Merge branch 'm0110a'

1 files changed, 353 insertions, 135 deletions

diff --git a/m0110.c b/m0110.c
index 522c3ec0dc..a669c85a48 100644
--- a/m0110.c
+++ b/m0110.c
@@ -1,5 +1,5 @@
 /*
-Copyright 2011 Jun WAKO <wakojun@gmail.com>
+Copyright 2011,2012 Jun WAKO <wakojun@gmail.com>
 
 This software is licensed with a Modified BSD License.
 All of this is supposed to be Free Software, Open Source, DFSG-free,
@@ -34,6 +34,7 @@ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
 */
+/* M0110A Support was contributed by skagon@github */
 
 #include <stdbool.h>
 #include <avr/io.h>
@@ -43,6 +44,9 @@ POSSIBILITY OF SUCH DAMAGE.
 #include "debug.h"
 
 
+static inline uint8_t raw2scan(uint8_t raw);
+static inline uint8_t inquiry(void);
+static inline uint8_t instant(void);
 static inline void clock_lo(void);
 static inline void clock_hi(void);
 static inline bool clock_in(void);
@@ -57,130 +61,6 @@ static inline void idle(void);
 static inline void request(void);
 
 
-/*
-Primitive M0110 Library for AVR
-==============================
-
-
-Signaling
----------
-CLOCK is always from KEYBOARD. DATA are sent with MSB first.
-
-1) IDLE: both lines are high.
-    CLOCK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-    DATA  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-
-2) KEYBOARD->HOST: HOST reads bit on rising edge.
-    CLOCK ~~~~~~~~~~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~~~~~~~~~
-    DATA  ~~~~~~~~~~~~X777777X666666X555555X444444X333333X222222X111111X000000X~~~~~~~
-                      <--> 160us(clock low)
-                         <---> 180us(clock high)
-
-3) HOST->KEYBOARD: HOST asserts bit on falling edge.
-    CLOCK ~~~~~~~~~~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~~~~~~~~~
-    DATA  ~~~~~~|_____X777777X666666X555555X444444X333333X222222X111111X000000X~~~~~~~
-                <----> 840us(request to send by host)                     <---> 80us(hold DATA)
-                      <--> 180us(clock low)
-                         <---> 220us(clock high)
-
-
-Protocol
---------
-COMMAND:
-    Inquiry     0x10    get key event
-    Instant     0x12    get key event
-    Model       0x14    get model number(M0110 responds with 0x09)
-                        bit 7   1 if another device connected(used when keypad exists?)
-                        bit4-6  next device model number
-                        bit1-3  keyboard model number
-                        bit 0   always 1
-    Test        0x16    test(ACK:0x7D/NAK:0x77)
-
-KEY EVENT:
-    bit 7       key state(0:press 1:release)
-    bit 6-1     scan code(see below)
-    bit 0       always 1
-    To get scan code use this: ((bits&(1<<7)) | ((bits&0x7F))>>1).
-
-    Note: On the M0110A, the numpad keys and the arrow keys are preceded by 0x79.
-          Moreover, the numpad keys =, /, * and + are preceded by shift-down 0x71 on press and shift-up 0xF1 on release.
-          So, the data transferred by nupmad 5 is "79 2F" whereas for numpad + it's "71 79 0D".
-
-SCAN CODE:
-    m0111_recv_key() function returns follwing scan codes instead of raw key events.
-    Scan codes are 1 byte long and bit7 is set when key is released. 
-
-    M0110
-    ,---------------------------------------------------------.
-    |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|Backs|
-    |---------------------------------------------------------|
-    |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P|  [|  ]|  \|
-    |---------------------------------------------------------|
-    |CapsLo|  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '|Return|
-    |---------------------------------------------------------|
-    |Shift   |  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|        |
-    `---------------------------------------------------------'
-         |Opt|Mac |         Space               |Enter|Opt|
-         `------------------------------------------------'
-    ,---------------------------------------------------------.
