The RETRO-EP4CE15 card has 1MB of SRAM on the card. The SRAM is in (2) 8KB windows with 64 banks in each window.

I wrote a test routine that writes ramp values to the SRAM and verifies it works.

The test program prints:

S0++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++D

Where:

• S = start
• 0/1 = block number
• + = block good
• X = bad
• D = done

Hit a key at end to avoid resetting the Serial port until done. 

Jumps back to SmithBUG when done.

Takes ~2 secs to run with 25MHz ROM/Internal SRAM and 16.7 MHz for External SRAM.

Assembled using A68 assembler

"..\..\A68 6800 Assembler\a68.exe" XRAMTEST.ASM -l XRAMTEST.LST -s XRAMTEST.SRE

Memory Map

• 0xA000-0xBFFF - 512KB External SRAM
  • 8KB Windows, 64 frames
  • MMU0 provides additional address bit
  • MMU0 initialized to 0
• 0xC000-0xDFFF - 512KB External SRAM
  • 8KB Window, 64 frames
  • MMU2 provides additional address bits
  • MMU2 initialized to 0
• 0xFC30 - MMU0 Latch 6-bits
• 0xFC31 - MMU1 Latch 6-bits