 #endif
 
 #if defined(KBD2_REPORT_KEYS) && KBD2_REPORT_KEYS > KBD_REPORT_KEYS