-    | 32| 12| 13| 14| 15| 17| 16| 1A| 1C| 19| 1D| 1B| 18|   33|
-    |---------------------------------------------------------|
-    |   30| 0C| 0D| 0E| 0F| 10| 11| 20| 22| 1F| 23| 21| 1E| 2A|
-    |---------------------------------------------------------|
-    |    39| 00| 01| 02| 03| 05| 04| 26| 28| 25| 29| 27|    24|
-    |---------------------------------------------------------|
-    |      38| 06| 07| 08| 09| 0B| 2D| 2E| 2B| 2F| 2C|      38|
-    `---------------------------------------------------------'
-         | 3A|  37|             31              |   34| 3A|
-         `------------------------------------------------'
-
-    M0110A
-    ,---------------------------------------------------------. ,---------------.
-    |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|Bcksp| |Clr|  =|  /|  *|
-    |---------------------------------------------------------| |---------------|
-    |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P|  [|  ]|   | |  7|  8|  9|  -|
-    |-----------------------------------------------------'   | |---------------|
-    |CapsLo|  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '|Return| |  4|  5|  6|  +|
-    |---------------------------------------------------------| |---------------|
-    |Shift   |  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|Shft|Up | |  1|  2|  3|   |
-    |---------------------------------------------------------' |-----------|Ent|
-    |Optio|Mac    |           Space           |  \|Lft|Rgt|Dn | |      0|  .|   |
-    `---------------------------------------------------------' `---------------'
-    ,---------------------------------------------------------. ,---------------.
-    | 32| 12| 13| 14| 15| 17| 16| 1A| 1C| 19| 1D| 1B| 18|   33| | 47| 68| 6D| 62|
-    |---------------------------------------------------------| |---------------|
-    |   30| 0C| 0D| 0E| 0F| 10| 11| 20| 22| 1F| 23| 21| 1E|   | | 59| 5B| 5C| 4E|
-    |-----------------------------------------------------'   | |---------------|
-    |    39| 00| 01| 02| 03| 05| 04| 26| 28| 25| 29| 27|    24| | 56| 57| 58| 66|
-    |---------------------------------------------------------| |---------------|
-    |      38| 06| 07| 08| 09| 0B| 2D| 2E| 2B| 2F| 2C|  38| 4D| | 53| 54| 55|   |
-    |---------------------------------------------------------' |-----------| 4C|
-    |   3A|     37|            31             | 2A| 46| 42| 48| |     52| 41|   |
-    `---------------------------------------------------------' `---------------'
-
-
-References
-----------
-Technical Info for 128K/512K and Plus
-    ftp://ftp.apple.asimov.net/pub/apple_II/documentation/macintosh/Mac%20Hardware%20Info%20-%20Mac%20128K.pdf
-    ftp://ftp.apple.asimov.net/pub/apple_II/documentation/macintosh/Mac%20Hardware%20Info%20-%20Mac%20Plus.pdf
-Protocol:
-    Page 20 of Tech Info for 128K/512K
-    http://www.mac.linux-m68k.org/devel/plushw.php
-Connector:
-    Page 20 of Tech Info for 128K/512K
-    http://www.kbdbabel.org/conn/kbd_connector_macplus.png
-Signaling:
-    http://www.kbdbabel.org/signaling/kbd_signaling_mac.png
-    http://typematic.blog.shinobi.jp/Entry/14/
-Scan Codes:
-    Page 22 of Tech Info for 128K/512K
-    Page 07 of Tech Info for Plus
-    http://m0115.web.fc2.com/m0110.jpg
-    http://m0115.web.fc2.com/m0110a.jpg
-*/
-
-
 #define WAIT_US(stat, us, err) do { \
     if (!wait_##stat(us)) { \
         m0110_error = err; \
@@ -202,6 +82,9 @@ Scan Codes:
     } \
 } while (0)
 
+#define KEY(raw)        ((raw) & 0x7f)
+#define IS_BREAK(raw)   (((raw) & 0x80) == 0x80)
+
 
 uint8_t m0110_error = 0;
 
@@ -212,10 +95,6 @@ void m0110_init(void)
     idle();
     _delay_ms(1000);
 
-    // Model Number
-    // M0110 : 0x09  00001001 : model number 4 (100)
-    // M0110A: 0x0B  00001011 : model number 5 (101)
-    // M0110 & M0120: ???
     m0110_send(M0110_MODEL);
     data = m0110_recv();
     print("m0110_init model: "); phex(data); print("\n");
@@ -273,17 +152,179 @@ ERROR:
     return 0xFF;
 }
 
