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+/*
+Copyright 2011 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.
+*/
+
+#include <stdbool.h>
+#include <util/delay.h>
+#include <avr/io.h>
+#include "adb.h"
+
+
+static inline void data_lo(void);
+static inline void data_hi(void);
+static inline bool data_in(void);
+#ifdef ADB_PSW_BIT
+static inline void psw_lo(void);
+static inline void psw_hi(void);
+static inline bool psw_in(void);
+#endif
+
+static inline void attention(void);
+static inline void place_bit0(void);
+static inline void place_bit1(void);
+static inline void send_byte(uint8_t data);
+static inline bool read_bit(void);
+static inline uint8_t read_byte(void);
+static inline uint8_t wait_data_lo(uint8_t us);
+static inline uint8_t wait_data_hi(uint8_t us);
+
+
+void adb_host_init(void)
+{
+ data_hi();
+#ifdef ADB_PSW_BIT
+ psw_hi();
+#endif
+}
+
+#ifdef ADB_PSW_BIT
+bool adb_host_psw(void)
+{
+ return psw_in();
+}
+#endif
+
+uint16_t adb_host_kbd_recv(void)
+{
+ uint16_t data = 0;
+ attention();
+ send_byte(0x2C); // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
+ place_bit0(); // Stopbit(0)
+ if (!wait_data_lo(0xFF)) // Tlt/Stop to Start(140-260us)
+ return 0; // No data to send
+ if (!read_bit()) // Startbit(1)
+ return -2;
+ data = read_byte();
+ data = (data<<8) | read_byte();
+ if (read_bit()) // Stopbit(0)
+ return -3;
+ return data;
+}
+
+// send state of LEDs
+void adb_host_kbd_led(uint8_t led)
+{
+ attention();
+ send_byte(0x2A); // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
+ place_bit0(); // Stopbit(0)
+ _delay_us(200); // Tlt/Stop to Start
+ place_bit1(); // Startbit(1)
+ send_byte(0); // send upper byte (not used)
+ send_byte(led&0x07); // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0: NumLock)
+ place_bit0(); // Stopbit(0);
+}
+
+
+static inline void data_lo()
+{
+ ADB_DDR |= (1<<ADB_DATA_BIT);
+ ADB_PORT &= ~(1<<ADB_DATA_BIT);
+}
+static inline void data_hi()
+{
+ ADB_PORT |= (1<<ADB_DATA_BIT);
+ ADB_DDR &= ~(1<<ADB_DATA_BIT);
+}
+static inline bool data_in()
+{
+ ADB_PORT |= (1<<ADB_DATA_BIT);
+ ADB_DDR &= ~(1<<ADB_DATA_BIT);
+ return ADB_PIN&(1<<ADB_DATA_BIT);
+}
+
+#ifdef ADB_PSW_BIT
+static inline void psw_lo()
+{
+ ADB_DDR |= (1<<ADB_PSW_BIT);
+ ADB_PORT &= ~(1<<ADB_PSW_BIT);
+}
+static inline void psw_hi()
+{
+ ADB_PORT |= (1<<ADB_PSW_BIT);
+ ADB_DDR &= ~(1<<ADB_PSW_BIT);
+}
+static inline bool psw_in()
+{
+ ADB_PORT |= (1<<ADB_PSW_BIT);
+ ADB_DDR &= ~(1<<ADB_PSW_BIT);
+ return ADB_PIN&(1<<ADB_PSW_BIT);
+}
+#endif
+
+static inline void attention(void)
+{
+ data_lo();
+ _delay_us(700);
+ place_bit1();
+}
+
+static inline void place_bit0(void)
+{
+ data_lo();
+ _delay_us(65);
+ data_hi();
+ _delay_us(35);
+}
+
+static inline void place_bit1(void)
+{
+ data_lo();
+ _delay_us(35);
+ data_hi();
+ _delay_us(65);
+}
+
+static inline void send_byte(uint8_t data)
+{
+ for (int i = 0; i < 8; i++) {
+ if (data&(0x80>>i))
+ place_bit1();
+ else
+ place_bit0();
+ }
+}
+
+static inline bool read_bit(void)
+{
+ // ADB Bit Cells
+ //
+ // bit0: ______~~~
+ // 65 :35us
+ //
+ // bit1: ___~~~~~~
+ // 35 :65us
+ //
+ // bit0 low time: 60-70% of bit cell(42-91us)
+ // bit1 low time: 30-40% of bit cell(21-52us)
+ // bit cell time: 70-130us
+ // [from Apple IIgs Hardware Reference Second Edition]
+ //
+ // After 55us if data line is low/high then bit is 0/1.
+ // Too simple to rely on?
