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 "adb.h"
  42
  43
  44 static inline void data_lo(void);
  45 static inline void data_hi(void);
  46 static inline bool data_in(void);
  47 #ifdef ADB_PSW_BIT
  48 static inline void psw_lo(void);
  49 static inline void psw_hi(void);
  50 static inline bool psw_in(void);
  51 #endif
  52
  53 static inline void attention(void);
  54 static inline void place_bit0(void);
  55 static inline void place_bit1(void);
  56 static inline void send_byte(uint8_t data);
  57 static inline bool read_bit(void);
  58 static inline uint8_t read_byte(void);
  59 static inline uint8_t wait_data_lo(uint8_t us);
  60 static inline uint8_t wait_data_hi(uint8_t us);
  61
  62
  63 void adb_host_init(void)
  64 {
  65     data_hi();
  66 #ifdef ADB_PSW_BIT
  67     psw_hi();
  68 #endif
  69 }
  70
  71 #ifdef ADB_PSW_BIT
  72 bool adb_host_psw(void)
  73 {
  74     return psw_in();
  75 }
  76 #endif
  77
  78 uint16_t adb_host_kbd_recv(void)
  79 {
  80     uint16_t data = 0;
  81     attention();
  82     send_byte(0x2C);            // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
  83     place_bit0();               // Stopbit(0)
  84     if (!wait_data_lo(0xFF))    // Tlt/Stop to Start(140-260us)
  85         return 0;               // No data to send
  86     if (!read_bit())            // Startbit(1)
  87         return -2;
  88     data = read_byte();
  89     data = (data<<8) | read_byte();
  90     if (read_bit())             // Stopbit(0)
  91         return -3;
  92     return data;
  93 }
  94
  95 // send state of LEDs
  96 void adb_host_kbd_led(uint8_t led)
  97 {
  98     attention();
  99     send_byte(0x2A);            // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
 100     place_bit0();               // Stopbit(0)
 101     _delay_us(200);             // Tlt/Stop to Start
 102     place_bit1();               // Startbit(1)
 103     send_byte(0);               // send upper byte (not used)
 104     send_byte(led&0x07);        // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0: NumLock)
 105     place_bit0();               // Stopbit(0);
 106 }
 107
 108
 109 static inline void data_lo()
 110 {
 111     ADB_DDR  |=  (1<<ADB_DATA_BIT);
 112     ADB_PORT &= ~(1<<ADB_DATA_BIT);
 113 }
 114 static inline void data_hi()
 115 {
 116     ADB_PORT |=  (1<<ADB_DATA_BIT);
 117     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 118 }
 119 static inline bool data_in()
 120 {
 121     ADB_PORT |=  (1<<ADB_DATA_BIT);
 122     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 123     return ADB_PIN&(1<<ADB_DATA_BIT);
 124 }
 125
 126 #ifdef ADB_PSW_BIT
 127 static inline void psw_lo()
 128 {
 129     ADB_DDR  |=  (1<<ADB_PSW_BIT);
 130     ADB_PORT &= ~(1<<ADB_PSW_BIT);
 131 }
 132 static inline void psw_hi()
 133 {
 134     ADB_PORT |=  (1<<ADB_PSW_BIT);
 135     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 136 }
 137 static inline bool psw_in()
 138 {
 139     ADB_PORT |=  (1<<ADB_PSW_BIT);
 140     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 141     return ADB_PIN&(1<<ADB_PSW_BIT);
 142 }
 143 #endif
 144
 145 static inline void attention(void)
 146 {
 147     data_lo();
 148     _delay_us(700);
 149     place_bit1();
 150 }
 151
 152 static inline void place_bit0(void)
 153 {
 154     data_lo();
 155     _delay_us(65);
 156     data_hi();
 157     _delay_us(35);
 158 }
 159
 160 static inline void place_bit1(void)
 161 {
 162     data_lo();
 163     _delay_us(35);
 164     data_hi();
 165     _delay_us(65);
 166 }
 167
 168 static inline void send_byte(uint8_t data)
 169 {
 170     for (int i = 0; i < 8; i++) {
 171         if (data&(0x80>>i))
 172             place_bit1();
 173         else
 174             place_bit0();
 175     }
 176 }
 177
 178 static inline bool read_bit(void)
 179 {
 180     // ADB Bit Cells
 181     //
 182     // bit0: ______~~~
 183     //       65    :35us
 184     //
 185     // bit1: ___~~~~~~
 186     //       35 :65us
 187     //
 188     // bit0 low time: 60-70% of bit cell(42-91us)
 189     // bit1 low time: 30-40% of bit cell(21-52us)
 190     // bit cell time: 70-130us
 191     // [from Apple IIgs Hardware Reference Second Edition]
 192     //
 193     // After 55us if data line is low/high then bit is 0/1.
