1.2 KiB
A FPGA on a NuBus card...
Goal
The goal of this repository is to be able to interface a modern (2021 era) FPGA with a NuBus host, specifically Apple's Macintosh II and Macintosh Quadra.
Current status
First prototype is working in a Quadra 650. It implements a single-screen-resolution, windowboxed multi-resolution, depth-switchable (1/2/4/8/16/32 bits) framebuffer over DVI-in-HDMI-connector (will work with any HDMI-compliant monitor). The framebuffer can be used as secondary/primary/only framebuffer in the machine running OS8.1. Qemu tests indicate this should work with 7.1 & 7.5/7.6 as well.
Some basic acceleration now exists for 8/16/32 bits, doing rectangle screen-to-screen blits and pattern rectangle fills. 1/2/4 bits also has some acceleration, ut only for byte-aligned cases.
There's also a basic RAM Disk using the 248 MiB of SDRAM not used by the framebuffer. So far this is by 32-bits accesses from the host; DMA using 1x block mode is still TBD.