Notes on SmithBug at 0xF000

• SmithBug is a variant of MIKBUG
  • Updated by Herb Johnson to add S Record loader
• 60KB SRAM variant
  • Supports much smaller SRAM sizes but requires scratchpad SRAM if ther is less than 60KB of SRAM
    • Scratchpad RAM has to be at 0xEF00-0xEFFF (minimum 256 bytes)

SmithBug Memory Map

• 0x0000-0x7FFF - 32KB Internal SRAM
• 0XEC00-0xEFFF - 1KB Internal SRAM (SCRATCHPAD SRAM USED BY MIKBUG)
• 0xFC18-0xFC19 - VDU (serSelect J3 JUMPER REMOVED)
• 0xFC28-0xFC19 - ACIA (serSelect J3 JUMPER installed)
• 0xFC30-0xFC3F - Front Panel
• 0xF000-0xFFFF - MIKBUG (Actually SMITHBUG) ROM

Hardware

• Tested/runs on all MultiComp based designs
  • SRAM accesses run at 25 MHz on Internal SRAM
  • Different FPGAs can support more of less internal SRAM
    • EP2C5 FPGA supports 3KB internal SRAM
    • EP4CE15 FPGA supports 32KB internal SRAM
    • Cyclone V FPGA supports 60KB internal SRAM
  • External SRAM works on all MultiComp based designs and supports 60KB SRAM
    • SRAM accesses run at 16.6 MHz on External SRAM

Commands

MIKBUG Commands

Build Instructions

• Creates .hex file load load in Quartus II

..\a68 DGG_MIKBUG.ASM -l DGG_MIKBUG.LST -s DGG_MIKBUG.s
..\srec_cat DGG_MIKBUG.s -offset - -minimum-addr DGG_MIKBUG.s -o DGG_MIKBUG.hex -Intel