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     // Enable keyboard left/right modifier distinction
  72     // Addr:Keyboard(0010), Cmd:Listen(10), Register3(11)
  73     // upper byte: reserved bits 0000, device address 0010
  74     // lower byte: device handler 00000011
  75     adb_host_listen(0x2B,0x02,0x03);
  76 }
  77
  78 #ifdef ADB_PSW_BIT
  79 bool adb_host_psw(void)
  80 {
  81     return psw_in();
  82 }
  83 #endif
  84
  85 uint16_t adb_host_kbd_recv(void)
  86 {
  87     uint16_t data = 0;
  88     attention();
  89     send_byte(0x2C);            // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
  90     place_bit0();               // Stopbit(0)
  91     if (!wait_data_lo(0xFF))    // Tlt/Stop to Start(140-260us)
  92         return 0;               // No data to send
  93     if (!read_bit())            // Startbit(1)
  94         return -2;
  95
  96     // ad hoc fix: without block inerrupt read wrong bit occasionally and get keys stuck
  97     cli();
  98     data = read_byte();
  99     data = (data<<8) | read_byte();
 100     sei();
 101
 102     if (read_bit())             // Stopbit(0)
 103         return -3;
 104     return data;
 105 }
 106
 107 void adb_host_listen(uint8_t cmd, uint8_t data_h, uint8_t data_l)
 108 {
 109     attention();
 110     send_byte(cmd);
 111     place_bit0();               // Stopbit(0)
 112     _delay_us(200);             // Tlt/Stop to Start
 113     place_bit1();               // Startbit(1)
 114     send_byte(data_h);
 115     send_byte(data_l);
 116     place_bit0();               // Stopbit(0);
 117 }
 118
 119 // send state of LEDs
 120 void adb_host_kbd_led(uint8_t led)
 121 {
 122     // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
 123     // send upper byte (not used)
 124     // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0:
 125     adb_host_listen(0x2A,0,led&0x07);
 126 }
 127
 128
 129 static inline void data_lo()
 130 {
 131     ADB_DDR  |=  (1<<ADB_DATA_BIT);
 132     ADB_PORT &= ~(1<<ADB_DATA_BIT);
 133 }
 134 static inline void data_hi()
 135 {
 136     ADB_PORT |=  (1<<ADB_DATA_BIT);
 137     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 138 }
 139 static inline bool data_in()
 140 {
 141     ADB_PORT |=  (1<<ADB_DATA_BIT);
 142     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 143     return ADB_PIN&(1<<ADB_DATA_BIT);
 144 }
 145
 146 #ifdef ADB_PSW_BIT
 147 static inline void psw_lo()
 148 {
 149     ADB_DDR  |=  (1<<ADB_PSW_BIT);
 150     ADB_PORT &= ~(1<<ADB_PSW_BIT);
 151 }
 152 static inline void psw_hi()
 153 {
 154     ADB_PORT |=  (1<<ADB_PSW_BIT);
 155     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 156 }
 157 static inline bool psw_in()
 158 {
 159     ADB_PORT |=  (1<<ADB_PSW_BIT);
 160     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 161     return ADB_PIN&(1<<ADB_PSW_BIT);
 162 }
 163 #endif
 164
 165 static inline void attention(void)
 166 {
 167     data_lo();
 168     _delay_us(700);
 169     place_bit1();
 170 }
 171
 172 static inline void place_bit0(void)
 173 {
 174     data_lo();
 175     _delay_us(65);
 176     data_hi();
 177     _delay_us(35);
 178 }
 179
 180 static inline void place_bit1(void)
 181 {
 182     data_lo();
 183     _delay_us(35);
 184     data_hi();
 185     _delay_us(65);
 186 }
 187
 188 static inline void send_byte(uint8_t data)
 189 {
 190     for (int i = 0; i < 8; i++) {
 191         if (data&(0x80>>i))
 192             place_bit1();
 193         else
 194             place_bit0();
 195     }
 196 }
 197
 198 static inline bool read_bit(void)
 199 {
 200     // ADB Bit Cells
 201     //
 202     // bit cell time: 70-130us
 203     // low part of bit0: 60-70% of bit cell
 204     // low part of bit1: 30-40% of bit cell
 205     //
 206     //    bit cell time         70us        130us
 207     //    --------------------------------------------
 208     //    low  part of bit0     42-49       78-91
 209     //    high part of bit0     21-28       39-52
 210     //    low  part of bit1     21-28       39-52
 211     //    high part of bit1     42-49       78-91
 212     //
 213     //
 214     // bit0:
 215     //    70us bit cell:
 216     //      ____________~~~~~~
 217     //      42-49        21-28
 218     //
 219     //    130us bit cell:
 220     //      ____________~~~~~~
 221     //      78-91        39-52
 222     //
 223     // bit1:
 224     //    70us bit cell:
 225     //      ______~~~~~~~~~~~~
 226     //      21-28        42-49
 227     //
 228     //    130us bit cell:
 229     //      ______~~~~~~~~~~~~
 230     //      39-52        78-91
 231     //
 232     // read:
 233     //      ________|~~~~~~~~~
 234     //              55us
 235     // Read data line after 55us. If data line is low/high then bit is 0/1.
