converter/ibm4704_usb/4704.txt

   1 4704 Keyboard
   2 =============
   3 Keyboard Models:
   4     Model 100 6019273 50-key (grid layout)
   5     Model 200 6019284 62-key Alpha(60% layout)
   6     Model 300 6019303 77-key Expanded Alpha
   7     Model 400 6020218 107-key Full key
   8
   9 Resourse
  10 --------
  11 The IBM 4704: lots of pictures and info
  12 http://kishy.dyndns.org/?p=648#more-648
  13
  14 Brochure:
  15 http://ed-thelen.org/comp-hist/IBM-ProdAnn/4700.pdf
  16
  17
  18
  19
  20 4704 Keyboard Protocol
  21 ======================
  22 On powering up the keyboard sends keyboard id; A3h for 6019284(62-key), for example.
  23 After that firmware enters FC command mode and waits for parameter data from host
  24 so that it doesn't send any scancode until you send 'FF'(End of FC command).
  25
  26
  27 Keyboard to Host
  28 ----------------
  29 Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
  30
  31             ____      __   __   __   __   __   __   __   __   __   ________
  32     Clock       \____/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
  33                  ____ ____ ____ ____ ____ ____ ____ ____ ____ ____
  34     Data    ____/    X____X____X____X____X____X____X____X____X____X________
  35                 Start   0    1    2    3    4    5    6    7    P  Stop
  36
  37 Start bit:  can be long as 300-350us.
  38 Inhibit:    Pull Data line down to inhibit keyboard to send.
  39 Timing:     Host reads bit while Clock is hi.
  40 Stop bit:   Keyboard pulls down Data line to lo after 9th clock.
  41
  42
  43
  44 Host to Keyboard
  45 ----------------
  46 Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
  47
  48             ____        __   __   __   __   __   __   __   __   __   ________
  49     Clock       \______/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/  \_/
  50                 ^   ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ___
  51     Data    ____|__/    X____X____X____X____X____X____X____X____X____X   \___
  52                 |  Start   0    1    2    3    4    5    6    7    P   Stop
  53                 Request by host
  54
  55 Start bit:  can be long as 300-350us.
  56 Request:    Host pulls Clock line down to request to send a command.
  57 Timing:     After Request keyboard pull up Data and down Clock line to low for start bit.
  58             After request host release Clock line once Data line becomes hi.
  59             Host wirtes a bit while Clock is hi and Keyboard reads while low.
  60 Stop bit:   Host releases or pulls up Data line to hi after 9th clock and waits for keybaord pull down the line to lo.
  61
  62
  63
  64 Scancodes
  65 ---------
  66 Keyboard doesn't send Break code for all keys except for Alt by default.
  67
  68     6019284 62-key:
  69     ,-----------------------------------------------------------.
  70     |  `|  1|  2|  3|  4|  5|  6|  7|  8|  9|  0|  -|  =|???|BS |
  71     |-----------------------------------------------------------|
  72     |Tab  |  Q|  W|  E|  R|  T|  Y|  U|  I|  O|  P| ￠|  \|  PD2|
  73     |-----------------------------------------------------------|
  74     |Ctrl  |  A|  S|  D|  F|  G|  H|  J|  K|  L|  ;|  '| {}| PD3|
  75     |-----------------------------------------------------------|
  76     |Shif| <>|  Z|  X|  C|  V|  B|  N|  M|  ,|  ,|  /|???|Shift |
  77     |-----------------------------------------------------------|
  78     |Reset|blk|Alt  |         Space             |Alt  |blk|Enter|
  79     `-----------------------------------------------------------'
  80     +----------+---------------------+----------+----------+
  81     |`       00|PD1     04|Caps    20|LShift  30|Reset   31|
  82     |1       18|q       05|a       21|<>      3E|Rblank  41|
  83     |2       19|w       06|s       22|z       32|Alt     3F|
  84     |3       1A|e       13|d       23|x       33|Space   40|
  85     |4       10|r       14|f       24|c       34|Alt     3F|
  86     |5       11|t       15|g       25|v       35|Lblank  42|
  87     |6       12|y       16|h       26|b       36|Enter   2F|
  88     |7       08|u       17|j       27|n       37|          |
  89     |8       09|i       01|k       28|m       38|          |
  90     |9       0A|o       02|l       29|,       39|          |
  91     |0       0F|p       03|;       2A|.       3A|          |
  92     |-       1F|￠      1B|'       2B|/       3B|          |
  93     |=       0D|\       1C|{}      2C|???     3C|          |
  94     |???     0C|PD2     1D|PD3     2D|RShift  3D|          |
  95     |BS      0E|          |          |          |          |
  96     +----------+---------------------+----------+----------+
  97     Bit7 is 'press flag' which set 1 on press and 0 on release when break code is enabled.
  98
  99 NOTE: When break code is enabled the key sends scancode with setting 7th bit on press
 100 and without it on release. That is, '`' sends 80h on press and 00h on release.
 101
 102
 103 keyboard command
 104 ----------------
 105     FF  Soft Reset(0008h)
 106     FE  Resend(00e8h)
 107     FD  Buzzer stop?(00edh)
 108     FC  Set Key flag(00f6h)
 109     FB  Soft Reset(0008h)
 110     FA  Reset(0000h)
 111
 112
 113 Keyboard response
 114 -----------------
 115     FF  Not exist. [Outgoing buffer cannot have FFh(00h in fact)]
 116     FE  Overflow(key event/receive data)        at 00c5h, 0346h
 117     FE  Memory test error                       at 0224h
 118     FD  Command out of bound                    at 00d8h
 119         Key out of bound
 120     7E  Read/Parity error in receive from host  at 00bch
 121
 122
 123 Set Key flag command(FC)
 124 ------------------------
 125 After 'Power on Reset' firmware enters this command mode and waits for data from host,
 126 so that you don't need to send 'FC' and it doesn't send any scancode until you send 'FF'.
 127
 128 Data sent from host:
 129
 130     bit: 7   6 ... 0
 131          en  |     |
 132          |   `-----`--- scan code
 133          `------------- enable bit(0: enable repeat, 1: enable break)
 134
 135     00-77   Enable repeat(78-7F: invalid scancode)
 136     80-F7   Enable break(F8-FF: invalid scancode)
 137     FE      Resend(011ah) no need to use
 138     FF      End(0114h) exits FC command mode.
 139
 140 Response from keyboard:
 141     FD      Out of bound - Invalid scancode
 142
 143 Examples:
 144     To enable break code of all keys.
 145
 146     FC 80 81 ... F7 FF
 147