Posts: 4
Registered: ‎07-11-2014

How long does S6LX16 take to boot?

I'm just starting on paper with the Spartan-6 LX16 development kit.  I don't have one in hand yet.  Before I buy...  How long does it take this board to boot up?  Is it a milliseconds kind of time frame?  Or a many seconds to minutes kind of time frame like many embedded linux systems?  I'm hoping it's far under a second.

Avnet Employee (Star Contributor)
Posts: 114
Registered: ‎06-09-2009

Re: How long does S6LX16 take to boot?

Hi helmutforren,

I am afraid that this board won't boot Linux in the time frame you desire. Can you elaborate on your application which requires Linux to boot under such a short time duration?

I timed my Spartan-6 LX16 board using the out-of-box demo application and came up with the following numbers. From power on to Programmable Logic (PL) config DONE takes about 2.5 seconds at that point MicroBlaze code begins executing. It takes the bootloader another 9 seconds to load the main application code to LPDDR SRAM, load the Memory File System image into RAM, jump execution to the main lwIP application, and reach a command prompt.

Keep in mind that all of this happens on an FPGA and the application code executes on a soft processor (Microblaze) implemented in the PL. The advantage of the FPGA is that you have a lot of flexibility to customize that programmable logic hardware. However, you could get higher processing performance out of a hard processor implementation like the Cortex-A9 MP core of Zynq-7000 devices.

If you are looking for something like that, we have the MicroZed Eval Kit set at nearly the same price point as the LX16 board and you can find more information on our community site.

I have a lot of nostalgic bias toward the LX16 Eval board though. It's got a Xilinx Series-6 FPGA, a Cypress PSoC3 device, a ton of expansion I/O, and a rechargeable Li-Ion battery cell to power it all. You might be able to pull a few tricks to get it to boot slightly faster and I think you can run a slightly faster PL config clock but its definitely going to take more than a second to configure the FPGA fabric, let alone boot application code.


Posts: 4
Registered: ‎07-11-2014

Re: How long does S6LX16 take to boot?



Thanks very much for your thoughtful reply.


In fact I do *not* want embedded Linux.  I have not yet had time to study much of the internals of the Spartan-6, so I wasn't sure yet what this MicroBlaze was about.  I deduce from your post that it's a cludge of a processor built out of FPGA components.


My primary interest in the dev kit is both the Spartan-6 and the PSoC3.  I have a lot of PSoC intellectual property, and it is a good platform to be my main platform for this new custom product design.  My interest in the Spartan-6 is merely to (A) receive 8 simultaneous channels of ADC data at under 1kSPS, (B) filter it through a complex series of multiply-and-accumulate [MAC] steps, then (C) downsample the data to get possibly 1SPS per channel that gets passed to the PSoC.


So I think your 2.5 seconds to get the PL running will hopefully be a comparable time to what it takes to get my MACs running and therefore hopefully data flowing into the PSoC.  I can easily "hide" that from the user with a logo splash output.  If the MicroBlaze is required in some way -- to configure my ADCs, effect the down sampling and PSoC communication, or something else -- then I guess I'll have to just try to make that as streamlined as possible.  A total of 11.5 seconds is approaching an order of magnitude slower than just 2.5 seconds (duh!), so that would be more difficult to "hide" from the user.  Maybe my MicroBlaze program would be smaller and faster to load.  We'll see.


For the moment, this is all prototype.  So I won't necessarily be married to any of these dev kits.  I have gotten the impression, though, that the Spartan-6 is the right low-power device for my digital filter MACs and down sampling.  It's probably far, far more powerful than I need.  But there's a chance my 1kSPS input rate could skyrocket after further R&D.  So having the excess capability is a plus.


I have a prior product into which my associate designed the Critical Link mitydsp-l138f.  It has an embedded Spartan-6.  It's ready long before the linux.  I have a little programming experience on that FPGa implementation, but no pcb design or general setup experience with the Spartan-6.  That won't stop me though.  I do have 39 years programming experience, on too many platforms to count, large and small, with an equal amount of electronics experience.  It's just this particular guy I haven't used before.


Nevertheless, if something comes to mind that might be a better low-power fit to my MAC need, please DO let me know.  There are so many options out there, one can't become an expert on all of them in order to make the omniscient best choice.  About these MACs, I haven't calculated my exact FLOPS or MIPS needed, but it's not too great.  So far as MAC stages, it will be less than 80 probably, and could be as small as 40.  Divide that by 8 for my prototype need (single channel).  Obviously, some flexible wiring between MAC stages is needed.


Thanks again,