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Introduction

  


LOOKING AT THE PLUG
        -------------------------------
 PIN 1->| o  o  o | o  o  o | o  o  o |
        \_____________________________/
    

1. DATA
2. COMMAND
3. N/C (9 Volts unused)
4. GND
5. VCC
6. ATT
7. CLOCK
8. N/C
9. ACK

DATA

Signal from Controller to PSX.
This signal is an 8 bit serial transmission synchronous to the falling edge of clock (That is both the incoming and outgoing signals change on a high to low transition of clock. All the reading of signals is done on the leading edge to allow settling time.)

COMMAND

Signal from PSX to Controller.
This signal is the counter part of DATA. It is again an 8 bit serial transmission on the falling edge of clock.

VCC

VCC can vary from 5V down to 3V and the official SONY Controllers will still operate.

ATT

ATT is used to get the attention of the controller.
This signal will go low for the duration of a transmission. I have also seen this pin called Select, DTR and Command.

CLOCK

Signal from PSX to Controller.
Used to keep units in sync.

ACK

Acknowledge signal from Controller to PSX.
This signal should go low for at least one clock period after each 8 bits are sent and ATT is still held low. If the ACK signal does not go low within about 60 us the PSX will then start interogating other devices.

It should also be noted that this is a bus of sorts. This means that the wires are all tied together (except select which is seperate for each device). For the CLK, ATT, and CMD pins this does not matter as the PSX is always the originator. The DATA and ACK pins however can be driven from any one of four devices. To avoid contentions on these lines they are open collectors and can only be driven low.

The PSX Controller Signals

              |BIT 0|BIT 1|BIT 2|BIT 3|BIT 4|BIT 5|BIT 6|BIT 7|
    CLOCK -----___---___---___---___---___---___---___---___-----------

    DATA  -----000000111111222222333333444444555555666666777777--------
                  *     *     *     *     *     *     *     *
    CMND  -----000000111111222222333333444444555555666666777777--------

    ACK   ----------------------------------------------------------__-
    

The logic level on the data lines is changed by the transmitting device on the falling edge of clock. This is then read by the receiving device on the leading edge (at the points marked *) allowing time for the signal to settle. After each COMMAND is recieved by a selected controller, that controller needs to pull ACK low for at least one clock tick. If a selected controller does not ACK the PSX will assume that there is no controller present.

When the PSX wants to read information from a controller it pulls that devices ATT line low and issues a start command (0x01). The Controller Will then reply with its ID (0x41=Digital, 0x23=NegCon, 0x73=Analogue Red LED, 0x53=Analogue Green LED). At the same time as the controller is sending this ID byte the PSX is transmitting 0x42 to request the data. Following this the COMMAND line goes idle and the controller transmits 0x5A to say "here comes the data".

    
    ATT    -______________________________________________________________
              |   Byte 1     |    |   Byte 2     |    |   Byte 3     |
    CLOCK  ---_-_-_-_-_-_-_-_-----_-_-_-_-_-_-_-_-----_-_-_-_-_-_-_-_-----
                   0xFF                0x41                0x5A 
    DATA   -------------------------__________--__----__--__----__--__----
                   0x01                0x42
    CMND   -----_____________-----__--________--__------------------------

    ACK    --------------------__-------------------__-----------------__-
    

After this command initiation proccess the controller then sends all its data bytes (in the case of a digital controller there is only two). After the last byte is sent ATT will go high and the controller does not need to ACK.

    
    ATT    _______________________________________-------
              |   Byte 4     |    |   Byte 5     |  
    CLOCK  ---_-_-_-_-_-_-_-_-----_-_-_-_-_-_-_-_--------

    DATA   ---D0D1D2D3D4D5D6D7----E0E1E2E3E4E5E6E7-------

    CMND   ----------------------------------------------
                                                    ***
    ACK    --------------------__------------------------

    NOTE: No ACK.
    

The PSX Controller Data

    Standard Digital Pad

    BYTE    CMND    DATA

     01     0x01    idle
     02     0x42    0x41
     03     idle    0x5A    Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
     04     idle    data    SLCT           STRT UP   RGHT DOWN LEFT
     05     idle    data    L2   R2    L1  R1   /\   O    X    []
   
    All Buttons active low.
    

    Analogue Controller in Red Mode

    BYTE    CMND    DATA

     01     0x01    idle
     02     0x42    0x73
     03     idle    0x5A    Bit0 Bit1 Bit2 Bit3 Bit4 Bit5 Bit6 Bit7
     04     idle    data    SLCT JOYR JOYL STRT UP   RGHT DOWN LEFT
     05     idle    data    L2   R2   L1   R1   /\   O    X    []
     06     idle    data    Right Joy 0x00 = Left  0xFF = Right
     07     idle    data    Right Joy 0x00 = Up    0xFF = Down
     08     idle    data    Left Joy  0x00 = Left  0xFF = Right
     09     idle    data    Left Joy  0x00 = Up    0xFF = Down

    All Buttons active low.
    

• Electronic schem :
• Picture of the board :
• Wyntypon : psx.wt3
  Gif : psx.gif