 236     // This method might not work at <90us bit cell time.
 237     //
 238     // [from Apple IIgs Hardware Reference Second Edition]
 239     bool bit;
 240     wait_data_lo(75);   // wait the start of bit cell at least 130ms(55+0+75)
 241     _delay_us(55);
 242     bit = data_in();
 243     wait_data_hi(36);   // wait high part of bit cell at least 91ms(55+36)
 244     return bit;
 245 }
 246
 247 static inline uint8_t read_byte(void)
 248 {
 249     uint8_t data = 0;
 250     for (int i = 0; i < 8; i++) {
 251         data <<= 1;
 252         if (read_bit())
 253             data = data | 1;
 254     }
 255     return data;
 256 }
 257
 258 static inline uint8_t wait_data_lo(uint8_t us)
 259 {
 260     while (data_in() && us) {
 261         _delay_us(1);
 262         us--;
 263     }
 264     return us;
 265 }
 266
 267 static inline uint8_t wait_data_hi(uint8_t us)
 268 {
 269     while (!data_in() && us) {
 270         _delay_us(1);
 271         us--;
 272     }
 273     return us;
 274 }
 275
 276
 277 /*
 278 ADB Protocol
 279 ============
 280
 281 Resources
 282 ---------
 283 ADB - The Untold Story: Space Aliens Ate My Mouse
 284     http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
 285 Apple IIgs Hardware Reference Second Edition [Chapter6 p121]
 286     ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
 287 ADB Keycode
 288     http://72.0.193.250/Documentation/macppc/adbkeycodes/
 289     http://m0115.web.fc2.com/m0115.jpg
 290     [Inside Macintosh volume V, pages 191-192]
 291     http://www.opensource.apple.com/source/IOHIDFamily/IOHIDFamily-421.18.3/IOHIDFamily/Cosmo_USB2ADB.c
 292 ADB Signaling
 293     http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
 294 ADB Overview & History
 295     http://en.wikipedia.org/wiki/Apple_Desktop_Bus
 296 Microchip Application Note: ADB device(with code for PIC16C)
 297     http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
 298 AVR ATtiny2131 ADB to PS/2 converter(Japanese)
 299     http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
 300
 301
 302 Pinouts
 303 -------
 304     ADB female socket from the front:
 305     __________
 306     |        | <--- top
 307     | 4o  o3 |
 308     |2o    o1|
 309     |   ==   |
 310     |________| <--- bottom
 311       |    |   <--- 4pins
 312
 313
 314     ADB female socket from bottom:
 315
 316     ========== <--- front
 317     |        |
 318     |        |
 319     |2o    o1|
 320     |4o    o3|
 321     ---------- <--- back
 322
 323     1: Data
 324     2: Power SW(low when press Power key)
 325     3: Vcc(5V)
 326     4: GND
 327
 328
 329 Commands
 330 --------
 331     ADB command is 1byte and consists of 4bit-address, 2bit-command
 332     type and 2bit-register. The commands are always sent by Host.
