Individual Computers Catweasel

These controllers are designed to allow more recent computers, such as PCs, to access a wide variety of older or non-native disk formats using standard floppy drives.

Many other computers, particularly ones from Commodore and early ones from Apple, write disks in formats which cannot be encoded or decoded by the 765A, even though the drive mechanisms are more or less identical to ones used on PCs.

[3] A version of the Catweasel controller was developed for use in a standard PC ISA slot as a means of reading custom non-PC floppy formats from MS-DOS.

In addition to the low-level access granted to floppy drives, it has a socket for a Commodore 64 SID sound chip, a port for an Amiga 2000 keyboard, and two 9-pin digital joysticks (Atari 2600 de facto standard).

[citation needed] This version of the Catweasel makes heavy use of reconfigurable logic in the form of an Altera ACEX EP1K30TC144-3N[9] FPGA chip, as well as an AMD MACH110 PLD and a PCI interface IC.

The Mk4/Mk4+ driver uploads the FPGA microcode on start, which makes easy updates possible without having to replace hardware.