I’m still working on development of an FPGA-based disk controller card for the Apple II – Yellowstone. Over the past couple of months, I spent a long while analyzing the design of the UDC disk controller. The UDC supports all…
Today I’m excited to introduce a major new feature update for the BMOW Floppy Emu Disk Emulator. The latest firmware for use with Apple II computers adds the three most frequently requested new features: writeable WOZ and NIB disk images,…
In an earlier blog post, I was lamenting how one-ninth of an FPGA block RAM was wasted when storing 8-bit ROM data, because there’s no simple way to make use of the 9th parity bit in each word of a…
This FPGA-based disk controller project is going to need every byte of on-chip memory that I can scrounge up. The datasheet says my Lattice MachXO2-1200 has 64 Kbits of embedded RAM (EBR). See the shaded column in the table above.…
I’m still working on development of a disk controller card for the Apple II. As part of that effort, I’m still trying to understand the design of the UDC disk controller. My hope is to combine what I learn about…
I’m developing an Apple II disk controller that’s based on the UDC disk controller design. The original UDC card had 8K of ROM and 2K of RAM, so it needs 10K of combined memory. The FPGA device I’m using for…
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