27 Apr
2013
27 Apr
'13
5:02 p.m.
On Saturday, April 27, 2013 14:41:17 ben wrote:
Someone posting to this list is over halfway there :-)
On 4/27/2013 1:05 PM, David Riley wrote:
Current hardware tends to stop at 3.3V. There is nothing stopping you
from
adding your own level convertors to raise that to 5V. Might be a bit difficult
to make all the electrical bits conform to the original specs. Not in any way
impossible, though.
Conversely, though, there are plenty of things
that a CPU is much more
suitable for, specifically most things that are highly sequential. You
wouldn't want to make a web server on an FPGA, for example, because you
would need to make lots of complex state machines that would be really
hard to debug. Fortunately, it's usually pretty easy to just bolt on
a microcontroller (or build one in FPGA logic, because a CPU is really
just a specialized state machine with some logic and registers bolted
on). Both Xilinx and Altera have soft-core CPUs that are free to use
and toolchains for them that aren't COMPLETE nightmares.
I agree with that. I like the wall of paper docs, rather than
click on video to show how to <blah blah blah>. My only real gripe
with the modern logic, is to my knowledge the I/O tat is NOT 5 volt
tolerant. I would like to use the 40 pin headers for IDE
interfacing or some other
'classic' interface. That might be a good project for the DEx boards
a 5 volt interface and breadboard. Even if I can't use it for my
hardware, I still have a dirt cheap PDP-11.
Yep. You can have an 11/94 for the
price of a de0-nano, some wires, an r232
level shifter and an sd card. If you try hard enough, you can keep that under
$100.
And, you could also add the hardware you're thinking of interfacing to, inside
the FPGA instead. In many cases, implementing the logic in the FPGA itself is
not really that much harder than implementing the interface to the real
hardware. Consider how I did the rs232 and disk controllers - somewhat
complex, but probably easier than interfacing to the real hardware. Does the
job, though.
- Dave
Ben.
PS. I need to dig on the web to if there is a PDP-10 done yet.