Editing Ultimate 64 Motherboard (section)

== Key features ==
* '''All-FPGA core''' – replaces every major MOS device, eliminating ageing silicon while preserving ~99.9 % software and demo compatibility, including tricky “cycle-tricks” and bad-line conditions.
* '''Integrated 1541-Ultimate II+''' – IEC drive emulation (D64/G64/TAP/T64/PRG), freezer, action-replay, REU (RAM Expansion Unit) up to 16 MB and GeoRAM, plus KERNAL cartridge injection and SID player.
* '''Digital video & audio''' – lag-free HDMI output at 720 p with optional scan-lines, border cropping and PAL/NTSC switching on-the-fly; 48 kHz 16-bit stereo mixes real SIDs with FPGA soft-SID.
* '''Dual-SID support''' – two physical sockets with automatic 9 V/12 V rail sensing; FPGA mixer allows true stereo separation and independent filter curves per chip.
* '''Network stack''' – 100 Mbit LAN for disk-image mounting over FTP/TFTP, firmware updates, IEC drive sharing and real-time clock synchronisation via NTP.
* '''Ultimate Command Interface''' – JSON‐RPC over USB or Ethernet for headless control and integration with PC front-ends.
* '''Silent & cool''' – the board draws ≈ 1.1 A @ 5 V; an optional 40 mm fan header is provided but rarely needed.