+/*
+Handling for exceptional case of key combinations for M0110A
+
+Shift and Calc/Arrow key could be operated simultaneously:
+
+    Case Shift   Arrow   Events          Interpret
+    -------------------------------------------------------------------
+    1    Down    Down    71, 79, DD      Calc(d)*a *b
+    2    Down    Up      71, 79, UU      Arrow&Calc(u)*a
+    3    Up      Down    F1, 79, DD      Shift(u) *c
+    4    Up      Up      F1, 79, UU      Shift(u) and Arrow&Calc(u)*a
+
+    Case Shift   Calc    Events          Interpret
+    -------------------------------------------------------------------
+    5(1) Down    Down    71, 71, 79, DD  Shift(d) and Cacl(d)
+    6(2) Down    Up      F1, 71, 79, UU  Shift(u) and Arrow&Calc(u)*a
+    7(1) Up      Down    F1, 71, 79, DD  Shift(u) and Calc(d)
+    8(4) Up      Up      F1, F1, 79, UU  Shift(ux2) and Arrow&Calc(u)*a
+
+During Calc key is hold:
+    Case Shift   Arrow   Events          Interpret
+    -------------------------------------------------------------------
+    A(3) ----    Down    F1, 79, DD      Shift(u) *c
+    B    ----    Up      79, UU          Arrow&Calc(u)*a
+    C    Down    ----    F1, 71          Shift(u) and Shift(d)
+    D    Up      ----    F1              Shift(u)
+    E    Hold    Down    79, DD          Normal
+    F    Hold    Up      79, UU          Arrow&Calc(u)*a
+    G(1) Down    Down    F1, 71, 79, DD  Shift(u)*b and Calc(d)*a
+    H(2) Down    Up      F1, 71, 79, UU  Shift(u) and Arrow&Calc(u)*a
+    I(3) Up      Down    F1, F1, 79, DD  Shift(ux2) *c
+    J(4) Up      Up      F1, 79, UU      Shift(u) and Arrow&Calc(u)*a
+
+    Case Shift   Calc    Events          Interpret
+    -------------------------------------------------------------------
+    K(1) ----    Down    71, 79, DD      Calc(d)*a
+    L(4) ----    Up      F1, 79, UU      Shift(u) and Arrow&Calc(u)*a
+    M(1) Hold    Down    71, 79, DD      Calc(d)*a
+    N    Hold    Up      79, UU          Arrow&Calc(u)*a
+
+    Where DD/UU indicates part of Keypad Down/Up event.
+    *a: Impossible to distinguish btween Arrow and Calc event.
+    *b: Shift(d) event is ignored.
+    *c: Arrow/Calc(d) event is ignored.
+*/
 uint8_t m0110_recv_key(void)
 {
-    uint8_t key;
+    static uint8_t keybuf = 0x00;
+    static uint8_t keybuf2 = 0x00;
+    static uint8_t rawbuf = 0x00;
+    uint8_t raw, raw2, raw3;
+
+    if (keybuf) {
+        raw = keybuf;
+        keybuf = 0x00;
+        return raw;
+    }
+    if (keybuf2) {
+        raw = keybuf2;
+        keybuf2 = 0x00;
+        return raw;
+    }
+
+    if (rawbuf) {
+        raw = rawbuf;
+        rawbuf = 0x00;
+    } else {
+        raw = instant();  // Use INSTANT for better response. Should be INQUIRY ?
+    }
+    switch (KEY(raw)) {
+        case M0110_KEYPAD:
+            raw2 = instant();
+            switch (KEY(raw2)) {
+                case M0110_ARROW_UP:
+                case M0110_ARROW_DOWN:
+                case M0110_ARROW_LEFT:
+                case M0110_ARROW_RIGHT:
+                    if (IS_BREAK(raw2)) {
+                        // Case B,F,N:
+                        keybuf = (raw2scan(raw2) | M0110_CALC_OFFSET); // Calc(u)
+                        return (raw2scan(raw2) | M0110_KEYPAD_OFFSET); // Arrow(u)
+                    }
+                    break;
+            }
