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+/*
+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)
+{
+ idle();
+ _delay_ms(1000);
+
+/* Not needed to initialize in fact.
+ uint8_t data;
+ 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) {
+ debug_hex(data); debug(" ");
+ }
+ 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 M0110 raw codes.
+ Scan codes are 1 byte size and MSB(bit7) is set when key is released.
+
+ scancode = ((raw&0x80) | ((raw&0x7F)>>1))
+
+ M0110 M0120
+ ,---------------------------------------------------------. ,---------------.
+ | `| 1| 2| 3| 4| 5| 6| 7| 8| 9| 0| -| =|Backs| |Clr| -|Lft|Rgt|
+ |---------------------------------------------------------| |---------------|
+ |Tab | Q| W| E| R| T| Y| U| I| O| P| [| ]| \| | 7| 8| 9|Up |
+ |---------------------------------------------------------| |---------------|
+ |CapsLo| A| S| D| F| G| H| J| K| L| ;| '|Return| | 4| 5| 6|Dn |
+ |---------------------------------------------------------| |---------------|
+ |Shift | Z| X| C| V| B| N| M| ,| ,| /| | | 1| 2| 3| |
+ `---------------------------------------------------------' |-----------|Ent|
+ |Opt|Mac | Space |Enter|Opt| | 0| .| |
+ `------------------------------------------------' `---------------'
+ ,---------------------------------------------------------. ,---------------.
+ | 32| 12| 13| 14| 15| 17| 16| 1A| 1C| 19| 1D| 1B| 18| 33| | 47| 4E| 46| 42|
+ |---------------------------------------------------------| |---------------|
+ | 30| 0C| 0D| 0E| 0F| 10| 11| 20| 22| 1F| 23| 21| 1E| 2A| | 59| 5B| 5C| 4D|
+ |---------------------------------------------------------| |---------------|
+ | 39| 00| 01| 02| 03| 05| 04| 26| 28| 25| 29| 27| 24| | 56| 57| 58| 48|
+ |---------------------------------------------------------| |---------------|
+ | 38| 06| 07| 08| 09| 0B| 2D| 2E| 2B| 2F| 2C| 38| | 53| 54| 55| |
+ `---------------------------------------------------------' |-----------| 4C|
+ | 3A| 37| 31 | 34| 3A| | 52| 41| |
+ `------------------------------------------------' `---------------'
+
+ International keyboard(See page 22 of "Technical Info for 128K/512K")
+ ,---------------------------------------------------------.
+ | 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| 0A| 38|
+ `---------------------------------------------------------'
+ | 3A| 37| 34 | 31| 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/
+M0110 raw 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
+*/