FPGA's- id really love an answer to this

[Ubergeek63]

Oo I've been steered away from Actel, purely because in university we dealt with Lattice/Xilinx stuff, so I've built up development tools for those. I am aware that Actel is highly professional, as I seem them used quite often in proper high-end systems. I beileive Xilinx and Altera are aimed far more at the education market, to get peeps 'on board'.

Pretty common tactic. M$ is doing it consistently in developing conutries, bribing them to use M$ crap in the hope that the rest of us continue paying them protection money.

I tend to use CPLD's, possibly small FPGA's for the raw logic, such as your counters/ram controllers/LCD controllers etc.. with a micro doing the bulk of the system management. Essentially using the FPGA purely as a custom peripheral, interfaces with SPI/parallel etc.. Antoher exampel is a 200MSPS digital storage scope I'm working on.

That runs a counter in the FPGA, an external delay line for sub nanosecond resolution, and a 100MHz A/D feeding a 100MHz FIFO for a scope function.

Hmm seems this thread as steered into an avert for FPGA's lol, I hope the OP doesn't mind, and perhaps gain more insight into jsut 'why' the designer of his MP3 player went down that route.

If the OP requires more info on alternatives to FPGA's in hard-disk based mp3 player, I do have some bookmarks that may be useful. Mainly university projects, or little geek rants by fellow techies about trying to get adata too and from a IDE hardisk as cheap as possible.

Dunno, the thread title was FPGAs. If he is using RAM based units it would make sense that he could do all the heavy math in the FPGA just by reconfiguring it on the fly for what ever format was currently playing.

Some of them, and perhaps most these days, will let you use control logic to call up configuration changes to change from MP3 to ogg, say. Having the logic reconfigure itself on the fly like that can save a lot if there are a large number of big functions that need to be run in a small FPGA.

 

[Ubergeek63]

No need to defend me at all - I stand by my post, PIC's and other micro-controllers have taken over the role of FPGA's in some applications.

They are cheaper and simpler to use - I also said, which you seemed to ignore, that FPGA's are MUCH faster, where PIC's (or even quad core PC processors) aren't in the same league.

FPGA's were used in a lot of applications where their speed and power weren't needed, and can now be replaced with cheap processors.

And if you think it takes 5-10 years for items to get to repair benches, you're living in cloud cuckoo land!

Off hand I can't even think of a domestic item that uses an FPGA?.

Curious how you contradict yourself...you are either in the position to know or you should not presume to comprehend.

It takes a year to get from the announcement of a component to the point that it is a good idea. It takes another year flood the supply chain. It takes another year before the standard year warranty is up. So that make for an absolute minimum of 3 years between the time I see it and the time you have a chance of seeing it.

Now you can factor into that an infant mortality rate of probably 5%, and I have to assume that there are over 100 repair shops in Europe. If they make a million units, Europe gets say 100K. But there are over 100 shops so you are down to 1000. Infant mortality brings the number to 50. So your shop has a chance of seeing 50 units after 5 years, though I suspect there are more shops than that. If it has not failed at that point, barring getting thrown off a roof, it will probably last 10 or more years.

The fact remains that were it not for this medium I would know about components and how useful they are in industry 5 years before you. That being the case you are in no position to be making judgments as to what is replacing what today.

 

[andy257]

To answer the original posters question. You dont need to use an FPGA to make your mp3 player, not unless you want to actually make the mp3 decoder part yourself.

There are many micro controllers available with in built mp3 decoders, just do a quick search on google. They will contain the usual toys (A2D, SPI, I2C etc + mp3 decoder).

i myself based my final year project at uni using an FPGA. I did not use an mp3 decoder but the storage control and handling of the digital data was all done using the FPGA.

The hardest part about the dissertation was justifying why i used an FPGA when a uC could have easily done the job. I did it because i wanted to show an alternative way of doing it. Showing the benefits a PLD can bring to the table and how easy and cheap they are to use compared to 5 or 10 years ago.

Its horses for courses really! you decide how best you can use your skills with the hardware available to you.

 

[kjennejohn]

Hi. I recently purchased a Mach64 Tutorial Kit from Nurve for $160 (sale price, $200 otherwise). This has a Lattice ispMach4064 on it. This is an offering from Andre LaMothe, of XGameStation fame. I find his writings clear and straightforward. I figured he would give me the handholding I needed to take on an otherwise daunting task. He starts with programming in ABEL and discusses CPLDs, then segues into FPGAs. The details are at:

**broken link removed**

Also, I have been (lazily) trying to find a way to emulate the GSC (Global Serial Channel) on an Intel 80C152. This handles SDLC, a subset of HDLC, all of which is used to do synchronous communications where the clock is embedded in the data stream. I have to implement NRZI and bit-stuffing to start with. Any of you CPLD/FPGA gurus know where I might find simple discussions or guides as to how to do the last two items mentioned in logic gates? Or, better yet, a site discussing this using ABEL on a level suitable for a logic technician trying to get ahead?