+ bool bit;
+ wait_data_lo(75); // wait the beginning of bit cell
+ _delay_us(55);
+ bit = data_in();
+ wait_data_hi(36); // wait high part of bit cell
+ return bit;
+}
+
+static inline uint8_t read_byte(void)
+{
+ uint8_t data = 0;
+ for (int i = 0; i < 8; i++) {
+ data <<= 1;
+ if (read_bit())
+ data = data | 1;
+ }
+ return data;
+}
+
+static inline uint8_t wait_data_lo(uint8_t us)
+{
+ while (data_in() && us) {
+ _delay_us(1);
+ us--;
+ }
+ return us;
+}
+
+static inline uint8_t wait_data_hi(uint8_t us)
+{
+ while (!data_in() && us) {
+ _delay_us(1);
+ us--;
+ }
+ return us;
+}
+
+
+/*
+ADB Protocol
+============
+
+Resources
+---------
+ADB - The Untold Story: Space Aliens Ate My Mouse
+ http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
+Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)]
+ ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
+ADB Keycode
+ http://72.0.193.250/Documentation/macppc/adbkeycodes/
+ http://m0115.web.fc2.com/m0115.jpg
+ [Inside Macintosh volume V, pages 191-192]
+ADB Signaling
+ http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
+ADB Overview & History
+ http://en.wikipedia.org/wiki/Apple_Desktop_Bus
+Microchip Application Note: ADB device(with code for PIC16C)
+ http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
+AVR ATtiny2131 ADB to PS/2 converter(Japanese)
+ http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
+
+
+Pinouts
+-------
+ ADB female socket from the front:
+ __________
+ | | <--- top
+ | 4o o3 |
+ |2o o1|
+ | == |
+ |________| <--- bottom
+ | | <--- 4pins
+
+
+ ADB female socket from bottom:
+
+ ========== <--- front
+ | |
+ | |
+ |2o o1|
+ |4o o3|
+ ---------- <--- back
+
+ 1: Data
+ 2: Power SW(low when press Power key)
+ 3: Vcc(5V)
+ 4: GND
+
+
+Commands
+--------
+ ADB command is 1byte and consists of 4bit-address, 2bit-command
+ type and 2bit-register. The commands are always sent by Host.
+
+ Command format:
+ 7 6 5 4 3 2 1 0
+ | | | |------------ address
+ | |-------- command type
+ | |---- register
+
+ bits commands
+ ------------------------------------------------------
+ - - - - 0 0 0 0 Send Request(reset all devices)
+ A A A A 0 0 0 1 Flush(reset a device)
+ - - - - 0 0 1 0 Reserved
+ - - - - 0 0 1 1 Reserved
+ - - - - 0 1 - - Reserved
+ A A A A 1 0 R R Listen(write to a device)
+ A A A A 1 1 R R Talk(read from a device)
+
+ The command to read keycodes from keyboard is 0x2C which
+ consist of keyboard address 2 and Talk against register 0.
+
+ Address:
+ 2: keyboard
+ 3: mice
+
+ Registers:
+ 0: application(keyobard uses this to store its data.)
+ 1: application
+ 2: application(keyboard uses this for LEDs and state of modifiers)
+ 3: status and command
+
+
+Communication
+-------------
+ This is a minimum information for keyboard communication.
+ See "Resources" for detail.
+
+ Signaling:
+
+ ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~
+
+ |800us | |7 Command 0| | | |15-64 Data 0|Stopbit(0)
+ +Attention | | | +Startbit(1)
+ +Startbit(1) | +Tlt(140-260us)
+ +stopbit(0)
+
+ Bit cells:
+
+ bit0: ______~~~
+ 65 :35us
+
+ bit1: ___~~~~~~
+ 35 :65us
+
+ bit0 low time: 60-70% of bit cell(42-91us)
+ bit1 low time: 30-40% of bit cell(21-52us)
+ bit cell time: 70-130us
+ [from Apple IIgs Hardware Reference Second Edition]
+
+ Criterion for bit0/1:
+ After 55us if line is low/high then bit is 0/1.
+
+ Attention & start bit:
+ Host asserts low in 560-1040us then places start bit(1).
+
+ Tlt(Stop to Start):
+ Bus stays high in 140-260us then device places start bit(1).
+
+ Global reset:
+ Host asserts low in 2.8-5.2ms. All devices are forced to reset.
+
+ Send request from device(Srq):
+ Device can request to send at commad(Global only?) stop bit.
+ keep low for 300us to request.
+
+
+Keyboard Data(Register0)
+ This 16bit data can contains two keycodes and two released flags.
+ First keycode is palced in upper byte. When one keyocode is sent,
+ lower byte is 0xFF.
+ Release flag is 1 when key is released.
+
+ 1514 . . . . . 8 7 6 . . . . . 0
+ | | | | | | | | | +-+-+-+-+-+-+- Keycode2
+ | | | | | | | | +--------------- Released2(1 when the key is released)
+ | +-+-+-+-+-+-+----------------- Keycode1
+ +------------------------------- Released1(1 when the key is released)
+
+ Keycodes:
+ Scancode consists of 7bit keycode and 1bit release flag.
+ Device can send two keycodes at once. If just one keycode is sent
+ keycode1 contains it and keyocode2 is 0xFF.
+
+ Power switch:
+ You can read the state from PSW line(active low) however
+ the switch has a special scancode 0x7F7F, so you can
+ also read from Data line. It uses 0xFFFF for release scancode.
+ Release code seems to delay about some 100ms. Due to Mac soft power?
+
+Keyboard LEDs & state of keys(Register2)
+ This register hold current state of three LEDs and nine keys.
+ The state of LEDs can be changed by sending Listen command.
+
+ 1514 . . . . . . 7 6 5 . 3 2 1 0
+ | | | | | | | | | | | | | | | +- LED1(NumLock)
+ | | | | | | | | | | | | | | +--- LED2(CapsLock)
+ | | | | | | | | | | | | | +----- LED3(ScrollLock)
+ | | | | | | | | | | +-+-+------- Reserved
+ | | | | | | | | | +------------- ScrollLock
+ | | | | | | | | +--------------- NumLock
+ | | | | | | | +----------------- Apple/Command
+ | | | | | | +------------------- Option
+ | | | | | +--------------------- Shift
+ | | | | +----------------------- Control
+ | | | +------------------------- Reset/Power
+ | | +--------------------------- CapsLock
+ | +----------------------------- Delete
+ +------------------------------- Reserved
+
+END_OF_ADB
+*/