/* GAL 3 (XRAM - 512 KB Memory Expansion) for SYS-Check V2.2      08/2015 by tfhh   */

CHIP	XRAM	GAL16V8  COMPLEX_MODE

A14   A15   RW   PHI2  PHI2S  PB2     PB3   PB4   ENX   GND
EMEM  XRAM  PB7  RA18  XCLK   EXTSEL  D301  RA14  RA15  VCC

/XCLK = /D301 * /ENX * EMEM;                                    /* Generate clock signal for PB1...PB6 latch only in XRAM mode */

RA14 = A14 * /EMEM                                              /* SRAM A14 in Sys-Check mode */
     + PB2 * EMEM * /ENX;                                       /* SRAM A14 in XRAM mode */

RA15 = A15 * /EMEM                                              /* SRAM A15 in Sys-Check mode */
     + PB3 * EMEM * /ENX;                                       /* SRAM A15 in XRAM mode */

RA18 = /EMEM * ENX
     + PB7 * EMEM * /ENX;

/XRAM = A14 * /A15 * /PB4 * EMEM * /ENX;                        /* ChipSelect XRAM mode r/w access $4000-$7FFF */

EXTSEL = VCC;


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