protocol/adb.c

   1 /*
   2 Copyright 2011 Jun WAKO <wakojun@gmail.com>
   3
   4 This software is licensed with a Modified BSD License.
   5 All of this is supposed to be Free Software, Open Source, DFSG-free,
   6 GPL-compatible, and OK to use in both free and proprietary applications.
   7 Additions and corrections to this file are welcome.
   8
   9
  10 Redistribution and use in source and binary forms, with or without
  11 modification, are permitted provided that the following conditions are met:
  12
  13 * Redistributions of source code must retain the above copyright
  14   notice, this list of conditions and the following disclaimer.
  15
  16 * Redistributions in binary form must reproduce the above copyright
  17   notice, this list of conditions and the following disclaimer in
  18   the documentation and/or other materials provided with the
  19   distribution.
  20
  21 * Neither the name of the copyright holders nor the names of
  22   contributors may be used to endorse or promote products derived
  23   from this software without specific prior written permission.
  24
  25 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  26 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  27 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  28 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  29 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  30 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  31 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  32 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  33 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  34 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  35 POSSIBILITY OF SUCH DAMAGE.
  36 */
  37
  38 #include <stdbool.h>
  39 #include <util/delay.h>
  40 #include <avr/io.h>
  41 #include <avr/interrupt.h>
  42 #include "adb.h"
  43
  44
  45 static inline void data_lo(void);
  46 static inline void data_hi(void);
  47 static inline bool data_in(void);
  48 #ifdef ADB_PSW_BIT
  49 static inline void psw_lo(void);
  50 static inline void psw_hi(void);
  51 static inline bool psw_in(void);
  52 #endif
  53
  54 static inline void attention(void);
  55 static inline void place_bit0(void);
  56 static inline void place_bit1(void);
  57 static inline void send_byte(uint8_t data);
  58 static inline bool read_bit(void);
  59 static inline uint8_t read_byte(void);
  60 static inline uint8_t wait_data_lo(uint8_t us);
  61 static inline uint8_t wait_data_hi(uint8_t us);
  62
  63
  64 void adb_host_init(void)
  65 {
  66     data_hi();
  67 #ifdef ADB_PSW_BIT
  68     psw_hi();
  69 #endif
  70 }
  71
  72 #ifdef ADB_PSW_BIT
  73 bool adb_host_psw(void)
  74 {
  75     return psw_in();
  76 }
  77 #endif
  78
  79 uint16_t adb_host_kbd_recv(void)
  80 {
  81     uint16_t data = 0;
  82     attention();
  83     send_byte(0x2C);            // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
  84     place_bit0();               // Stopbit(0)
  85     if (!wait_data_lo(0xFF))    // Tlt/Stop to Start(140-260us)
  86         return 0;               // No data to send
  87     if (!read_bit())            // Startbit(1)
  88         return -2;
  89
  90     // ad hoc fix: without block inerrupt read wrong bit occasionally and get keys stuck
  91     cli();
  92     data = read_byte();
  93     data = (data<<8) | read_byte();
  94     sei();
  95
  96     if (read_bit())             // Stopbit(0)
  97         return -3;
  98     return data;
  99 }
 100
 101 // send state of LEDs
 102 void adb_host_kbd_led(uint8_t led)
 103 {
 104     attention();
 105     send_byte(0x2A);            // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
 106     place_bit0();               // Stopbit(0)
 107     _delay_us(200);             // Tlt/Stop to Start
 108     place_bit1();               // Startbit(1)
 109     send_byte(0);               // send upper byte (not used)
 110     send_byte(led&0x07);        // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0: NumLock)
 111     place_bit0();               // Stopbit(0);
 112 }
 113
 114
 115 static inline void data_lo()
 116 {
 117     ADB_DDR  |=  (1<<ADB_DATA_BIT);
 118     ADB_PORT &= ~(1<<ADB_DATA_BIT);
 119 }
 120 static inline void data_hi()
 121 {
 122     ADB_PORT |=  (1<<ADB_DATA_BIT);
 123     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 124 }
