$7 for 80MHz 32 bit microcontroller with ethernet

Have you looked at the AT91SAM7X256 (Atmel). Not quite the speed in MHz you spec but may be fast enough in guts.

Regards, Richard.

Thank you for replying. I did look at Atmel a while ago, but I forgot about it. The AT91SAM7X256 is pretty nice.

But I really need 100MHz and 80MHz is pushing it (in my simulations). Also, Arrow lists this part at $18 so a real 1k price is probably $9.

Alan Nishioka

Arrow web prices are very high and not consistent in how high they are relative to "real" prices. I got a quote on this part. I don't have it handy, but I think it was in the $7 ball park. I'll check tomorrow and post again. But if the speed is not there, then it is not there.

You don't say what else you need. Speed varies greatly depending on execution from Flash or from RAM. I have seen parts with larger and smaller amounts of RAM which should make a big difference in speed. Also, do you need on board Flash? I have not finished my ARM device comparison chart, but I believe there are ARM9 parts that meet your needs if you can work with external Flash... not sure of a $7 part. Check

for an ARM7 comparison chart... Resources page, scroll down to ARM Chips and select ARM device comparison chart.

What happens if there is no part that meets your full requirements? Do you relax a requirement or do you not build the product?

I should have said in the beginning that I have been planning on using a Xilinx Spartan3 250E and a Microblaze core (This is where the 80MHz and $7 comes from). Since others have said fpga solutions are expensive, I was wondering if I could do it cheaper with an Arm or Blackfin or something else. If the price is comparable, I am going with Microblaze.

And thank you for the Arm chart.

Alan Nishioka

I saw this awhile ago, don't know anything about it.

but, if you looking at FPGA designs, this might be a fit.

donald

You are welcome. But if you are comparing a Microblaze core with a complete MCU, how do you account for the onchip Flash and other features that you don't get in an FPGA core CPU? I guess you are not using any of that?

Well, an fpga can have integrated peripherals (uart), ram, ethernet mac, sdram controller, so I think it is a fair comparison to a microcontroller.

I will have to spend another $1 on a serial flash.

But I really only care if it can do what I want for what I want to pay.

Alan Nishioka

The key to the Microblaze performance seems to be that it is executing out of internal SRAM. There is a grand total of 31 kB SRAM in the device so you will have a hard time to fit a TCP/IP stack and application into internal memory. If networking performance is an issue, then you probably want to use a significant part of that SRAM for TCP/IP buffers. The Ethernet MAC will minimum require 4 kB, (8 kB recommended)

To get 80 MIPS performance out of the Microblaze you will need to have 80 x 4 = 320 MB / second bandwidth from your memory system. A cache will help somewhat, but only when you have cache hits.

so you are looking at a 32 bit memory system using either SDRAM or very fast synchronous SRAM.

If you execute out of cheap external 16 bit flash memory, then you are going to see 20 MBytes per second bandwidth and 5 MIPS with the Microblaze.

--
Best Regards,
Ulf Samuelsson
ulf@a-t-m-e-l.com
This message is intended to be my own personal view and it
may or may not be shared by my employer Atmel Nordic AB

Yes, that is the point. I am trying to find out if you have considered the differenced in memory. Most CPUs are deisgned to optimize memory with the processor speed. If they run faster than Flash can be accessed, for example, they either pipeline the Flash, use cache or provide enough SRAM to shadow the Flash. The typical CPU in an FPGA does not have the same bandwidth to a large memory, but is either optimized for smaller memories or is limited by external memory speeds.

But if you have considered this, I assume you know what your requriements are.

I would think it mandatory to run the processor at least partially from internal code memory, but far less important to use internal memory for all the data, such as network buffers. Network is comparatively slow, so some delay in getting at it's data may be okay. And we don't really know that network performance is important to his application - maybe only a singe packet needs to be buffered (though there are some tricks involving that and the nagle algorithm in whatever you are talking to - using the same memory for two smaller packets may work better).

Also, on caching, some really really high performance architectures pushing the limit of the technology they are implemented in often don't use caches, but instead offer small high speed memories where the programmer/compiler can choose to locate the most important code or data (was told most Cray designs do it that way). With carefull design this is a win, because these decision makers are a lot smarter (and can benchmark the alternatives) compared to some logic trying to make caching decisions at run time.

It would be interesting, and perhaps suprising if an FPGA implementing nothing that is not a common microcontroller on chip peripheral could come out cheaper than any microcontroller, but I suppose it's possible if no one has targeted a chip to that particular niche yet. Putting the entire ethernet interface (except magnetics) on chip does seem to be a recent thing, so maybe their is not yet a full range of processors with this feature.

Hmm, what about that broadcomm MIPS chip in the linksys WRT54G, I think the BCM5352? Clock speed is something like 200 MHz and it seems to include the MAC, possible even the switch as well. Can't be costing them much when the whole box is sometimes at little as $40, though there volume must be huge.

Assuming Broadcom talks to you. My experience is that they are not interested in talking to but a few companies worldwide.

--
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may bot be shared by my employer Atmel Nordic AB

Try the Freescale MCF5208 more Mhz and lower price.

Or close to your 7.00 price is the MCF5270

We have a full set of tools, RTOS and TCP/IP stack for all of these.

Paul

Cirrus 93xx ARM9?

David Collier

email can be sent to Dexdyne.com , under name from_usenet@

and which one 93xx cost $7?

Best regards Tsvetan

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