 333
 334     Command format:
 335     7 6 5 4 3 2 1 0
 336     | | | |------------ address
 337             | |-------- command type
 338                 | |---- register
 339
 340     bits                commands
 341     ------------------------------------------------------
 342     - - - - 0 0 0 0     Send Request(reset all devices)
 343     A A A A 0 0 0 1     Flush(reset a device)
 344     - - - - 0 0 1 0     Reserved
 345     - - - - 0 0 1 1     Reserved
 346     - - - - 0 1 - -     Reserved
 347     A A A A 1 0 R R     Listen(write to a device)
 348     A A A A 1 1 R R     Talk(read from a device)
 349
 350     The command to read keycodes from keyboard is 0x2C which
 351     consist of keyboard address 2 and Talk against register 0.
 352
 353     Address:
 354     2:  keyboard
 355     3:  mice
 356
 357     Registers:
 358     0: application(keyobard uses this to store its data.)
 359     1: application
 360     2: application(keyboard uses this for LEDs and state of modifiers)
 361     3: status and command
 362
 363
 364 Communication
 365 -------------
 366     This is a minimum information for keyboard communication.
 367     See "Resources" for detail.
 368
 369     Signaling:
 370
 371     ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~
 372
 373         |800us     |  |7 Command 0|  |   |  |15-64  Data  0|Stopbit(0)
 374         +Attention |              |  |   +Startbit(1)
 375                    +Startbit(1)   |  +Tlt(140-260us)
 376                                   +stopbit(0)
 377
 378     Bit cells:
 379
 380     bit0: ______~~~
 381           65    :35us
 382
 383     bit1: ___~~~~~~
 384           35 :65us
 385
 386     bit0 low time: 60-70% of bit cell(42-91us)
 387     bit1 low time: 30-40% of bit cell(21-52us)
 388     bit cell time: 70-130us
 389     [from Apple IIgs Hardware Reference Second Edition]
 390
 391     Criterion for bit0/1:
 392     After 55us if line is low/high then bit is 0/1.
 393
 394     Attention & start bit:
 395     Host asserts low in 560-1040us then places start bit(1).
 396
 397     Tlt(Stop to Start):
 398     Bus stays high in 140-260us then device places start bit(1).
 399
 400     Global reset:
 401     Host asserts low in 2.8-5.2ms. All devices are forced to reset.
 402
 403     Service request from device(Srq):
 404     Device can request to send at commad(Global only?) stop bit.
 405     Requesting device keeps low for 140-260us at stop bit of command.
 406
 407
 408 Keyboard Data(Register0)
 409     This 16bit data can contains two keycodes and two released flags.
 410     First keycode is palced in upper byte. When one keyocode is sent,
 411     lower byte is 0xFF.
 412     Release flag is 1 when key is released.
 413
 414     1514 . . . . . 8 7 6 . . . . . 0
 415      | | | | | | | | | +-+-+-+-+-+-+-   Keycode2
 416      | | | | | | | | +---------------   Released2(1 when the key is released)
 417      | +-+-+-+-+-+-+-----------------   Keycode1
 418      +-------------------------------   Released1(1 when the key is released)
 419
 420     Keycodes:
 421     Scancode consists of 7bit keycode and 1bit release flag.
 422     Device can send two keycodes at once. If just one keycode is sent
 423     keycode1 contains it and keyocode2 is 0xFF.
 424
 425     Power switch:
 426     You can read the state from PSW line(active low) however
 427     the switch has a special scancode 0x7F7F, so you can
 428     also read from Data line. It uses 0xFFFF for release scancode.
 429
 430 Keyboard LEDs & state of keys(Register2)
 431     This register hold current state of three LEDs and nine keys.
 432     The state of LEDs can be changed by sending Listen command.
 433
 434     1514 . . . . . . 7 6 5 . 3 2 1 0
 435      | | | | | | | | | | | | | | | +-   LED1(NumLock)
 436      | | | | | | | | | | | | | | +---   LED2(CapsLock)
 437      | | | | | | | | | | | | | +-----   LED3(ScrollLock)
 438      | | | | | | | | | | +-+-+-------   Reserved
 439      | | | | | | | | | +-------------   ScrollLock
 440      | | | | | | | | +---------------   NumLock
 441      | | | | | | | +-----------------   Apple/Command
 442      | | | | | | +-------------------   Option
 443      | | | | | +---------------------   Shift
 444      | | | | +-----------------------   Control
 445      | | | +-------------------------   Reset/Power
 446      | | +---------------------------   CapsLock
 447      | +-----------------------------   Delete
 448      +-------------------------------   Reserved
 449
 450 END_OF_ADB
 451 */