Mico32, how good is it?

I probably will use a full-blown 32-bit CPU in my next project. And I was thinking if I could use the Lattice Mico32 Unfortunately, I haven't had time to get familiar with this CPU yet. I know however that more than a few of you have been playing with it, so I am asking for your impression so far.

I will be very thankful if anyone can answer any of the following questions:

- What do you think of the CPU so far? How does it compare to the alternatives?

- In terms of size and speed, how does it compare to the competition?

- How good is the software support (GCC) and how well designed is the HAL and low-level library connection? How well is the Wishbone interface working in practice?

- If I plan to use a non-Lattice FPGA, would things work as smooth or will development become much more difficult?

- How does the area & speed change across FPGA families and vendors? I remember that Mico8 became noticeably larger when targeting Cyclone and Spartan FPGAs...

- Are any there any technical difficulties against porting Linux to this CPU? (just out of curiosity and completely unrelated to my project)

thank you in advance, burns

Reply to
burn.sir
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The only tricky bit will be the debugger, as that uses the dedicated Lattice JTAG block. Workaround that, and the rest should be no problem at all.

It doesn't have an MMU, so the full blown Linux is out of the question. However, it should be relatively straight forward to port uCLinux.

Cheers, Jon

Reply to
Jon Beniston

Thank you for your answer Jon,

The JTAG problem was expected, and is easy to fix (write your own JTAG block). Regarding the MMU, well, I have heard the MB cannot be modified to include a MMU, is the same true for Mico32?

The reason that I posted my previous questions in the first place was that if you synthesize a Mico32 project with, say, Quartus II you will notice that it cant fit in _any_ Cyclone II devices. The reason is that the lm32_ram block is designed in such way that the Quartus synthesizer cannot infer MK4 blocks...

So my question to the list: has _anyone_ tried this CPU on Altera devices?

regards, burns (still wait> > - If I plan to use a non-Lattice FPGA, would things work as smooth or

Reply to
burn.sir

snipped-for-privacy@gmail.com schrieb:

it works on Xilinx so should also work in A :)

Antti

Reply to
Antti

No surprise there, Mico32 was Originally _designed_ for Xilinx FPGAs.

burns

Antti wrote:

Reply to
burn.sir

snipped-for-privacy@gmail.com schrieb:

hmm. I had a vision that it wasnt directly originated from Lattice ;)

Antti

Reply to
Antti

And how would you know that? (Because it isn't true :-) ).

Cheers, Jon

Reply to
Jon Beniston

You could add an MMU to Mico32. It would probably have to sit on the bus rather than in the pipeline though (unless you want to ripup the pipeline completely). So you have virtually tagged caches etc. You could either use the user defined instructions for updating the TLB, or just memory map them.

Cheers, Jon

Reply to
Jon Beniston

Just one thing, MicroBlaze can of course have a MMU. Wonder what the idea this it's impossible come from?

Göran Bilski

Reply to
Göran Bilski

So Göran,

When will it be ready ;-)

Lattice is already talking about that a MMU is on it's way..

Regards

Finn

"Göran Bilski" skrev i en meddelelse news:ekgq4k$ snipped-for-privacy@cnn.xsj.xilinx.com...

Reply to
Finn S. Nielsen

Even if I know exactly if and when, it's nothing that I can reveal on this public newsgroup.

Although I not that worried about the Mico32. Most of MicroBlaze competition (and I also think that is the same for the other soft processor) is not other soft processor but rather standard processors.

I just trying to get enough good performance and features in the Microblaze. Together with a low cost FPGA you can make a business case of replacing a standard processor with a soft processor inside the FPGA. Of course the customer needs to have a FPGA in the product already so they are familiar with FPGA and the soft processor is only a delta-cost of the extra needed LUTs.

Customer totally unaware of FPGA are not very likely to in a new product start using FPGAs and at the same time start using soft processor.

Göran

Reply to
Göran Bilski

I actually picked that up here in the NG.

Anyway, since you obviously know more about MB than the random NG posters, I take it that it can be done

Reply to
burn.sir

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