Sorry if this is thread-jacking but this seemed the place to bring both subjects up.
Thanks for any help or advice in advance,
kenjj

 

[Mikebits]

Off hand I can't even think of a domestic item that uses an FPGA?.

I would not expect to see FPGA's used in large scale productions. These devices usually are a precursor to an ASIC. Considering the cost of an ASIC, it makes more sense to stick with an FPGA in small production runs, like less than 5000 units per year. I am not really sure when the unit count would bend towards going with an ASIC, but for commercial items like a cell phone, ASIC's would be the way to go.

 

[tkbits]

3VO, for a software winkidink such as yourself, I think VHDL would come very naturally as it resembles sw.

Beware! Being a pro at software does not necessarily translate well to logic design. VHDL and Verilog look so much like SW languages that you can get suckered into coding FPGAs like MPUs. You'll get strange messages like "Multiple sources for signal XXX" or strange terms like "combinatorial loops" as a result of treating VHDL/Verilog assignments like software assignments.

 

[Mikebits]

To use VHDL you need an understanding of the logic to be sure, but VHDL is nothing more than taking black boxes and connecting them via code. Like C, VHDL has reserved words, and a syntax. I think the transition from C to VHDL would not be a major task, learning curve maybe. There are in fact C to VHDL compilers out these days. Never tried them though.

**broken link removed**

 

[Nigel Goodwin]

It takes a year to get from the announcement of a component to the point that it is a good idea. It takes another year flood the supply chain. It takes another year before the standard year warranty is up. So that make for an absolute minimum of 3 years between the time I see it and the time you have a chance of seeing it.

What on earth are you rambling about?.

Freesat+ HD PVR - concept developed April 2008, product in the shops November 2008 - that's 8 months from concept to me seeing it, and that's an exceptionally long time for a product to take.

I've often seen, and repaired, new products even before they are released as well, you obviously have no idea at all about domestic electronics.

 

[tkbits]

To use VHDL you need an understanding of the logic to be sure, but VHDL is nothing more than taking black boxes and connecting them via code.

And that's the easiest thing to forget when writing "sequential" code. Until it gets pounded into your brain that "sequential" code in "synthesizable" VHDL or Verilog is NOT sequential, you can easily stumble by writing MPU-like code.

If you forget that it's all parallel, you end up writing this kind of logic:

Read signal from antenna.
Move antenna signal to tuner.
Move tuner output to detector.
Move detector output to amplifier.
Compute feedback signal from amplifier output.
Combine feedback with detector output and move results to amplifier input.
Move amplifier output to speaker.

And the development software will tell you it can't create what you thought was possible.

 

[Blueteeth]

On the subject of HDL languages...

I find ABEL quite useful for simple-medium complexity deisgns, then I turn to verilog, its more C friendly htan VHDL. But even then I often (about half the time) do it all in raw schematic entry

Of course thats not an option for large designs, and its usually used to connect up blocks visually, rather than having to use the 'wire' command. But I've optimised several designs with schematic entry, and occassionally you can save a hell of a lot of resources (12,8 hamming decoder + manchester decoder in 32MC @ 100Mhz). That probably means that my HDL language skills were crap, as you can easily see whats going on with buffers, gates and registers when they are right in front of you.

All you really have to remember is, you construct things in 'blocks'. If sequential design is your bag, write a state machine - often the best way for the high level top design, which just sends out control lines to peripheral blocks. But as mentioned many times, unlike 'software' you can have several things going on all independant of eachother...they don't even have to share the same clock.

Blueteeth

 

[Ubergeek63]

What on earth are you rambling about?.

Freesat+ HD PVR - concept developed April 2008, product in the shops November 2008 - that's 8 months from concept to me seeing it, and that's an exceptionally long time for a product to take.

I've often seen, and repaired, new products even before they are released as well, you obviously have no idea at all about domestic electronics.

I'm saying I hear about components years before you see them.

I'm saying that the components need to be on the market before you hear about the "concept developed" because the actual concept developement needs to happen before the silicon developement can begin, and the silcon has to be in high volume production before the "domestic electronics" production lines can be started.

Now, unless you would have us all believe that your two bit repair shop is getting the engineering prototypes to repair, there is no way that you could be seeing the components in the time frame you are claiming. If that is that is the case then you are also expecting us to believe that you are more educated and skilled than the design engineers to be able to repair it sight unseen when we all know that you are getting step by step instruction as to how to repair what they trust you to in a full run production product.