 194     // Too simple to rely on?
 195     bool bit;
 196     wait_data_lo(75);   // wait the beginning of bit cell
 197     _delay_us(55);
 198     bit = data_in();
 199     wait_data_hi(36);   // wait high part of bit cell
 200     return bit;
 201 }
 202
 203 static inline uint8_t read_byte(void)
 204 {
 205     uint8_t data = 0;
 206     for (int i = 0; i < 8; i++) {
 207         data <<= 1;
 208         if (read_bit())
 209             data = data | 1;
 210     }
 211     return data;
 212 }
 213
 214 static inline uint8_t wait_data_lo(uint8_t us)
 215 {
 216     while (data_in() && us) {
 217         _delay_us(1);
 218         us--;
 219     }
 220     return us;
 221 }
 222
 223 static inline uint8_t wait_data_hi(uint8_t us)
 224 {
 225     while (!data_in() && us) {
 226         _delay_us(1);
 227         us--;
 228     }
 229     return us;
 230 }
 231
 232
 233 /*
 234 ADB Protocol
 235 ============
 236
 237 Resources
 238 ---------
 239 ADB - The Untold Story: Space Aliens Ate My Mouse
 240     http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
 241 Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)]
 242     ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
 243 ADB Keycode
 244     http://72.0.193.250/Documentation/macppc/adbkeycodes/
 245     http://m0115.web.fc2.com/m0115.jpg
 246     [Inside Macintosh volume V, pages 191-192]
 247 ADB Signaling
 248     http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
 249 ADB Overview & History
 250     http://en.wikipedia.org/wiki/Apple_Desktop_Bus
 251 Microchip Application Note: ADB device(with code for PIC16C)
 252     http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
 253 AVR ATtiny2131 ADB to PS/2 converter(Japanese)
 254     http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
 255
 256
 257 Pinouts
 258 -------
 259     ADB female socket from the front:
 260     __________
 261     |        | <--- top
 262     | 4o  o3 |
 263     |2o    o1|
 264     |   ==   |
 265     |________| <--- bottom
 266       |    |   <--- 4pins
 267
 268
 269     ADB female socket from bottom:
 270
 271     ========== <--- front
 272     |        |
 273     |        |
 274     |2o    o1|
 275     |4o    o3|
 276     ---------- <--- back
 277
 278     1: Data
 279     2: Power SW(low when press Power key)
 280     3: Vcc(5V)
 281     4: GND
 282
 283
 284 Commands
 285 --------
 286     ADB command is 1byte and consists of 4bit-address, 2bit-command
 287     type and 2bit-register. The commands are always sent by Host.
 288
 289     Command format:
 290     7 6 5 4 3 2 1 0
 291     | | | |------------ address
 292             | |-------- command type
 293                 | |---- register
 294
 295     bits                commands
 296     ------------------------------------------------------
 297     - - - - 0 0 0 0     Send Request(reset all devices)
 298     A A A A 0 0 0 1     Flush(reset a device)
 299     - - - - 0 0 1 0     Reserved
 300     - - - - 0 0 1 1     Reserved
 301     - - - - 0 1 - -     Reserved
 302     A A A A 1 0 R R     Listen(write to a device)
 303     A A A A 1 1 R R     Talk(read from a device)
 304
 305     The command to read keycodes from keyboard is 0x2C which
 306     consist of keyboard address 2 and Talk against register 0.