 125 static inline bool data_in()
 126 {
 127     ADB_PORT |=  (1<<ADB_DATA_BIT);
 128     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 129     return ADB_PIN&(1<<ADB_DATA_BIT);
 130 }
 131
 132 #ifdef ADB_PSW_BIT
 133 static inline void psw_lo()
 134 {
 135     ADB_DDR  |=  (1<<ADB_PSW_BIT);
 136     ADB_PORT &= ~(1<<ADB_PSW_BIT);
 137 }
 138 static inline void psw_hi()
 139 {
 140     ADB_PORT |=  (1<<ADB_PSW_BIT);
 141     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 142 }
 143 static inline bool psw_in()
 144 {
 145     ADB_PORT |=  (1<<ADB_PSW_BIT);
 146     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 147     return ADB_PIN&(1<<ADB_PSW_BIT);
 148 }
 149 #endif
 150
 151 static inline void attention(void)
 152 {
 153     data_lo();
 154     _delay_us(700);
 155     place_bit1();
 156 }
 157
 158 static inline void place_bit0(void)
 159 {
 160     data_lo();
 161     _delay_us(65);
 162     data_hi();
 163     _delay_us(35);
 164 }
 165
 166 static inline void place_bit1(void)
 167 {
 168     data_lo();
 169     _delay_us(35);
 170     data_hi();
 171     _delay_us(65);
 172 }
 173
 174 static inline void send_byte(uint8_t data)
 175 {
 176     for (int i = 0; i < 8; i++) {
 177         if (data&(0x80>>i))
 178             place_bit1();
 179         else
 180             place_bit0();
 181     }
 182 }
 183
 184 static inline bool read_bit(void)
 185 {
 186     // ADB Bit Cells
 187     //
 188     // bit0: ______~~~
 189     //       65    :35us
 190     //
 191     // bit1: ___~~~~~~
 192     //       35 :65us
 193     //
 194     // bit0 low time: 60-70% of bit cell(42-91us)
 195     // bit1 low time: 30-40% of bit cell(21-52us)
 196     // bit cell time: 70-130us
 197     // [from Apple IIgs Hardware Reference Second Edition]
 198     //
 199     // After 55us if data line is low/high then bit is 0/1.
 200     // Too simple to rely on?
 201     bool bit;
 202     wait_data_lo(75);   // wait the beginning of bit cell
 203     _delay_us(55);
 204     bit = data_in();
 205     wait_data_hi(36);   // wait high part of bit cell
 206     return bit;
 207 }
 208
 209 static inline uint8_t read_byte(void)
 210 {
 211     uint8_t data = 0;
 212     for (int i = 0; i < 8; i++) {
 213         data <<= 1;
 214         if (read_bit())
 215             data = data | 1;
 216     }
 217     return data;
 218 }
 219
 220 static inline uint8_t wait_data_lo(uint8_t us)
 221 {
 222     while (data_in() && us) {
 223         _delay_us(1);
 224         us--;
 225     }
 226     return us;
 227 }
 228
 229 static inline uint8_t wait_data_hi(uint8_t us)
 230 {
 231     while (!data_in() && us) {
 232         _delay_us(1);
 233         us--;
 234     }
 235     return us;
 236 }
 237
 238
 239 /*
 240 ADB Protocol
 241 ============
 242
 243 Resources
 244 ---------
 245 ADB - The Untold Story: Space Aliens Ate My Mouse
 246     http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
 247 Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)]
 248     ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
 249 ADB Keycode
 250     http://72.0.193.250/Documentation/macppc/adbkeycodes/
 251     http://m0115.web.fc2.com/m0115.jpg
 252     [Inside Macintosh volume V, pages 191-192]
 253 ADB Signaling
 254     http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
 255 ADB Overview & History
 256     http://en.wikipedia.org/wiki/Apple_Desktop_Bus
 257 Microchip Application Note: ADB device(with code for PIC16C)
 258     http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
 259 AVR ATtiny2131 ADB to PS/2 converter(Japanese)
 260     http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
 261
 262
 263 Pinouts
 264 -------
 265     ADB female socket from the front:
 266     __________
 267     |        | <--- top
 268     | 4o  o3 |
 269     |2o    o1|
 270     |   ==   |
 271     |________| <--- bottom
 272       |    |   <--- 4pins
 273
 274
 275     ADB female socket from bottom:
 276
 277     ========== <--- front
 278     |        |
 279     |        |
 280     |2o    o1|
 281     |4o    o3|
 282     ---------- <--- back
 283
 284     1: Data
 285     2: Power SW(low when press Power key)
 286     3: Vcc(5V)
 287     4: GND
 288
 289
 290 Commands
 291 --------
 292     ADB command is 1byte and consists of 4bit-address, 2bit-command
 293     type and 2bit-register. The commands are always sent by Host.