 

[Ubergeek63]

I would not expect to see FPGA's used in large scale productions. These devices usually are a precursor to an ASIC. Considering the cost of an ASIC, it makes more sense to stick with an FPGA in small production runs, like less than 5000 units per year. I am not really sure when the unit count would bend towards going with an ASIC, but for commercial items like a cell phone, ASIC's would be the way to go.

actually the pricing is now to the point that it makes sense to use them in all but the highest volume, most stable designs.

ASIC developement costs 100K per mask run, and there is often 3 or more mask runs to get to a production ASIC. FPGAs can do multiple "mask runs" a day, and once it works properly, some FPGA manufacturers have ASICs that are based on the same masks that are used in the FPGAs so you are assured of FPGA timing in the resultant ASIC for a very small mask charge.

 

[Nigel Goodwin]

I'm saying I hear about components years before you see them.

Obscure components not used in domestic equipment perhaps, but IC's specifically designed for TV use (or similar) I would suspect not, you probably never see them at all, and the time to use in production sets isn't 'years' in the first place (not if they want to make money).

I'm saying that the components need to be on the market before you hear about the "concept developed" because the actual concept developement needs to happen before the silicon developement can begin, and the silcon has to be in high volume production before the "domestic electronics" production lines can be started.

Makes you wonder how manufacturers make any money?, if (according to your ideas) IC's have to have been in production for years before anyone uses them?.

Now, unless you would have us all believe that your two bit repair shop is getting the engineering prototypes to repair, there is no way that you could be seeing the components in the time frame you are claiming.

You appear to have a problem with your manners, I can't help noticing that many of your posts are insulting and discourteous to other members - perhaps you should try been polite occasionally?.

You have no idea where I work, or who I work for - and (obviously) no idea of the time frame I see components in.

If that is that is the case then you are also expecting us to believe that you are more educated and skilled than the design engineers to be able to repair it sight unseen when we all know that you are getting step by step instruction as to how to repair what they trust you to in a full run production product.

By definition many warranty products initially have no service information, and you have to "wing it", and where do you get your ridiculous assertion that we get "step by step instruction as to how to repair"

Over the years I have seen many items pre-production, manufacturers used to quite often bring them round to ask our opinions, and as an engineer I normally would disassemble them (if allowed) to comment on their quality of construction. On a number of occasions I have also had to repair such items, as they didn't work when the sales team brought them to show.

This is less common now, with all companies having cutback over the years, and running on much smaller workforces.

 

[andy257]

Nigel maybe you should lock this thread now, i think its went way beyond what the OP asked in the first place. It seems to just be a place that is used as a slagging match on who knows more about FPGAs and for people to confirm to themselves what i could get from google in under 5 mins. Its not actually serving any purpose anymore in my opinion.

 

[Blueteeth]

Agreed. This isn't the OP's fault at all...I'm still waiting for detailed info on hard-disk management for portable apps such as MP3 players

 

[Ubergeek63]

Agreed. This isn't the OP's fault at all...I'm still waiting for detailed info on hard-disk management for portable apps such as MP3 players

Well an FPGA is not your answer since it is so complicated ... I don't recall any hint as to how much the OP was willing to go through, nor any clue as to his skill level aside for the fact that he asked about FPGAs. An MP3 player is far beyond a hobbyist's skill level and would be of considerable cost compared to commercially available ones.

As to something that could be handled it is all done already in a FTDI VMUSIC:
http://www.vinculum.com/documents/datasheets/DS_VMUSIC2.pdf

I am not sure what the audio chip is in there but I know that is just an FTDI Vinculum chip and a third party mp3 chip.

Even those are beyond the skill level of many hobbyists since, while they do all the work for you basically exposing a simple command interface, they are both fine pitch SMT parts.

 

[Ubergeek63]

And here it is thanks to a simple search on google and uses your hacker's favorite micro to boot!

020 - EchoMp3 v1.4 - MMC/SD Card MP3 Player

A complete MP3 player with SD FAT, LCD and digital audio interfaces on a PIC with the VS1002 audio chip. Of course you are talking about either paying $75 for his kit or paying $20 or more for parts to put together when you can buy for $10. Ok for leaning I suppose, particularly if you are int school of hard knocks!

 

[Blueteeth]

I beileve the OP was refeing to the design of a kit he had which was a hard disk player, not flash. Agreed an FPGA isn't need for flash/SD cards, but IDE? Sure now days flash is just a hell of a lot easier but maybe some people would like 400GB storage without having to pay through the nose for solid state memory

 

[BeeBop]

You appear to have a problem with your manners, I can't help noticing that many of your posts are insulting and discourteous to other members - perhaps you should try been polite occasionally?.

I'm not sure it is manners, Nigel. I think it is attitude; he seems 'way up there,' as opposed to the rest of us, down here.

I look at how helpful some people here are, and they seem quite humble. Others seem to only present facts on how much smarter, or more knowledgeable they are.