+            // Keypad or Arrow
+            return (raw2scan(raw2) | M0110_KEYPAD_OFFSET);
+            break;
+        case M0110_SHIFT:
+            raw2 = instant();
+            switch (KEY(raw2)) {
+                case M0110_SHIFT:
+                    // Case: 5-8,C,G,H
+                    rawbuf = raw2;
+                    return raw2scan(raw); // Shift(d/u)
+                    break;
+                case M0110_KEYPAD:
+                    // Shift + Arrow, Calc, or etc.
+                    raw3 = instant();
+                    switch (KEY(raw3)) {
+                        case M0110_ARROW_UP:
+                        case M0110_ARROW_DOWN:
+                        case M0110_ARROW_LEFT:
+                        case M0110_ARROW_RIGHT:
+                            if (IS_BREAK(raw)) {
+                                if (IS_BREAK(raw3)) {
+                                    // Case 4:
+                                    print("(4)\n");
+                                    keybuf2 = raw2scan(raw); // Shift(u)
+                                    keybuf  = (raw2scan(raw3) | M0110_CALC_OFFSET); // Calc(u)
+                                    return (raw2scan(raw3) | M0110_KEYPAD_OFFSET);  // Arrow(u)
+                                } else {
+                                    // Case 3:
+                                    print("(3)\n");
+                                    return (raw2scan(raw)); // Shift(u)
+                                }
+                            } else {
+                                if (IS_BREAK(raw3)) {
+                                    // Case 2:
+                                    print("(2)\n");
+                                    keybuf  = (raw2scan(raw3) | M0110_CALC_OFFSET); // Calc(u)
+                                    return (raw2scan(raw3) | M0110_KEYPAD_OFFSET);  // Arrow(u)
+                                } else {
+                                    // Case 1:
+                                    print("(1)\n");
+                                    return (raw2scan(raw3) | M0110_CALC_OFFSET); // Calc(d)
+                                }
+                            }
+                            break;
+                        default:
+                            // Shift + Keypad
+                            keybuf = (raw2scan(raw3) | M0110_KEYPAD_OFFSET);
+                            return raw2scan(raw);   // Shift(d/u)
+                            break;
+                    }
+                    break;
+                default:
+                    // Shift + Normal keys
+                    keybuf = raw2scan(raw2);
+                    return raw2scan(raw);   // Shift(d/u)
+                    break;
+            }
+            break;
+        default:
+            // Normal keys
+            return raw2scan(raw);
+            break;
+    }
+}
+
+
+static inline uint8_t raw2scan(uint8_t raw) {
+    return (raw == M0110_NULL) ?  M0110_NULL : (
+                (raw == M0110_ERROR) ?  M0110_ERROR : (
+                    ((raw&0x80) | ((raw&0x7F)>>1))
+                )
+           );
+}
+
+static inline uint8_t inquiry(void)
+{
     m0110_send(M0110_INQUIRY);
-    key = m0110_recv();
-    if (key == 0xFF || key == M0110_NULL)
-        return M0110_NULL;
-    else 
-        return M0110_RAW2SCAN(key);
+    return m0110_recv();
 }
 