 294
 295     Command format:
 296     7 6 5 4 3 2 1 0
 297     | | | |------------ address
 298             | |-------- command type
 299                 | |---- register
 300
 301     bits                commands
 302     ------------------------------------------------------
 303     - - - - 0 0 0 0     Send Request(reset all devices)
 304     A A A A 0 0 0 1     Flush(reset a device)
 305     - - - - 0 0 1 0     Reserved
 306     - - - - 0 0 1 1     Reserved
 307     - - - - 0 1 - -     Reserved
 308     A A A A 1 0 R R     Listen(write to a device)
 309     A A A A 1 1 R R     Talk(read from a device)
 310
 311     The command to read keycodes from keyboard is 0x2C which
 312     consist of keyboard address 2 and Talk against register 0.
 313
 314     Address:
 315     2:  keyboard
 316     3:  mice
 317
 318     Registers:
 319     0: application(keyobard uses this to store its data.)
 320     1: application
 321     2: application(keyboard uses this for LEDs and state of modifiers)
 322     3: status and command
 323
 324
 325 Communication
 326 -------------
 327     This is a minimum information for keyboard communication.
 328     See "Resources" for detail.
 329
 330     Signaling:
 331
 332     ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~
 333
 334         |800us     |  |7 Command 0|  |   |  |15-64  Data  0|Stopbit(0)
 335         +Attention |              |  |   +Startbit(1)
 336                    +Startbit(1)   |  +Tlt(140-260us)
 337                                   +stopbit(0)
 338
 339     Bit cells:
 340
 341     bit0: ______~~~
 342           65    :35us
 343
 344     bit1: ___~~~~~~
 345           35 :65us
 346
 347     bit0 low time: 60-70% of bit cell(42-91us)
 348     bit1 low time: 30-40% of bit cell(21-52us)
 349     bit cell time: 70-130us
 350     [from Apple IIgs Hardware Reference Second Edition]
 351
 352     Criterion for bit0/1:
 353     After 55us if line is low/high then bit is 0/1.
 354
 355     Attention & start bit:
 356     Host asserts low in 560-1040us then places start bit(1).
 357
 358     Tlt(Stop to Start):
 359     Bus stays high in 140-260us then device places start bit(1).
 360
 361     Global reset:
 362     Host asserts low in 2.8-5.2ms. All devices are forced to reset.
 363
 364     Send request from device(Srq):
 365     Device can request to send at commad(Global only?) stop bit.
 366     keep low for 300us to request.
 367
 368
 369 Keyboard Data(Register0)
 370     This 16bit data can contains two keycodes and two released flags.
 371     First keycode is palced in upper byte. When one keyocode is sent,
 372     lower byte is 0xFF.
 373     Release flag is 1 when key is released.
 374
 375     1514 . . . . . 8 7 6 . . . . . 0
 376      | | | | | | | | | +-+-+-+-+-+-+-   Keycode2
 377      | | | | | | | | +---------------   Released2(1 when the key is released)
 378      | +-+-+-+-+-+-+-----------------   Keycode1
 379      +-------------------------------   Released1(1 when the key is released)
 380
 381     Keycodes:
 382     Scancode consists of 7bit keycode and 1bit release flag.
 383     Device can send two keycodes at once. If just one keycode is sent
 384     keycode1 contains it and keyocode2 is 0xFF.
 385
 386     Power switch:
 387     You can read the state from PSW line(active low) however
 388     the switch has a special scancode 0x7F7F, so you can
 389     also read from Data line. It uses 0xFFFF for release scancode.
 390
 391 Keyboard LEDs & state of keys(Register2)
 392     This register hold current state of three LEDs and nine keys.
 393     The state of LEDs can be changed by sending Listen command.
 394
 395     1514 . . . . . . 7 6 5 . 3 2 1 0
 396      | | | | | | | | | | | | | | | +-   LED1(NumLock)
 397      | | | | | | | | | | | | | | +---   LED2(CapsLock)
 398      | | | | | | | | | | | | | +-----   LED3(ScrollLock)
 399      | | | | | | | | | | +-+-+-------   Reserved
 400      | | | | | | | | | +-------------   ScrollLock
 401      | | | | | | | | +---------------   NumLock
 402      | | | | | | | +-----------------   Apple/Command
 403      | | | | | | +-------------------   Option
 404      | | | | | +---------------------   Shift
 405      | | | | +-----------------------   Control
 406      | | | +-------------------------   Reset/Power
 407      | | +---------------------------   CapsLock
 408      | +-----------------------------   Delete
 409      +-------------------------------   Reserved
 410
 411 END_OF_ADB
 412 */