315-5356

Found on...

• SEGA Mega-Tech Motherboard

Equations

Name     	315-5356;
PartNo   	;
Date     	;
Revision 	;
Designer 	Porchy;
Company  	;
Assembly 	;
Location 	;
Device   	g16v8;

/* Dedicated input pins */

pin 1   = A15;    /* Input */
pin 2   = A14;    /* Input */
pin 3   = A13;    /* Input */
pin 4   = A12;    /* Input */
pin 5   = A11;    /* Input */
pin 6   = A10;    /* Input */
pin 7   = A19;    /* Input */
pin 8   = RD;     /* Input */
pin 9   = WR;     /* Input */
pin 11  = RFSH;   /* Input */

/* Programmable output pins */

pin 12  = WR-OUT; /* Combinatorial output */
pin 13  = MREQ;   /* Input */
pin 14  = NMI;    /* Fixed high output */
pin 15  = A0;     /* Unused input */
pin 16  = NC;     /* Combinatorial output */
pin 17  = RXRDY;  /* Unused input */
pin 18  = RESET;  /* Unused input */
pin 19  = RD-OUT; /* Combinatorial output */

/* Output equations */

!RD-OUT = !A15    &  A14    &  A13    &  A12    &  A11    & !A10    & !A19    & !RD     &  RFSH   & !MREQ;
!NC     = !A15    &  A14    &  A13    &  A12    &  A11    & !A10    &  A19    &  RFSH   & !MREQ;
 NMI    = 'b'1;
!WR-OUT = !A15    &  A14    &  A13    &  A12    &  A11    & !A10    & !A19    & !WR     &  RFSH   & !MREQ;

/* End */

Notes

• Read and write access to the uPD71051 chip is at address $7800
• Pin 16 is not connected on the PCB but has equations mapped to address $7C00 which is appears to be unused in the code