Gadget:Gen-X

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Revision as of 17:28, 27 June 2023 by Gadget (talk | contribs)
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Getting Started

  • Both displays show logos, but only display B is responsive.

Startup

  • On hard-reset, the FPGA copies the first 64k of flash to $0.
  • Post-upload reset leaves that block alone, so you can upload code there.

Documentation

  • The Gen-X on the 68k side appears to be an A2560K; preliminary documentation is Here.
  • The Gen-X on the 68k side appears to be an FMX.

Memory

  • MOVE16 presently only works with the SRAM in the first 4MB.
    • This basically means you can't cache anything anywhere else.
    • TODO: test burst mode from the flash (ie can cache and/or keep MMU tables here?)
  • Stef says to avoid using the DRAM for now.

I/O (68k)

  • Power and SD Card LED control bits at GAVIN:0000 (feca) don't appear to work.
  • I can't seem to get the LFSR to work.
  • The I/O space should be marked as serialized/no-cache (defaults to unserialized -- reads can get ahead of writes).

vasm

  • The 68040 MOVEC cache and MMU control registers are there, but typically without the last letter (R for Register).