----------------------------------------------------------------------
Cable
----------------------------------------------------------------------

The XLINK cable is a simple 8-bit parallel transfer cable connecting
the PC Parallel Port to the C64 User port.

       ---------------------------------------------
       PC Parallel Port   |     C64 User Port
       ---------------------------------------------
       GND    (18-25)    <->    GND    (1, 12, A, N)
       D0     (2)        <->    PB0    (C) 
       D1     (3)        <->    PB1    (D) 
       D2     (4)        <->    PB2    (E) 
       D3     (5)        <->    PB3    (F) 
       D4     (6)        <->    PB4    (H) 
       D5     (7)        <->    PB5    (J) 
       D6     (8)        <->    PB6    (K) 
       D7     (9)        <->    PB7    (L) 
       BUSY   (11)       <--    PA2    (M) 
       STROBE (1)        -->    /FLAG2 (B) 

A shielded cable is recommended. The cable shield should be connected
to shield ground on both sides. A 0.1uF capacitor between shield and
ground at the c64 side can also help to reduce noise. Improper
shielding will most likely cause transfer errors.

CAUTION: There is no protection of any kind. The parallel port pins
are directly connected to port B of CIA2. Always power down both the
PC and C64 before inserting/removing the cable. Also turn off the C64
during boot, reboot or shutdown of the PC.

----------------------------------------------------------------------
Optional Reset Circuit
----------------------------------------------------------------------

This small circuit can be used to force a hardware reset of the C64
when the INIT line at the parallel port is pulled low.
                  
 INIT                      +5V                          
  o                         o                                          
  |      ____               |                                  
  o-----|____|--------------o       o RESET                                    
  |      10k                |       |                                      
  |                 ____    |       |                                    
  |            ----|____|---'       |                                       
  |            |    1.5k            |                                   
  |            |                 |  C                        
  |            |                 | /                                       
  |         |  C-----------------|B                                             
  |  ____   | /                  | \                                            
  '-|____|--|B                   |  E                                          
     10k    | \                     |                       
            |  E                    |                                          
               |                    |                                       
               o                    o                                       
              GND                  GND                                      
                                                                              
                                                                               
INIT is pin 16 at the parallel port, RESET is pin 3 at the user port.
GND and +5V can safely be taken from the user port as well.
Use BC547A or equivalent transistors.
