View Full Version : Unsolved AVR and FPGA knowledge request?

03-08-2012, 03:36 AM
Ok, i have been sick + college = no time to do anything
now i am about to order a new batch of parts inculding 3 props and one wdc65c02 and a few atmegas
here is the problem
i want to start with FPGAs and what i need to do that i cant figure out.
i started with the propeller with the serial to prop adapter as its cheap and easy.
and the prop to write a program for it easy just download the proptool IDE!
well i decided to ask you guys for advice.
what to use to get started easy and cheap on atmegas and FPGAs
oh why FPGAs well i made some interesting stuff in LOGISIM (wich is a good digital circuit simulator)
and i want to make it real
here is a peice of my CPU i am making
it opens with logisim
i intend to make modular sub componet CPU with a seperate command core ALU and memory maneger. so i can then use ramchips or registers as system registers and make the CPU scalable if you open this please note the way my X an Y registers are configured they can be functioned together or either can be functioned against a ram byte and the intended scheme is paired ram banks with automatic tracking of which byte has an instruction i am still working out the details of my command core and how to scale the register memory. pretty fun eh? :tongue: now if any of you want to help YAY thanks big thumbs up and plus i will make sure to include thanks in my code. thats all i can do for you if you help.

03-08-2012, 04:30 AM

Best bet, try one of the FPGA vendor forums for help.All the vendors are into doing synthizable cpu's so that's where the expertise is.

03-08-2012, 05:18 AM
what to use to get started easy and cheap on atmegas and FPGAs

A good starter place for FPGA is the Lattice MachXO2 Breakout Board. (LCMXO2-1200ZE-B-EVN) just $29.99
This has a FT2232H - one channel for ISP, and a spare channel for user link.

03-08-2012, 05:24 AM
thank you JMG that kind of advice is great.
$30 is pretty cheap
anyone know of a DIY option though i like DIY stuff, i learn better from that.

03-08-2012, 05:27 AM
I would use an FPGA from Xilinx or Altera. Here is one that I have used and enjoy: http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,790&Prod=BASYS2

I've also used this board: http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,400,897&Prod=NEXYS3

If you're interested, I'll sell you one of them for 50% student cost + $5 shipping (the BASYS2 contingent on me finding it...). I've had a bunch of fun developing on FPGAs, but it's difficult for me.

03-08-2012, 06:20 AM
sounds like a good deal, just one problem i got no clue as to the student value :lol:

is there any FPGAs on DIPs that are any good?

03-08-2012, 07:22 AM
thank you JMG that kind of advice is great.
$30 is pretty cheap
anyone know of a DIY option though i like DIY stuff, i learn better from that.

What do you mean DIY ? - Any Verilog/VHDL you code is certainly Doing it Yourself !!
The Board has 0.1" connectors, so you can integrate into anything you like.

There is nothing in DIP that will swallow a Soft-CPU.

03-08-2012, 07:27 AM

Take a look at the links I provided: they list a student price on the webpage. Usually students can get a significant discount. As far as DIP, unlikely.

I don't know about other FPGAs, but the Digilent boards have IO ports (they call them Pmod connectors) that can be directly wired to a breadboard, and they interface at standard logic levels (IIRC 3.3v).

03-08-2012, 07:58 AM
thanks SRLM i did look and that site is good the best option i think i found is the 40pin dip board and the comment was sorta meant to be funny to hence the little smily face :lol:
JMG thanks too i don't mind if the FPGA is not big enough for a whole CPU since it is a modular design i am after (if you want to look at my ALU) a design that will have parts of a CPU on different chips and use ram chips or addressable storage registers for registers. in fact it be awesome just to get started with any level of FPGAs so eventually i can make my own CPU.

but yeah both of you gave great advice. thanks really.
yeah i like to make my own cables and stuff i found some ok looking DIY cables to go from a parallel port to the FPGA but funny enough the person who posted it didnt have anything that he did with it so i am clueless as to what it can do. and the site didn't say how to use it so it could just be trolling.
it is a great way to learn to make all the stuff from scratch needed to use the stuff. or at least its my best way to learn :tongue:

03-08-2012, 08:30 AM
here is some nice stuff but nothing that makes me want to risk spending cash on FPGAs yet
and one question what level of logic can a macrocell emulate? one gate or an advanced function?
anyone got some good suggestion on AVRs i like the propeller but AVRs can do a lot more in the area of math functions or so i have heard, plus some AVRs are dirt cheap.
i have a hard time discribing my goals i know but thanks for helping me and putting up with this.
or if going for math is a PIC better?

03-08-2012, 09:03 AM
Cheap FPGA boards are available on Ebay. Most use the older Altera Cyclone II, but there is nothing wrong with that.