菜鸟紧急求助！！！

各位前辈，我是一名菜鸟，毕设选了比较难的驱动程序设计，现在的情形有点进退两难。本来我认为写手柄驱动应简单一些（其他的有的没硬件，有的没有各种端口信息），可现在我感到越来越困难了。有哪位好心人能就下面的资料给提点建议或给点帮助（有原程序最好），菜鸟会不盛感激！！！！


1. pin assign

memory card
        _______________________________
       |                               |
       |  O  O  O    O  O  O    O  O   |    (front view PSX)
       |_______________________________|

    pin   9  7  6    5  4  3    2  1

    PS   PAD connecter
=============================
|  O  O  O| O  O  O| O  O  O |    (front view PSX)
\\________|________|_________/

    pin    9  8  7  6  5  4  3  2  1

Pin signal  dir active description
--------------------------------------------------------------------
1. dat      in   pos  data from pad or memory-card
2. cmd      out  pos  command data to pad or memory-card
3. +7V      --   --   +7.6V power source for CD-ROM drive
4. gnd      --   --
5. +3V      --   --   +3.6V power source for system
6. sel      out  neg  select pad or memory-card
7. clk      out  --   data shift clock
8.   --     --   --   N.A.
9. ack      in   neg  acknowladge signal from pad or memory-card
--------------------------------------------------------------------

*1) direction(in/out) is based from PSX

*2) metal edge in pad connecter is connected pin 4 and sheald calbe.

*3) signal SEL in PAD1, PAD2 is separated.


2. Comminucation timing chart

  Timing is compatibled in PAD, Memory-card.
  

Overview
      ____                                                              _____
 SEL-     |____________________________________________________________|    
      ______        ____        ____        ____        ____        _________
 CLK        ||||||||    ||||||||    ||||||||    ||||||||    ||||||||        
      _______________________________________________________________________
 CMD       X  01h   XXXX  42h   XXXX  00h   XXXX  00h   XXXX  00h   XXXX    
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    
           _____________________________________________________________    
 DAT  -----XXXXXXXXXXXXX   ID   XXXX   5Ah  XXXX  key1  XXXX  key2  XXXX-----
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~    

 ACK- ---------------|_|---------|_|---------|_|---------|_|-----------------


top command. first comminucation(device check?)
      ____                                                                  
 SEL-     |__________________________________________________________________
      ______   _   _   _   _   _   _   _   __________________   _   _   _   _
 CLK        |_| |_| |_| |_| |_| |_| |_| |_|                  |_| |_| |_| |_|
      __________                                                  ___        
 CMD            |________________________________________________|   |_______
                                                             ____            
 DAT  -----XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX    |___________
                                                                            
 ACK- ----------------------------------------------|___|--------------------

X = none, - = Hi-Z

    0x81 is memory-card, 0x01 is standard-pad at top command.

    serial data transfer is LSB-First format.

    data is down edged output, PSX is read at up edge in shift clock.

    PSX expects No-connection if not returned Acknoledge less than 100 usec.

    clock pluse is 250KHz.

    no need Acknoledge at last data.

    Acknoledge signal width is more than 2 usec.

    time is 16msec between SEL from previous SEL.

    SEL- for memory card in PAD access.


3. example schematic chart of interface(5 volte to 3.3 volte convertion)

example in PAD

 PAD       PS system
 /|  P  R,200ohm P=pullup(no need?)
PAD SEL   ---- O<  |--+--\\/\\/\\/-- PS SEL-
 \\|
HC14
 /|  P  R,200ohm
PAD CMD-  ---- O<  |--+--\\/\\/\\/-- PS CMD
 \\|
HC14
 /|  P  R,200ohm
PAD CLK-  ---- O<  |--+--\\/\\/\\/-- PS CLK
 \\|
HC14
PAD DAT   _________
 |
|\\O
   ----| > ------------- PS DAT
  | |/
  V HC125
PAD ACK-  _________
  |
|\\O
   ----| > ------------- PS ACK-
  | |/
  V   HC125


example in PSX

PSX  PAD

   SEL-  _________
  |
|\\O  P P=pullup
   ----| >--+---------- PAD SEL-
  | |/
  V HC125
   CLK   _________
  |
|\\O  P
   ----| >--+---------- PAD CLK
  | |/
  V   HC125
   CMD   _________
  |
|\\O  P
   ----| >--+---------- PAD CMD
  | |/
  V   HC125

/|  P  R,200ohm
   DAT-  ----O< |--+--\\/\\/\\/-- PAD DAT
\\|
HC14

/|  P  R,200ohm
   ACK-  ----O< |--+--\\/\\/\\/-- PAD ACK-
\\|
HC14


4. communication format in PAD

  must be start translation, after command expected \"0x01h\" from PS-system.
  PAD has 1-byte ID. pad is send a 2 byte of key-code + extend code after
PAD ID \'Z\'(5Ah).

normal pad    timing flow ->

10000000 01000010 01011010 01234567 01234567
|--------|--------|--------|--------|--------|
 CMD |   01h  |  42h   |   00h  |   00h  |   00h  |
|--------|--------|--------|--------|--------|
         xxxxxxxx 10000010 10100101 01234567 01234567
|--------|--------|--------|--------|--------|
 DAT |  ----  |  41h   |   5ah  |  SW.1  |  SW.2  |
|--------|--------|--------|--------|--------|
 device ID   \'Z\'

data contents of normal PAD.(push low)
+----------+----+----+----+----+----+----+----+----+
|  byte    | b7 | b6 | b5 | b4 | b3 | b2 | b1 | b0 |
+==========+====+====+====+====+====+====+====+====+
|   +0     |               -----                   |  N.A.
+----------+---------------------------------------+
|   +1     |                0x41                   | \'A\'
+----------+---------------------------------------+
|   +2     |                0x5a                   | \'Z\'
+----------+----+----+----+----+----+----+----+----+
|   +3     |LEFT|DOWN|RGHT| UP | STA|  1 |  1 | SEL|
+----------+----+----+----+----+----+----+----+----+
|   +4     | [] | X  | O  | /\\ | R1 | L1 | R2 | L2 |
+----------+----+----+----+----+----+----+----+----+

本来有一幅手柄和并口的接线图，我不知道怎样贴，只好用文字了。
D0----cmd
D1----sel
D2----clk
(D3,
 D4,
 D5,--二极管--+3.6V
 D6,
D7)
ACK---data
PE----ack
GND---GND
左边是并口线，右边是手柄线。