What FPGA content would you like to see?

1) tutorials on VHDL and/or Verilog

2) tutorials on vendor tools (i.e. Xilinx, Altera, Modelsim?)

3) information on where FPGAs have advantage over microcontrollers/processors (i.e. parallel versus serial logic)

David,

Thanks for the feedback. You pretty much read my mind and my plan. I have been looking at tutorial content to see what's viable. I have been thinking about bringing in tutorials on the Vivado Design Suite (Xilinx). Point 3 is good. But also was thinking about FPGA vs FPGA Soc's (programmable SoCs). A number of dev boards exist that use this architecture for their purported advantages.

There is an upcoming CEC training session on programming FPGA devices at Digikey.

You might want to check out what they have available.

DAB

DAB wrote:

 

There is an upcoming CEC training session on programming FPGA devices at Digikey.

 

You might want to check out what they have available.

 

DAB

Here's a link: https://www.designnews.com/continuing-education-center

Course runs from 9/11/17 through 9/15/17, each day with a 45 minute lecture plus chat.  It sounds like a decent syllabus, but it doesn't say which FPGA family it's going to use or whether there's a specific board.

i recently picked up  DE-0 nano to play around with and i was faced with the decision of SOC or not but ended up choosing not to go that route as i wanted to keep things simple. some good comparisons or examples showing theadvantageus/disadvantage of going the FPGA SOC route would be great.

the more tutorials the better i think as thats the best way to pick up new skills and learn.

Matthew McPhail wrote:

 

Some good comparisons or examples showing theadvantageus/disadvantage of going the FPGA SOC route would be great.

Many years ago the company I worked for considered using a Xilinx Virtex-II Pro for the next generation of our product.  Virtex-II Pro combined an IBM PowerPC core and a reasonably powerful FPGA.  It seemed like a great idea, but then we looked at the pricing and gulped.  We were much better off with an IBM PowerPC 405EP (really groovy chip) with a separate Xilinx Spartan-IIE FPGA (also groovy), using a 33 MHz 32-bit PCI bus to communicate between them.  Best yet, they both needed +3.3V and +1.8V, so our power regulation was clean and simple.

Virtex-II Pro didn't do well from what I've heard.  Along with high prices, the software was difficult and it had the design defect that you had to load an FPGA bitstream before you could boot the PowerPC.  That meant you couldn't use the PowerPC to download the FPGA bitstream as part of the boot process.  That's an important feature so you can ship a new version of the FPGA configuration along with a new software release, making both the software and hardware upgradable by users.  It also means the software dudes can get started before the FPGA works, and you can use the processor to debug the FPGA.

I think Xilinx was smart enough to fix this with Zynq.  So now you're mostly left with high Zynq prices.  I haven't heard anything good about the CPU software.  I've never Vivadoed, so I don't know whether to believe the people who say it's wonderful or those who say it's a pain.  Since there's no open source FPGA tool chain for Zynq, it's not really of interest to me at this time.

The chief advantage of an integrated FPGA/SoC is that you have very high bandwidth / low latency connectivity.  If you don't need that, you're better off with a separate SoC with good SPI capability or a good external memory bus.  Our design with PPC405EP and Spartan-IIE worked really well with PCI, but it's become really hard to find SoCs with PCI.  You can get PCI Express, which is great, but you can't find cheap FPGAs that have PCIe.  Xilinx has some PCIe Spartan-6 chips, but they have lots of logic so they're really expensive.

John Beetem wrote:

 

Many years ago the company I worked for considered using a Xilinx Virtex-II Pro for the next generation of our product. Virtex-II Pro combined an IBM PowerPC core and a reasonably powerful FPGA. It seemed like a great idea, but then we looked at the pricing and gulped.

Yep we had the same thing at a company I was working for. We thought it would be perfect for our application then took one look at the eye watering prices and escorted the Xilinx rep off site.... We ended up with a Freescale PowerPC and Altera FPGA's in the end which worked really well.

John Beetem wrote:

 

Along with high prices, the software was difficult and it had the design defect that you had to load an FPGA bitstream before you could boot the PowerPC. That meant you couldn't use the PowerPC to download the FPGA bitstream as part of the boot process. That's an important feature so you can ship a new version of the FPGA configuration along with a new software release, making both the software and hardware upgradable by users.

Agreed, being able to configure the FPGA from the system processor is a big benefit. It also saves the cost of the config EEPROM from your BOM too.

John Beetem wrote:

 

Our design with PPC405EP and Spartan-IIE worked really well with PCI, but it's become really hard to find SoCs with PCI. You can get PCI Express, which is great, but you can't find cheap FPGAs that have PCIe. Xilinx has some PCIe Spartan-6 chips, but they have lots of logic so they're really expensive.

What do you define as expensive? Devices with PCIe endpoints in Xilinx and Microsemi are both available for around $45 in one off quantities on Digikey. Strangely Altera seem to be in the hundreds of dollars for a PCIe capable part.... maybe I am missing something....

Best Regards,

Rachael

That's cool that you had a similar Xilinx Virtex-II Pro application and ended up with the same approach we did.

rachaelp wrote:

What do you define as expensive? Devices with PCIe endpoints in Xilinx and Microsemi are both available for around $45 in one off quantities on Digikey. Strangely Altera seem to be in the hundreds of pounds for a PCIe capable part.... maybe I am missing something....

Our application only needed a $20 FPGA.  We only needed the PCIe for low-latency connectivity.  We only used up to 10-20% of the 33 MHz 32-bit PCI bus (1 Gb/s raw), so only 5-10% of PCIe 1.1 (x1 = 2 Gb/s in each direction).

That's cool that you had a similar Xilinx Virtex-II Pro application and ended up with the same approach we did.

rachaelp wrote:

What do you define as expensive? Devices with PCIe endpoints in Xilinx and Microsemi are both available for around $45 in one off quantities on Digikey. Strangely Altera seem to be in the hundreds of pounds for a PCIe capable part.... maybe I am missing something....

Our application only needed a $20 FPGA.  We only needed the PCIe for low-latency connectivity.  We only used up to 10-20% of the 33 MHz 32-bit PCI bus (1 Gb/s raw), so only 5-10% of PCIe 1.1 (x1 = 2 Gb/s in each direction).