Soft processor: which one should I go for?

[J90]

Hi there,

So far I've been working on embedded projects using AT91SAM7 microcontrollers (an ARM7TDMI core plus plenty of peripherals, made by atmel).
Now, after messing around a little bit with a Spartan3 FPGA, I'd like to get it to do some real stuff.

At first I thought about the Microblaze, but after a little searching I discovered it's not free (well, it's free if you get your hands on a EDK license), so that's out of the question.
I checked out the internet and OpenCores, but wow, it's a sea of information in which is way too easy to drown.

So I'm asking you guys, what soft processor do you think I should go for? My target are embedded applications. A good support by GNU tools is also required.

BTW I need something not really "dumb" like a PIC (or PicoBlaze), I need something similar to an ARM7 as performance, maybe not as good, but comparable.


Thank you for your help

 

[lucbra]

Well, to be honest, I guess you're looking for the holy grail (like most of us do in the embedded world).
The constraints are pretty tight:
Free (like in free of charge or at no extra cost), there are only a handful:
Lattice Mico8, Mico32
OpenCores has a bunch of them
All the others are paying (need a license, or need to buy tools to support it)

There has been a project to port ARM7 to FPGA logic, but has been removed for obvious reasons (licensing)

Then there are the Cortex alikes (found in Actel devices) - not completely free but getting close I guess.

I don't know of others...

BTW: If you found the holly grail, don't forget to post the like here

 

[ryanlxb]

Hi, My arm-compatiable soft processor core is helpful to you.

https://code.google.com/p/arm-cpu-core/

It could run ucLinux in MODELSIM, and has a dhrystone : 1.2 DMIPS/MHz

 

[J90]

Wow ryanlxb, you implemented an ARM compatible processor on your own? I have to admit it, I'm impressed. Nice job!
Anyway I don't think I'll go for it, I need something more largely supported.


Well lucbra, I think I'll go for the Mico32:

http://en.wikipedia.org/wiki/LatticeMico32

If there aren't unexpected drawbacks, it's just what I was looking for!

Thank you for pointing me in the right direction


BTW @ those who are interested, check out this soft cores comparison :
http://www.1-core.com/library/digital/soft-cpu-cores/

 

[lucbra]

Hi J90,

I have to tell you that Mico32 is not as good as NiOS2. But it's free, and uses wishbone as the extension bus.
It doesn't really support multi master operation, and when you want to add new peripherals, it's not as easy as NiOS.

Anyway, no problem pointing you in the direction of Mico32.

Good luck and let us know how it goes.

Regards,