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     // bit0: ______~~~
 203     //       65    :35us
 204     //
 205     // bit1: ___~~~~~~
 206     //       35 :65us
 207     //
 208     // bit0 low time: 60-70% of bit cell(42-91us)
 209     // bit1 low time: 30-40% of bit cell(21-52us)
 210     // bit cell time: 70-130us
 211     // [from Apple IIgs Hardware Reference Second Edition]
 212     //
 213     // After 55us if data line is low/high then bit is 0/1.
 214     // Too simple to rely on?
 215     bool bit;
 216     wait_data_lo(75);   // wait the beginning of bit cell
 217     _delay_us(55);
 218     bit = data_in();
 219     wait_data_hi(36);   // wait high part of bit cell
 220     return bit;
 221 }
 222
 223 static inline uint8_t read_byte(void)
 224 {
 225     uint8_t data = 0;
 226     for (int i = 0; i < 8; i++) {
 227         data <<= 1;
 228         if (read_bit())
 229             data = data | 1;
 230     }
 231     return data;
 232 }
 233
 234 static inline uint8_t wait_data_lo(uint8_t us)
 235 {
 236     while (data_in() && us) {
 237         _delay_us(1);
 238         us--;
 239     }
 240     return us;
 241 }
 242
 243 static inline uint8_t wait_data_hi(uint8_t us)
 244 {
 245     while (!data_in() && us) {
 246         _delay_us(1);
 247         us--;
 248     }
 249     return us;
 250 }
 251
 252
 253 /*
 254 ADB Protocol
 255 ============
 256
 257 Resources
 258 ---------
 259 ADB - The Untold Story: Space Aliens Ate My Mouse
 260     http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
 261 Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)]
 262     ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
 263 ADB Keycode
 264     http://72.0.193.250/Documentation/macppc/adbkeycodes/
 265     http://m0115.web.fc2.com/m0115.jpg
 266     [Inside Macintosh volume V, pages 191-192]
 267 ADB Signaling
 268     http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
 269 ADB Overview & History
 270     http://en.wikipedia.org/wiki/Apple_Desktop_Bus
 271 Microchip Application Note: ADB device(with code for PIC16C)
 272     http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
 273 AVR ATtiny2131 ADB to PS/2 converter(Japanese)
 274     http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
 275
 276
 277 Pinouts
 278 -------
 279     ADB female socket from the front:
 280     __________
 281     |        | <--- top
 282     | 4o  o3 |
 283     |2o    o1|
 284     |   ==   |
 285     |________| <--- bottom
 286       |    |   <--- 4pins
 287
 288
 289     ADB female socket from bottom:
 290
 291     ========== <--- front
 292     |        |
 293     |        |
 294     |2o    o1|
 295     |4o    o3|
 296     ---------- <--- back
 297
 298     1: Data
 299     2: Power SW(low when press Power key)
 300     3: Vcc(5V)
 301     4: GND
 302
 303
 304 Commands
 305 --------
 306     ADB command is 1byte and consists of 4bit-address, 2bit-command
 307     type and 2bit-register. The commands are always sent by Host.
 308
 309     Command format:
 310     7 6 5 4 3 2 1 0
 311     | | | |------------ address
 312             | |-------- command type
 313                 | |---- register
 314
 315     bits                commands
 316     ------------------------------------------------------
 317     - - - - 0 0 0 0     Send Request(reset all devices)
 318     A A A A 0 0 0 1     Flush(reset a device)
 319     - - - - 0 0 1 0     Reserved
 320     - - - - 0 0 1 1     Reserved
 321     - - - - 0 1 - -     Reserved
 322     A A A A 1 0 R R     Listen(write to a device)
 323     A A A A 1 1 R R     Talk(read from a device)
 324
 325     The command to read keycodes from keyboard is 0x2C which
 326     consist of keyboard address 2 and Talk against register 0.
 327
 328     Address:
 329     2:  keyboard
 330     3:  mice
 331
 332     Registers:
 333     0: application(keyobard uses this to store its data.)
 334     1: application
 335     2: application(keyboard uses this for LEDs and state of modifiers)
 336     3: status and command
 337
 338
 339 Communication
 340 -------------
 341     This is a minimum information for keyboard communication.
 342     See "Resources" for detail.
 343
 344     Signaling:
 345
 346     ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~
 347
 348         |800us     |  |7 Command 0|  |   |  |15-64  Data  0|Stopbit(0)
 349         +Attention |              |  |   +Startbit(1)
 350                    +Startbit(1)   |  +Tlt(140-260us)
 351                                   +stopbit(0)
 352
 353     Bit cells:
 354
 355     bit0: ______~~~
 356           65    :35us
 357
 358     bit1: ___~~~~~~
 359           35 :65us
 360
 361     bit0 low time: 60-70% of bit cell(42-91us)
 362     bit1 low time: 30-40% of bit cell(21-52us)
 363     bit cell time: 70-130us
 364     [from Apple IIgs Hardware Reference Second Edition]
 365
 366     Criterion for bit0/1:
 367     After 55us if line is low/high then bit is 0/1.
 368
 369     Attention & start bit:
 370     Host asserts low in 560-1040us then places start bit(1).
 371
 372     Tlt(Stop to Start):
 373     Bus stays high in 140-260us then device places start bit(1).
 374
 375     Global reset:
 376     Host asserts low in 2.8-5.2ms. All devices are forced to reset.
 377
 378     Send request from device(Srq):
 379     Device can request to send at commad(Global only?) stop bit.
 380     keep low for 300us to request.
 381
 382
 383 Keyboard Data(Register0)
 384     This 16bit data can contains two keycodes and two released flags.
 385     First keycode is palced in upper byte. When one keyocode is sent,
 386     lower byte is 0xFF.
 387     Release flag is 1 when key is released.
 388
 389     1514 . . . . . 8 7 6 . . . . . 0
 390      | | | | | | | | | +-+-+-+-+-+-+-   Keycode2
 391      | | | | | | | | +---------------   Released2(1 when the key is released)
 392      | +-+-+-+-+-+-+-----------------   Keycode1
 393      +-------------------------------   Released1(1 when the key is released)
 394
 395     Keycodes:
 396     Scancode consists of 7bit keycode and 1bit release flag.
 397     Device can send two keycodes at once. If just one keycode is sent
 398     keycode1 contains it and keyocode2 is 0xFF.
 399
 400     Power switch:
 401     You can read the state from PSW line(active low) however
 402     the switch has a special scancode 0x7F7F, so you can
 403     also read from Data line. It uses 0xFFFF for release scancode.
 404
 405 Keyboard LEDs & state of keys(Register2)
 406     This register hold current state of three LEDs and nine keys.
 407     The state of LEDs can be changed by sending Listen command.
 408
 409     1514 . . . . . . 7 6 5 . 3 2 1 0
 410      | | | | | | | | | | | | | | | +-   LED1(NumLock)
 411      | | | | | | | | | | | | | | +---   LED2(CapsLock)
 412      | | | | | | | | | | | | | +-----   LED3(ScrollLock)
 413      | | | | | | | | | | +-+-+-------   Reserved
 414      | | | | | | | | | +-------------   ScrollLock
 415      | | | | | | | | +---------------   NumLock
 416      | | | | | | | +-----------------   Apple/Command
 417      | | | | | | +-------------------   Option
 418      | | | | | +---------------------   Shift
 419      | | | | +-----------------------   Control
 420      | | | +-------------------------   Reset/Power
 421      | | +---------------------------   CapsLock
 422      | +-----------------------------   Delete
 423      +-------------------------------   Reserved
 424
 425 END_OF_ADB
 426 */