Acorn AEH50 Ethernet II Podule

Register description

IOC address map :
  0000-1fff - ROM (read)
  2000-2fff - IRQ status (read)
              bit 0 - IRQ active
  3000-3fff - Page register (write)
              bits 0-8 - ROM page (not used with default ROM)
              bit 14 - Remote DMA port access direction (1=read, 0=write)
              bit 15 - DP8390 reset (active low)

MEMC address map :
  2000-2fff - Remote DMA transfer port
              Used with both byte and word accesses
  3000-3fff - DP8390 registers
              Arc A2-A5 connected to A0-A3

Notes

ROM contains podule ID and MAC address, but no software.

Acorn's documentation states that the card uses 2x 8kb SRAMs, however the actual podule seems to have 2x 32kb SRAMs on board, for a total of 64kb buffer memory.

DP8390 is the controller used on the PC NE2000 cards. Acorn's Ether2 driver uses functionality not generally used on NE2000 due to compatibility issues with DP8390 clones - notably loopback mode and the remote DMA send packet command.