Dreamcast G2 bus pinout

The original article, written by jj1odm, is available at http://jj1odm.sizious.com/

@Dreamcast

Published in 

Dreamcast

 · 6 years ago

 
[G2 bus 50pin] 
  
 1 : +5V 
 2 : +5V 
 3 : +5V 
 4 : +5V 
 5 : /MODEMCS * modem enable       {output} (modem / lan adaptor [HIT-0300] area enable) 
 6 : /IRQA    * interrupt request A {input} (used modem unit / lan adapter [HIT-0300]) 
 7 : ??? 
 8 : ??? 
 9 : ??? 
10 : GND 
11 : GND 
12 : GND 
13 : /IRQB    * interrupt request B {input} (used BBA [HIT-0400]) 
14 : /LBE /WR * lower byte enable  {output} (direction / lower byte enable / write enable (when active /MODEMCS)) 
15 : ??? 
16 : /UBE /RD * upper byte enable  {output} (upper byte enable / read enable (when active /MODEMCS)) 
17 : +3.3V 
18 : +3.3V 
19 : +3.3V 
20 : /BTB     * bus termination B   {input} (access time control / burst transfer) 
21 : /AEN     * address enable     {output} (address enable / bus cycle start) 
22 : /BTA     * bus termination A   {input} (access time control / burst transfer) 
23 : GND 
24 : GND 
25 : AD15     * 
 .    .       * AD[15:0]     {output/input} (address / data multiplexed 16bit bus) 
 .    .       *  25pin to 40pin             (AD[15:8] 8 bit address bus / AD[7:0] 8 bit data bus (when active /MODEMCS)) 
40 : AD0      * 
41 : GND      *                             (guard GND of system clock) 
42 : GND      *                             (guard GND of system clock) 
43 : CLK      * system clock       {output} (25MHz) 
44 : GND 
45 : GND 
46 : /RESET   * system reset       {output} 
47 : GND 
48 : GND 
49 : ??? 
50 : ??? 

thank's bITmASTER and Dan Potter