+static inline uint8_t instant(void)
+{
+    m0110_send(M0110_INSTANT);
+    uint8_t data = m0110_recv();
+    if (data != M0110_NULL) {
+        phex(data); print(" ");
+    }
+    return data;
+}
 
 static inline void clock_lo()
 {
@@ -354,3 +395,180 @@ static inline void request(void)
     clock_hi();
     data_lo();
 }
+
+
+
+/*
+Primitive M0110 Library for AVR
+==============================
+
+
+Signaling
+---------
+CLOCK is always from KEYBOARD. DATA are sent with MSB first.
+
+1) IDLE: both lines are high.
+    CLOCK ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+    DATA  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+2) KEYBOARD->HOST: HOST reads bit on rising edge.
+    CLOCK ~~~~~~~~~~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~~~~~~~~~
+    DATA  ~~~~~~~~~~~~X777777X666666X555555X444444X333333X222222X111111X000000X~~~~~~~
+                      <--> 160us(clock low)
+                         <---> 180us(clock high)
+
+3) HOST->KEYBOARD: HOST asserts bit on falling edge.
+    CLOCK ~~~~~~~~~~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~|__|~~~~~~~~~~~
+    DATA  ~~~~~~|_____X777777X666666X555555X444444X333333X222222X111111X000000X~~~~~~~
+                <----> 840us(request to send by host)                     <---> 80us(hold DATA)
+                      <--> 180us(clock low)
+                         <---> 220us(clock high)
+
+
+Protocol
+--------
+COMMAND:
+    Inquiry     0x10    get key event with block
+    Instant     0x12    get key event
+    Model       0x14    get model number(M0110 responds with 0x09)
+                        bit 7   1 if another device connected(used when keypad exists?)
+                        bit4-6  next device model number
+                        bit1-3  keyboard model number
+                        bit 0   always 1
+    Test        0x16    test(ACK:0x7D/NAK:0x77)
+
+KEY EVENT:
+    bit 7       key state(0:press 1:release)
+    bit 6-1     scan code(see below)
+    bit 0       always 1
+    To get scan code use this: ((bits&(1<<7)) | ((bits&0x7F))>>1).
+
+    Note: On the M0110A, Keypad keys and Arrow keys are preceded by 0x79.
+          Moreover, some Keypad keys(=, /, * and +) are preceded by 0x71 on press and 0xF1 on release.
+
+ARROW KEYS:
+    Arrow keys and Calc keys(+,*,/,= on keypad) share same byte sequence and preceding byte of
+    Calc keys(0x71 and 0xF1) means press and release event of SHIFT. This causes a very confusing situation,
+    it is difficult or impossible to tell Calc key from Arrow key plus SHIFT in some cases.
+
+    Raw key events:
+            press               release
+            ----------------    ----------------
+    Left:         0x79, 0x0D          0x79, 0x8D
+    Right:        0x79, 0x05          0x79, 0x85
+    Up:           0x79, 0x1B          0x79, 0x9B
+    Down:         0x79, 0x11          0x79, 0x91
+    Pad+:   0x71, 0x79, 0x0D    0xF1, 0x79, 0x8D
+    Pad*:   0x71, 0x79, 0x05    0xF1, 0x79, 0x85
+    Pad/:   0x71, 0x79, 0x1B    0xF1, 0x79, 0x9B
+    Pad=:   0x71, 0x79, 0x11    0xF1, 0x79, 0x91
+
+
+RAW CODE:
+    M0110A
+    ,---------------------------------------------------------. ,---------------.
+    |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|Bcksp| |Clr|  =|  /|  *|
+    |---------------------------------------------------------| |---------------|
+    |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P|  [|  ]|   | |  7|  8|  9|  -|
+    |-----------------------------------------------------'   | |---------------|
+    |CapsLo|  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '|Return| |  4|  5|  6|  +|
+    |---------------------------------------------------------| |---------------|
+    |Shift   |  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|Shft|Up | |  1|  2|  3|   |
+    |---------------------------------------------------------' |-----------|Ent|
+    |Optio|Mac    |           Space           |  \|Lft|Rgt|Dn | |      0|  .|   |
+    `---------------------------------------------------------' `---------------'
+    ,---------------------------------------------------------. ,---------------.
+    | 65| 25| 27| 29| 2B| 2F| 2D| 35| 39| 33| 3B| 37| 31|   67| |+0F|*11|*1B|*05|
+    |---------------------------------------------------------| |---------------|
+    |   61| 19| 1B| 1D| 1F| 23| 21| 41| 45| 3F| 47| 43| 3D|   | |+33|+37|+39|+1D|
+    |-----------------------------------------------------'   | |---------------|
+    |    73| 01| 03| 05| 07| 0B| 09| 4D| 51| 4B| 53| 4F|    49| |+2D|+2F|+31|*0D|
+    |---------------------------------------------------------| |---------------|
+    |      71| 0D| 0F| 11| 13| 17| 5B| 5D| 27| 5F| 59|  71|+1B| |+27|+29|+2B|   |
+    |---------------------------------------------------------' |-----------|+19|
