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Topic: Arduino Due/SAM3X8E, versus LPC Xpresso/LPC1768 (Read 5854 times) previous topic - next topic

jwatte

So, regarding the Arduino Due:
The closest I can think of in currently available hardware would be the LCP Xpresso 1769 (or the slightly cheaper 1768 CPU):

The SAM3X8E seems to be priced a couple of bucks higher than the LPC1768 ($13 vs $11 in small quantities.)
The LPC Xpresso has a sub-$30 form factor, although it's not very non-engineer-friendly.
The LPC1768 is faster in MHz (100 vs 84).
The SAM3X8E has more SRAM (96 vs 64).
The SAM3X8E has faster USB (Hi-Speed vs Full-speed)

What are some other differences between the two CPUs? (I have full confidence that the Due will be better productized for regular people than the Xpresso boards)
I tried googling for a comparison, but apparently nobody has written one up yet.

westfw

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What are some other differences between the two CPUs?

The peripheral sets (everything that isn't part of the "ARM core") will be entirely different.
The LPC Xpresso is a "subsidized" evaluation board provided by the manufacturer.  It's probably not fair to compare it's price to the Due, which I'd expect to support the full Arduino two-tier distribution system.  OTOH, it's also not fair to totally ignore the nice price of the Xpresso, either.

Graynomad

#2
Jun 15, 2012, 10:13 am Last Edit: Jun 15, 2012, 05:03 pm by Graynomad Reason: 1
One difference is the power supply handling that the SAM3 has, it can shut down an external regulator (using it's SHDN pin) thus turning itself and anything else completely off with the exception of the smallest amount of hardware used to monitor various wakeup sources.

That's a great feature and it's not available on the LPCs.

OTOH the LPCs have 8 and 16-byte FIFOs on the serial peripherals. I think that's a good feature.

Off the top of my head some differences are

LPC has
  4032 bytes of EEPROM
  LCD controller
  3 I2C
  CRC engine

SAM has
  DAC
  2 I2C
  True random number generator

Overall I think the LPC wins but of course it depends on what you need.

One thing is for sure the LPC forum is nowhere near as active as this one. You do get answers there though so it's good in that way.

The Due will be better productised than the Xpressos for sure, that said I recently downloaded the LPC Xpresso IDE and had a working (well compiling, I have no hardware) program with multiple files (one of which was some assembly language) in minutes. So for anyone that's at least semi-experienced (and beginners don't need either platform) I think the Xpresso environment seems to be a winner and the hardware is 2-3x cheaper than what I assume the Due will cost. Admittedly I don't think the Xpresso boards have USB once you break them from the LPC Link debugger although that's probably just a couple of resistors.

Another thing about the LPCs is the range of processors, you can go from 208 pins right down to 33 and even 16 "pins" (actually a 4x4 bump package), even dual core, all with similar IO hardware, and lets face it the processor core is pretty much irrelevant to 99% of programmers who work with C, but learning a new set of IO peripherals is a real pain.

I was a big fan of the SAM3, I even designed a Due-compatible PCB and was keen to start developing code for the Due, but there has been (and still is) almost no information released. If there had been some feedback to the potential users (that's us) I may have hung in there, we'll see what happens with the Due but for the time being I am about to order have ordered 4 LPC Xpresso boards and hit the LPC trail.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

jwatte

That's a good, hands-on-ish evaluation. Just what I wanted -- thanks!
I wish there were Xpresso options for the higher-end lines, too (2400, 3200.)

Leon Heller

#4
Jun 15, 2012, 07:54 pm Last Edit: Jun 15, 2012, 07:59 pm by Leon Heller Reason: 1
It makes more sense to compare the Due with the Digilent chipKIT Uno32:

http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,892,893&Prod=CHIPKIT-UNO32

The LPC1114 will soon be available in a DIP28 package, NXP gave me some sample chips and I designed a home-made prototyping PCB.

Leon Heller
G1HSM

Graynomad

#5
Jun 16, 2012, 12:45 am Last Edit: Jun 16, 2012, 12:47 am by Graynomad Reason: 1
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LPC1114 will soon be available in a DIP28 package

Yes I'd forgotten about that, a 32-bit processor in a simple DIP package will be good.

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I wish there were Xpresso options for the higher-end lines, too (2400, 3200.)

Or the 435x dual core (M4 and M0 processors in the same package), the LED blink program would really fly.

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Digilent chipKIT Uno32:

No matter how hard I try I just can't get enthused about PIC chips, I think it's a deep-seated bias from the days when they first came out and were completely brain dead compared to other chips at the time.

I've just ordered my Xpresso boards, we'll see how they go.

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

jwatte


the LED blink program would really fly


:-D

Actually, I'm more looking for the ability to use "big boy" tools like pre-emption and memory protection. I can use MIPS for good!

Also, the asymmetric-core option adds a lot of complexity, which pretty much only seems to make sense if you're making something that needs to do a bit of work at low power, and then occasionally do a lot more fancy work. But it's still not to the level where it could drive a UI like, say, an iPhone.

As for another option: The Raspberry Pi is kind-of-sort-of shipping, we'll-have-volume-soon scout's-honor style!
For $25 (or $35 with Ethernet) it'll do a *lot* of what these boards are doing. Drawback: I'll have to solder the GPIO jumpers myself, and it's kind-of light on board-level peripherals (SPIs, ADCs, and whatnot.)

jwatte

Aaand now that I look more at the Xpressos, you can't use any Linux tools with them. They seem locked to the Code Red trial tools. Blech.
The mbed seems better, and more expensive. If I go that way, I might as well go for a full BeagleBone. Or wait for the Due. Or wait for the Raspberry Pi...

Leon Heller

#8
Jun 26, 2012, 09:51 am Last Edit: Jun 26, 2012, 09:55 am by Leon Heller Reason: 1
The NGX LPCXpresso boards are used with the Coocox tools instead of the Code Red software:

http://shop.ngxtechnologies.com/index.php?cPath=21&osCsid=b1aaee725855798e1de88791d40aa41a

They sent me some of their boards for review (I run the LPC2000 Yahoo group). They are very good value, and the Coocox software seems to work just as well as that from Code Red, and doesn't have any restrictions. Both are based on gcc.
Leon Heller
G1HSM

jwatte

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the Coocox software seems to work just as well as that from Code Red


That's interesting to hear! Does it run from make files on Linux?

Leon Heller

Leon Heller
G1HSM

epam

While both SAM3X8E and LPC1768 include an Ethernet MAC, only LPC Xpresso seems to have an Ethernet PHY chip onboard.
This means that LPC Xpresso requires only an RJ-45 (with magnetics) connector, while Arduino Due would require a special Ethernet Due Shield so as to use the MCU's embedded Ethernet.

(judging only by the Arduino Due photos and not the final product, so if someone has more info, please enlighten us)

Graynomad

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so if someone has more info, please enlighten us)

Good luck with that :)

______
Rob
Rob Gray aka the GRAYnomad www.robgray.com

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