Getting started with FPGAs?

[ciipher]

Hi all,

I've been reading up a lot about FPGAs and I want to get into programming them, but the problem is I am not sure what type of FPGA to go for first as a beginner. I would also like to avoid having to buy expensive development kits too! Am I right in thinking that FGPAs are generally programmed in circuit? I'm especially interested in the projects hosted on www.opencores.org, some of which I would lik to implement.

Can anyone give me some pointers? As you can see I'm a little confused by the whole thing :?

 

[John Sorensen]

When I was looking for programmable logic, I jumped into CPLDs because they seemed straightforward and had a low cost of entry. I bought the Atmel ATF15XX development kit, which cost $100US, but really all you need is a chip, which comes in PLCC and TQFP packages so you'd need an adapter to prototype with it, and a dongle, which you can build yourself. It is a FLASH based device programmed through a JTAG interface, in-system programmable. Basic software is free. You can fit a whole lot of combinational and sequential logic into one of these babies.

j.

 

[ciipher]

Whats the difference between a CPLD and FPGA? If I were to locate schematics for and build a JTAG programmer, would it allow me to program any JTAG device, or would it be specific to a set of devices?

 

[crust]

An FPGA is usually more "integrated". You can get memory, clock generation logic, transceivers, etc on an FPGA, whereas a cpld is normally limited to combinational logic and small state machines. FPGAs are also usually much larger in their capacity, physical size, and price. There are some small FPGAs however.

As for JTAG, it is a relatively simple interface. You could probably use a JTAG interface with any chip provided the voltages are proper and you have the right software to control the part.

 

[laroche73]

CPLDs & FPGAs

Whats the difference between a CPLD and FPGA?

There's more to it, of course, but the following describes some basic differences between CPLDs and FPGAs:

https://www.electro-tech-online.com/threads/and721gst-lcd-display.2965/

Small CPLDs are simpler & less expensive to get started with, though you'll want a FPGA board to experiment with most of the designs listed on OpenCores. The Spartan (Xilinx) and Cyclone (Altera) series are the least expensive FPGA families, and a number of third-party development boards which use them are available. Free design S/W for these FPGAs is available on the Xilinx and Altera web sites. For relatively low-cost Xilinx-based FPGA development boards, take a look at XESS https://www.xess.com/ or Burched https://www.burched.biz/

For an Altera Cyclone board, try **broken link removed**

Electronics distributors like Arrow and Avnet also carry well-designed FPGA evaluation/development boards. (I have a Spartan and a Virtex board from Avnet, they make excellent development platforms).

I would also like to avoid having to buy expensive development kits

It's hard to find a true FPGA board for less than $100 - $150, the cost only goes up from there. You could try buying an FPGA and making your own PC board, it would be a good learning exercise in things not to do (FPGAs come in fine lead pitch quad-flat packs (QFP) or ball-grid arrays (BGA)). The $100 - $150 spent can save a lot of wasted effort.

 

[kinjalgp]

Check this: www.fpga4fun.com

 

[laroche73]

FPGA sites

nice site, kinjalgp. here are a few more experimenters' FPGA sites to check out:

http://www.mcmanis.com/chuck/robotics/fpga/index.html

**broken link removed**