 307
 308     Address:
 309     2:  keyboard
 310     3:  mice
 311
 312     Registers:
 313     0: application(keyobard uses this to store its data.)
 314     1: application
 315     2: application(keyboard uses this for LEDs and state of modifiers)
 316     3: status and command
 317
 318
 319 Communication
 320 -------------
 321     This is a minimum information for keyboard communication.
 322     See "Resources" for detail.
 323
 324     Signaling:
 325
 326     ~~~~____________~~||||||||||||__~~~~~_~~|||||||||||||||__~~~~
 327
 328         |800us     |  |7 Command 0|  |   |  |15-64  Data  0|Stopbit(0)
 329         +Attention |              |  |   +Startbit(1)
 330                    +Startbit(1)   |  +Tlt(140-260us)
 331                                   +stopbit(0)
 332
 333     Bit cells:
 334
 335     bit0: ______~~~
 336           65    :35us
 337
 338     bit1: ___~~~~~~
 339           35 :65us
 340
 341     bit0 low time: 60-70% of bit cell(42-91us)
 342     bit1 low time: 30-40% of bit cell(21-52us)
 343     bit cell time: 70-130us
 344     [from Apple IIgs Hardware Reference Second Edition]
 345
 346     Criterion for bit0/1:
 347     After 55us if line is low/high then bit is 0/1.
 348
 349     Attention & start bit:
 350     Host asserts low in 560-1040us then places start bit(1).
 351
 352     Tlt(Stop to Start):
 353     Bus stays high in 140-260us then device places start bit(1).
 354
 355     Global reset:
 356     Host asserts low in 2.8-5.2ms. All devices are forced to reset.
 357
 358     Send request from device(Srq):
 359     Device can request to send at commad(Global only?) stop bit.
 360     keep low for 300us to request.
 361
 362
 363 Keyboard Data(Register0)
 364     This 16bit data can contains two keycodes and two released flags.
 365     First keycode is palced in upper byte. When one keyocode is sent,
 366     lower byte is 0xFF.
 367     Release flag is 1 when key is released.
 368
 369     1514 . . . . . 8 7 6 . . . . . 0
 370      | | | | | | | | | +-+-+-+-+-+-+-   Keycode2
 371      | | | | | | | | +---------------   Released2(1 when the key is released)
 372      | +-+-+-+-+-+-+-----------------   Keycode1
 373      +-------------------------------   Released1(1 when the key is released)
 374
 375     Keycodes:
 376     Scancode consists of 7bit keycode and 1bit release flag.
 377     Device can send two keycodes at once. If just one keycode is sent
 378     keycode1 contains it and keyocode2 is 0xFF.
 379
 380     Power switch:
 381     You can read the state from PSW line(active low) however
 382     the switch has a special scancode 0x7F7F, so you can
 383     also read from Data line. It uses 0xFFFF for release scancode.
 384     Release code seems to delay about some 100ms. Due to Mac soft power?
 385
 386 Keyboard LEDs & state of keys(Register2)
 387     This register hold current state of three LEDs and nine keys.
 388     The state of LEDs can be changed by sending Listen command.
 389
 390     1514 . . . . . . 7 6 5 . 3 2 1 0
 391      | | | | | | | | | | | | | | | +-   LED1(NumLock)
 392      | | | | | | | | | | | | | | +---   LED2(CapsLock)
 393      | | | | | | | | | | | | | +-----   LED3(ScrollLock)
 394      | | | | | | | | | | +-+-+-------   Reserved
 395      | | | | | | | | | +-------------   ScrollLock
 396      | | | | | | | | +---------------   NumLock
 397      | | | | | | | +-----------------   Apple/Command
 398      | | | | | | +-------------------   Option
 399      | | | | | +---------------------   Shift
 400      | | | | +-----------------------   Control
 401      | | | +-------------------------   Reset/Power
 402      | | +---------------------------   CapsLock
 403      | +-----------------------------   Delete
 404      +-------------------------------   Reserved
 405
 406 END_OF_ADB
 407 */