Am 02.01.2014 20:41, schrieb Al Kossow:
On 1/2/14 10:42 AM, Peter C. Wallace wrote:
The Zynq is just way overpriced for what it is.
Unless you need high
processor <=> FPGA bandwidth, a Spartan6 and a seperate Arm chip with
simple bus interface is 1/2 the price or less.
Peter Wallace
Mesa Electronics
What is your preferred Arm processor and FPGA interface method these days?
I'm not Peter, but here's an answer...
I used an FPGA board from ztex.de for recovering data from a Diablo 44
drive bit by bit and for simulating a DG disk subsystem. All I had to
add was the DG bus interface with 3.3V logic on the FPGA side, which can
also be connected to the D44 with an adapter cable. A simple 2 layer PCB.
For the data recovery project I used the on-board CY68013 USB interface
to a PC. The PC could be replaced by one of the small ARM based boards.
The CY68013 has plenty of bandwith for my applications. It wasn't even
necessary to go deep into USB as there are lots of examples for this chip.
Opal Kelly has nice boards up to USB 3.0 and PCIe and a nice API with
HDL examples which require even less USB or PCIe knowledge.
For such projects, which are not mass production and don't depend on a
certain form factor, I'd never develop an FPGA/processor platform by myself.
For the disk emulator I used a stand-alone solution with a soft CPU,
first the Gaisler Leon-3, later a MIPS from a colleague, programmed in
plain C. I planned to run RTEMS, but found the whole thing bloated for
my application. I will re-develop the emulator using the J1 Forth CPU,
which is very nice for small control applications. Just a small FPGA, an
SD Card and the DG bus interface. No high performance CPU, no OS, no
external RAM. I always come to a point where I think a high performance
CPU could run simh, a large FPGA could swallow all the vintage hardware.
For just solving the problem it's fine, but it somehow hurts my eyes.
Andre