1 files changed, 574 insertions, 0 deletions

diff --git a/protocol/m0110.c b/protocol/m0110.c
new file mode 100644
index 000000000..a669c85a4
--- /dev/null
+++ b/protocol/m0110.c
@@ -0,0 +1,574 @@
+/*
+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,
+GPL-compatible, and OK to use in both free and proprietary applications.
+Additions and corrections to this file are welcome.
+
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in
+  the documentation and/or other materials provided with the
+  distribution.
+
+* Neither the name of the copyright holders nor the names of
+  contributors may be used to endorse or promote products derived
+  from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+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>
+#include <avr/interrupt.h>
+#include <util/delay.h>
+#include "m0110.h"
+#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);
+static inline void data_lo(void);
+static inline void data_hi(void);
+static inline bool data_in(void);
+static inline uint16_t wait_clock_lo(uint16_t us);
+static inline uint16_t wait_clock_hi(uint16_t us);
+static inline uint16_t wait_data_lo(uint16_t us);
+static inline uint16_t wait_data_hi(uint16_t us);
+static inline void idle(void);
+static inline void request(void);
+
+
+#define WAIT_US(stat, us, err) do { \
+    if (!wait_##stat(us)) { \
+        m0110_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+#define WAIT_MS(stat, ms, err) do { \
+    uint16_t _ms = ms; \
+    while (_ms) { \
+        if (wait_##stat(1000)) { \
+            break; \
+        } \
+        _ms--; \
+    } \
+    if (_ms == 0) { \
+        m0110_error = err; \
+        goto ERROR; \
+    } \
+} while (0)
+
+#define KEY(raw)        ((raw) & 0x7f)
+#define IS_BREAK(raw)   (((raw) & 0x80) == 0x80)
+
+
+uint8_t m0110_error = 0;
+
+
+void m0110_init(void)
+{
+    uint8_t data;
+    idle();
+    _delay_ms(1000);
+
+    m0110_send(M0110_MODEL);
+    data = m0110_recv();
+    print("m0110_init model: "); phex(data); print("\n");
+
+    m0110_send(M0110_TEST);
+    data = m0110_recv();
+    print("m0110_init test: "); phex(data); print("\n");
+}
+
+uint8_t m0110_send(uint8_t data)
+{
+    m0110_error = 0;
+
+    request();
+    WAIT_MS(clock_lo, 250, 1);  // keyboard may block long time
+    for (uint8_t bit = 0x80; bit; bit >>= 1) {
+        WAIT_US(clock_lo, 250, 3);
+        if (data&bit) {
+            data_hi();
+        } else {
+            data_lo();
+        }
+        WAIT_US(clock_hi, 200, 4);
+    }
+    _delay_us(100); // hold last bit for 80us
+    idle();
+    return 1;
+ERROR:
+    print("m0110_send err: "); phex(m0110_error); print("\n");
+    _delay_ms(500);
+    idle();
+    return 0;
+}
+
+uint8_t m0110_recv(void)
+{
+    uint8_t data = 0;
+    m0110_error = 0;
+
+    WAIT_MS(clock_lo, 250, 1);  // keyboard may block long time
+    for (uint8_t i = 0; i < 8; i++) {
+        data <<= 1;
+        WAIT_US(clock_lo, 200, 2);
+        WAIT_US(clock_hi, 200, 3);
+        if (data_in()) {
+            data |= 1;
+        }
+    }
+    idle();
+    return data;
+ERROR:
+    print("m0110_recv err: "); phex(m0110_error); print("\n");
+    _delay_ms(500);
+    idle();
+    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)
+{
+    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);
+    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()
+{
+    M0110_CLOCK_PORT &= ~(1<<M0110_CLOCK_BIT);
+    M0110_CLOCK_DDR  |=  (1<<M0110_CLOCK_BIT);
+}
+static inline void clock_hi()
+{
+    /* input with pull up */
+    M0110_CLOCK_DDR  &= ~(1<<M0110_CLOCK_BIT);
+    M0110_CLOCK_PORT |=  (1<<M0110_CLOCK_BIT);
+}
+static inline bool clock_in()
+{
+    M0110_CLOCK_DDR  &= ~(1<<M0110_CLOCK_BIT);
+    M0110_CLOCK_PORT |=  (1<<M0110_CLOCK_BIT);
+    _delay_us(1);
+    return M0110_CLOCK_PIN&(1<<M0110_CLOCK_BIT);
+}
+static inline void data_lo()
+{
+    M0110_DATA_PORT &= ~(1<<M0110_DATA_BIT);
+    M0110_DATA_DDR  |=  (1<<M0110_DATA_BIT);
+}
+static inline void data_hi()
+{
+    /* input with pull up */
+    M0110_DATA_DDR  &= ~(1<<M0110_DATA_BIT);
+    M0110_DATA_PORT |=  (1<<M0110_DATA_BIT);
+}
+static inline bool data_in()
+{
+    M0110_DATA_DDR  &= ~(1<<M0110_DATA_BIT);
+    M0110_DATA_PORT |=  (1<<M0110_DATA_BIT);
+    _delay_us(1);
+    return M0110_DATA_PIN&(1<<M0110_DATA_BIT);
+}
+
+static inline uint16_t wait_clock_lo(uint16_t us)
+{
+    while (clock_in()  && us) { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_clock_hi(uint16_t us)
+{
+    while (!clock_in() && us) { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_lo(uint16_t us)
+{
+    while (data_in() && us)  { asm(""); _delay_us(1); us--; }
+    return us;
+}
+static inline uint16_t wait_data_hi(uint16_t us)
+{
+    while (!data_in() && us)  { asm(""); _delay_us(1); us--; }
+    return us;
+}
+
+static inline void idle(void)
+{
+    clock_hi();
+    data_hi();
+}
+
+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
+*/