adb.c

   1 /*
   2 Copyright (c) 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 #include <stdbool.h>
  38 #include <util/delay.h>
  39 #include <avr/io.h>
  40 #include "adb.h"
  41
  42
  43 static inline void data_lo(void);
  44 static inline void data_hi(void);
  45 static inline bool data_in(void);
  46 #ifdef ADB_PSW_BIT
  47 static inline void psw_lo(void);
  48 static inline void psw_hi(void);
  49 static inline bool psw_in(void);
  50 #endif
  51
  52 static inline void attention(void);
  53 static inline void place_bit0(void);
  54 static inline void place_bit1(void);
  55 static inline void send_byte(uint8_t data);
  56 static inline bool read_bit(void);
  57 static inline uint8_t read_byte(void);
  58 static inline uint8_t wait_data_lo(uint8_t us);
  59 static inline uint8_t wait_data_hi(uint8_t us);
  60
  61
  62 void adb_host_init(void)
  63 {
  64     data_hi();
  65 #ifdef ADB_PSW_BIT
  66     psw_hi();
  67 #endif
  68 }
  69
  70 #ifdef ADB_PSW_BIT
  71 bool adb_host_psw(void)
  72 {
  73     return psw_in();
  74 }
  75 #endif
  76
  77 uint16_t adb_host_kbd_recv(void)
  78 {
  79     uint16_t data = 0;
  80     attention();
  81     send_byte(0x2C);            // Addr:Keyboard(0010), Cmd:Talk(11), Register0(00)
  82     place_bit0();               // Stopbit(0)
  83     if (!wait_data_lo(0xFF))    // Tlt/Stop to Start(140-260us)
  84         return 0;               // No data to send
  85     if (!read_bit())            // Startbit(1)
  86         return -2;
  87     data = read_byte();
  88     data = (data<<8) | read_byte();
  89     if (read_bit())             // Stopbit(0)
  90         return -3;
  91     return data;
  92 }
  93
  94 // send state of LEDs
  95 void adb_host_kbd_led(uint8_t led)
  96 {
  97     attention();
  98     send_byte(0x2A);            // Addr:Keyboard(0010), Cmd:Listen(10), Register2(10)
  99     place_bit0();               // Stopbit(0)
 100     _delay_us(200);             // Tlt/Stop to Start
 101     place_bit1();               // Startbit(1)
 102     send_byte(0);               // send upper byte (not used)
 103     send_byte(led&0x07);        // send lower byte (bit2: ScrollLock, bit1: CapsLock, bit0: NumLock)
 104     place_bit0();               // Stopbit(0);
 105 }
 106
 107
 108 static inline void data_lo()
 109 {
 110     ADB_DDR  |=  (1<<ADB_DATA_BIT);
 111     ADB_PORT &= ~(1<<ADB_DATA_BIT);
 112 }
 113 static inline void data_hi()
 114 {
 115     ADB_PORT |=  (1<<ADB_DATA_BIT);
 116     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 117 }
 118 static inline bool data_in()
 119 {
 120     ADB_PORT |=  (1<<ADB_DATA_BIT);
 121     ADB_DDR  &= ~(1<<ADB_DATA_BIT);
 122     return ADB_PIN&(1<<ADB_DATA_BIT);
 123 }
 124
 125 #ifdef ADB_PSW_BIT
 126 static inline void psw_lo()
 127 {
 128     ADB_DDR  |=  (1<<ADB_PSW_BIT);
 129     ADB_PORT &= ~(1<<ADB_PSW_BIT);
 130 }
 131 static inline void psw_hi()
 132 {
 133     ADB_PORT |=  (1<<ADB_PSW_BIT);
 134     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 135 }
 136 static inline bool psw_in()
 137 {
 138     ADB_PORT |=  (1<<ADB_PSW_BIT);
 139     ADB_DDR  &= ~(1<<ADB_PSW_BIT);
 140     return ADB_PIN&(1<<ADB_PSW_BIT);
 141 }
 142 #endif
 143
 144 static inline void attention(void)
 145 {
 146     data_lo();
 147     _delay_us(700);
 148     place_bit1();
 149 }
 150
 151 static inline void place_bit0(void)
 152 {
 153     data_lo();
 154     _delay_us(65);
 155     data_hi();
 156     _delay_us(35);
 157 }
 158
 159 static inline void place_bit1(void)
 160 {
 161     data_lo();
 162     _delay_us(35);
 163     data_hi();
 164     _delay_us(65);
 165 }
 166
 167 static inline void send_byte(uint8_t data)
 168 {
 169     for (int i = 0; i < 8; i++) {
 170         if (data&(0x80>>i))
 171             place_bit1();
 172         else
 173             place_bit0();
 174     }
 175 }
 176
 177 static inline bool read_bit(void)
 178 {
 179     // ADB Bit Cells
 180     //
 181     // bit0: ______~~~
 182     //       65    :35us
 183     //
 184     // bit1: ___~~~~~~
 185     //       35 :65us
 186     //
 187     // bit0 low time: 60-70% of bit cell(42-91us)
 188     // bit1 low time: 30-40% of bit cell(21-52us)
 189     // bit cell time: 70-130us
 190     // [from Apple IIgs Hardware Reference Second Edition]
 191     //
 192     // After 55us if data line is low/high then bit is 0/1.
