Portable Amiga anyone??

[mikej]

I have mailed him, but no response yet...

Hi Picman,
I got your email, but I haven't had a chance to reply yet.
If you look on http://www.fpgaarcade.com and scroll down a bit you will see the hi-res touch LCD daughter board for the Replay board, which is a prototype for a portable machine.

Work is progressing on a 68030 core well, this will be released with a new Amiga core for the Replay board as soon as possible.

I design ASICs / boards for a living and have to say doing it on 4 layers is almost impossible to do while keeping good power and ground planes needed for good signal integrity, really important for the high speed video and memory busses. You could do it if you go to 4 thou traces but then the PCB cost goes higher than a cheap 6 layer board. I use Mentor PCB tools for the design.

Designing the PCB is by far the easiest bit of the work. There is a lot of software design in in the embedded controller and design work in the video and memory subsystems. It looks like not much has happened since I got the first board back in the summer, but it's been a long slog to get the rest of the system written.

The other big headache is to get these boards produced at a good price you have to buy in bulk and from the suppliers directly. I am lucky enough to go to China a lot, so I have been talking and buying a lot of components in Shenzhen. I have quite a collection of bits now

So, I think it is great if you want to work on this, but don't underestimate the amount of work it takes to get it up and running.

I'll mail you privately as well.
Best,
Mike

[mikej]

Actually, it is a very nice system. What I don't like is the additional processor for boot & disk.
Prefer the version on the Altera de2 boards, where a processor build into the FPGA does the additional load. I think it is a much cleaner design.

I agree, but there are some downsides. You need to configure the FPGA from something initially. You can do this from a serial flash device and then use a processor core in the FPGA to bootstrap the system. The problem with this is that the firmware the core is using is also burned into the flash so it is not easy to bug fix it - not practical in a mass produced design.

The advantage of using the external ARM is it costs about the same as an external flash and it is much easier to re-load the firmware from the SD card should an update be needed. You can also recover easily (on the Replay board at least) from a bricked system using the USB port to re-flash the ARM.

Picman, one thing about your pricing. Don't forget the passive components - on the Replay board the power supplies, resistors, caps and connectors account for more than half the component cost...

/MikeJ

[mikej]

Mumule,
yes you are right, the SPI boot would be an option - but I want(ed) the option of moving to a spartan6/altera device in the future so didn't want to tie myself in to much.

There is a quite a bit of software in the ARM to boot up and run the OSD etc, and for things like hard disk support you want that running at the same time as the host processor.
I like the fact I can run this independently of whatever processor is running in the FPGA.

Cheers,
Mike

[mikej]

"Just put in the spartan6 already on your board, saves you a lot of trouble changing it later anyway."

ha, tempting. I already changed from spartan3 to 3e, and if I start the change to spartan6 they will have brought out spartan7 before I finish the damn thing
/Mike