13 May
2004
13 May
'04
4:35 a.m.
"Peter C. Wallace" wrote:
...
> use the board for a wide range of applications,
resulting in higher
> production volume and lower cost. I know that a list member was
> designing a board like this. I don't know how far he got. But my offer
I'm designing a simple board with a PIC cpu and a CPLD which should be able
to emulate virtually any disk controller (given software).
I have found about 100 of the unibus drivers on the secondary market.
The idea is that the cpld holds a register set which the PIC and unibus
can read/write and the PIC can be a bus master to read/write unibus
memory.
A serial port will allow the firmware in the pic to be updated to
allow one to change controllers.
An IDE interface for a true ide disk or CF card is on other side.
My goal is to start with something simple like an RL02 interface. I may
go on to do something like the UDA50. This is mostly because I have an
RL02 and UDA50 controller.
I'm still on paper, so I may substitue one of the cool philips ARM cpu's
which have built in flash and ram, mostly because I could then write the
emulation code in C. It depends on the speeds I need. I have not done
the unibus hdl code yet, and that will drive the timing of the cpu.
Initially I want the device to be able to run in "stupid ide mode" by
programming the cpld as a pass through and exposing the ide registers
directly on the unibus. This way the device can be useful right away
and gradually get more sophisticated as more software is written.
If I do it right the cpu should be able to reprogram the cpld so
everything can be field programmed.
the real problem is that my day gig keeps getting in the way of my fun :-)
I hope to have a prototype this summer - I'll certainly publish everything
and take orders if anyone wants one :-)
-brad