 193     // Too simple to rely on?
 194     bool bit;
 195     wait_data_lo(75);   // wait the beginning of bit cell
 196     _delay_us(55);
 197     bit = data_in();
 198     wait_data_hi(36);   // wait high part of bit cell
 199     return bit;
 200 }
 201
 202 static inline uint8_t read_byte(void)
 203 {
 204     uint8_t data = 0;
 205     for (int i = 0; i < 8; i++) {
 206         data <<= 1;
 207         if (read_bit())
 208             data = data | 1;
 209     }
 210     return data;
 211 }
 212
 213 static inline uint8_t wait_data_lo(uint8_t us)
 214 {
 215     while (data_in() && us) {
 216         _delay_us(1);
 217         us--;
 218     }
 219     return us;
 220 }
 221
 222 static inline uint8_t wait_data_hi(uint8_t us)
 223 {
 224     while (!data_in() && us) {
 225         _delay_us(1);
 226         us--;
 227     }
 228     return us;
 229 }
 230
 231
 232 /*
 233 ADB Protocol
 234 ============
 235
 236 Resources
 237 ---------
 238 ADB - The Untold Story: Space Aliens Ate My Mouse
 239     http://developer.apple.com/legacy/mac/library/#technotes/hw/hw_01.html
 240 Apple IIgs Hardware Reference Second Edition [p80(Chapter6 p121)]
 241     ftp://ftp.apple.asimov.net/pub/apple_II/documentation/Apple%20IIgs%20Hardware%20Reference.pdf
 242 ADB Keycode
 243     http://72.0.193.250/Documentation/macppc/adbkeycodes/
 244     http://m0115.web.fc2.com/m0115.jpg
 245     [Inside Macintosh volume V, pages 191-192]
 246 ADB Signaling
 247     http://kbdbabel.sourceforge.net/doc/kbd_signaling_pcxt_ps2_adb.pdf
 248 ADB Overview & History
 249     http://en.wikipedia.org/wiki/Apple_Desktop_Bus
 250 Microchip Application Note: ADB device(with code for PIC16C)
 251     http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011062
 252 AVR ATtiny2131 ADB to PS/2 converter(Japanese)
 253     http://hp.vector.co.jp/authors/VA000177/html/KeyBoardA5DEA5CBA5A2II.html
 254
 255
 256 Pinouts
 257 -------
 258     ADB female socket from the front:
 259     __________
 260     |        | <--- top
 261     | 4o  o3 |
 262     |2o    o1|
 263     |   ==   |
 264     |________| <--- bottom
 265       |    |   <--- 4pins
 266
 267
 268     ADB female socket from bottom:
 269
 270     ========== <--- front
 271     |        |
 272     |        |
 273     |2o    o1|
 274     |4o    o3|
 275     ---------- <--- back
 276
 277     1: Data
 278     2: Power SW(low when press Power key)
 279     3: Vcc(5V)
 280     4: GND
 281
 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
 385 Keyboard LEDs & state of keys(Register2)
 386     This register hold current state of three LEDs and nine keys.
 387     The state of LEDs can be changed by sending Listen command.
 388
 389     1514 . . . . . . 7 6 5 . 3 2 1 0
 390      | | | | | | | | | | | | | | | +-   LED1(NumLock)
 391      | | | | | | | | | | | | | | +---   LED2(CapsLock)
 392      | | | | | | | | | | | | | +-----   LED3(ScrollLock)
 393      | | | | | | | | | | +-+-+-------   Reserved
 394      | | | | | | | | | +-------------   ScrollLock
 395      | | | | | | | | +---------------   NumLock
 396      | | | | | | | +-----------------   Apple/Command
 397      | | | | | | +-------------------   Option
 398      | | | | | +---------------------   Shift
 399      | | | | +-----------------------   Control
 400      | | | +-------------------------   Reset/Power
 401      | | +---------------------------   CapsLock
 402      | +-----------------------------   Delete
 403      +-------------------------------   Reserved
 404
 405 END_OF_ADB
 406 */