Hard disk emulation support

After several months of inactivity (mostly due to health problems and personal issues), a new version of zeST is finally available!

It features support for hard disk drive emulation. Only one drive is emulated for now, but it would be rather easy to implement more.

On the technical side, the most difficult task was to implement a generic ACSI peripheral correctly and have it talk with the ST’s DMA controller, without disturbing the proper behaviour of the floppy controller, which is also accessed by the DMA chip. This involved an important work of internal redesign, which should simplify further important modifications.

That generic ACSI peripheral basically is an interface to a software driver that runs on the Zynq’s Arm CPU. The only parts implemented in hardware are the mechanisms to send commands (read or write sectors, get drive information etc.) to the peripheral, and data transfers via DMA. This way, it should be easy to implement different hardware using the same interface, and only performing changes on the Arm software level.

Download links and ACSI setup instructions are available on the Getting started page.

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