+    |   75|     6F|            63             | 55|+0D|+05|+11| |    +25|+03|   |
+    `---------------------------------------------------------' `---------------'
+    + 0x79, 0xDD / 0xF1, 0xUU
+    * 0x71, 0x79,DD / 0xF1, 0x79, 0xUU
+
+
+MODEL NUMBER:
+    M0110:           0x09  00001001 : model number 4 (100)
+    M0110A:          0x0B  00001011 : model number 5 (101)
+    M0110 & M0120:   ???
+
+
+Scan Code
+---------
+    m0110_recv_key() function returns following scan codes instead of raw key events.
+    Scan codes are 1 byte long and MSB(bit7) is set when key is released. 
+
+    M0110
+    ,---------------------------------------------------------.
+    |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|Backs|
+    |---------------------------------------------------------|
+    |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P|  [|  ]|  \|
+    |---------------------------------------------------------|
+    |CapsLo|  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '|Return|
+    |---------------------------------------------------------|
+    |Shift   |  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|        |
+    `---------------------------------------------------------'
+         |Opt|Mac |         Space               |Enter|Opt|
+         `------------------------------------------------'
+    ,---------------------------------------------------------.
+    | 32| 12| 13| 14| 15| 17| 16| 1A| 1C| 19| 1D| 1B| 18|   33|
+    |---------------------------------------------------------|
+    |   30| 0C| 0D| 0E| 0F| 10| 11| 20| 22| 1F| 23| 21| 1E| 2A|
+    |---------------------------------------------------------|
+    |    39| 00| 01| 02| 03| 05| 04| 26| 28| 25| 29| 27|    24|
+    |---------------------------------------------------------|
+    |      38| 06| 07| 08| 09| 0B| 2D| 2E| 2B| 2F| 2C|      38|
+    `---------------------------------------------------------'
+         | 3A|  37|             31              |   34| 3A|
+         `------------------------------------------------'
+
+    M0110A
+    ,---------------------------------------------------------. ,---------------.
+    |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|Bcksp| |Clr|  =|  /|  *|
+    |---------------------------------------------------------| |---------------|
+    |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P|  [|  ]|   | |  7|  8|  9|  -|
+    |-----------------------------------------------------'   | |---------------|
+    |CapsLo|  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '|Return| |  4|  5|  6|  +|
+    |---------------------------------------------------------| |---------------|
+    |Shift   |  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|Shft|Up | |  1|  2|  3|   |
+    |---------------------------------------------------------' |-----------|Ent|
+    |Optio|Mac    |           Space           |  \|Lft|Rgt|Dn | |      0|  .|   |
+    `---------------------------------------------------------' `---------------'
+    ,---------------------------------------------------------. ,---------------.
+    | 32| 12| 13| 14| 15| 17| 16| 1A| 1C| 19| 1D| 1B| 18|   33| | 47| 68| 6D| 62|
+    |---------------------------------------------------------| |---------------|
+    |   30| 0C| 0D| 0E| 0F| 10| 11| 20| 22| 1F| 23| 21| 1E|   | | 59| 5B| 5C| 4E|
+    |-----------------------------------------------------'   | |---------------|
+    |    39| 00| 01| 02| 03| 05| 04| 26| 28| 25| 29| 27|    24| | 56| 57| 58| 66|
+    |---------------------------------------------------------| |---------------|
+    |      38| 06| 07| 08| 09| 0B| 2D| 2E| 2B| 2F| 2C|  38| 4D| | 53| 54| 55|   |
+    |---------------------------------------------------------' |-----------| 4C|
+    |   3A|     37|            31             | 2A| 46| 42| 48| |     52| 41|   |
+    `---------------------------------------------------------' `---------------'
+
+
+References
+----------
+Technical Info for 128K/512K and Plus
+    ftp://ftp.apple.asimov.net/pub/apple_II/documentation/macintosh/Mac%20Hardware%20Info%20-%20Mac%20128K.pdf
+    ftp://ftp.apple.asimov.net/pub/apple_II/documentation/macintosh/Mac%20Hardware%20Info%20-%20Mac%20Plus.pdf
+Protocol:
+    Page 20 of Tech Info for 128K/512K
+    http://www.mac.linux-m68k.org/devel/plushw.php
+Connector:
+    Page 20 of Tech Info for 128K/512K
+    http://www.kbdbabel.org/conn/kbd_connector_macplus.png
+Signaling:
+    http://www.kbdbabel.org/signaling/kbd_signaling_mac.png
+    http://typematic.blog.shinobi.jp/Entry/14/
+Scan Codes:
+    Page 22 of Tech Info for 128K/512K
+    Page 07 of Tech Info for Plus
+    http://m0115.web.fc2.com/m0110.jpg
+    http://m0115.web.fc2.com/m0110a.jpg
+*/