LatticeMico32

[alvieboy]

Hi Jack,

I understand you were able to put mico32 working on papilio. Care to share some details like:

* RAM size

* Number of LUT/Slices

* Integrated peripherals

Best,

Álvaro

[Jack Gassett]

Hello Alvaro,

 

  I didn't get much further then just getting it to blink some LED's. My  interest in it is for its Wishbone bus, I'm thinking that we should  settle on a standard for peripherals that all of the Papilio supported  soft processors can use. Whether it is Wishbone or something else it  would be nice to start developing peripherals that will work with the AVR8, ZPUino, and any future soft processors. Wishbone seems pretty heavy but I wanted to start getting more hands on experience with it to be able to better decide. What are your thoughts on a common peripheral bus? One nice thing about Wishbone is that there are a lot of Wishbone cores on Opencores.

As far as the details of LatticeMico32:

I just implemented a reference design, my interest is exploring Wishbone.

• It has 32 bit wide memory that is 4096 deep.
  
• 32Mhz speed directly from external oscillator.
  
• GPIO is the only peripheral included.
  
• Wishbone controller is included.
  
• Size, it is using 97% of the Papilio One 250K slices which is not very good. This alone may eliminate our doing anything serious with it. There is no room left over for peripherals on the Papilio One 250K.
  

Jack

[alvieboy]

Wishbone seems pretty heavy but I wanted to start getting more hands on  experience with it to be able to better decide. What are your thoughts  on a common peripheral bus? One nice thing about Wishbone is that there  are a lot of Wishbone cores on Opencores.

Actually the very basic of Wishbone is very simple. What makes things a bit complex is the bus mastering. If you only have one bus master (the CPU) then things are quite easy.

ZPUino can support Wishbone easily, just needs to translate 2 or 3 signals. But only the basics, meaning no full transactions, no masters, no burst transfers.

32Mhz speed directly from external oscillator

What says synthesis about max frequency ?

Size, it is using 97% of the Papilio One 250K slices which is not very  good. This alone may eliminate our doing anything serious with it.  There is no room left over for peripherals on the Papilio One 250K.

I always thought it would be quite smaller than that. Do you have the detailed map report ? Perhaps the Wishbone master is eating all your slices. That happened to me with OpenRisc32.

ZPU Core Premium is now using about 1K slices, but for example GPIO plus the peripheral pin select stuff eats more than twice that value. Muxers are a killer. Spartan6 and the Kinetix seem to have larger muxers, but they are expensive and have limited support on ISE WebPack.

Álvaro