Products > Other Equipment & Products

Review: mbed NXP LPC1768

<< < (3/4) > >>

NiHaoMike:
64kB seems way too little for a chip that has a 96MHz CPU and Ethernet. It's plenty for an ultra low cost microcontroller. The mbed is not one of those. Especially since Ethernet was never designed for very low power and many network applications are just asking for more memory.

TheDirty:

--- Quote from: NiHaoMike on October 08, 2010, 05:44:12 am ---64kB seems way too little for a chip that has a 96MHz CPU and Ethernet. It's plenty for an ultra low cost microcontroller. The mbed is not one of those. Especially since Ethernet was never designed for very low power and many network applications are just asking for more memory.

--- End quote ---
Yes, low power is a requirement of some embedded ethernet applications.  I'm not certain what ethernet applications you have in mind, but remote monitoring, reporting, and control applications need very little flash/RAM.  I'm not even certain what application you have in mind that would need more than 512KB/64KB of flash/RAM.  Anything that needs more than that, you might as well just get an actual Nano or Pico server.  Something that runs embedded linux or full linux.  If people can put a HTTP/FTP server on 32KB flash, 512KB is enormous.

If it doesn't fit your requirements, move on to an ARM chip that does.  It fits other applications requirements. With the Cortex-M chips cost is one of the main factors and an external RAM bus would increase cost and complexity which just overlaps with what other ARM chips already offer.

alm:

--- Quote from: NiHaoMike on October 08, 2010, 05:44:12 am ---64kB seems way too little for a chip that has a 96MHz CPU and Ethernet. It's plenty for an ultra low cost microcontroller. The mbed is not one of those. Especially since Ethernet was never designed for very low power and many network applications are just asking for more memory.

--- End quote ---
I don't see the problem. People are doing TCP/IP with 2k of RAM, why would it be an issue with 64kB? MTU is usually 1500 bytes. Of course you won't be building a high-traffic webserver with this, but since the trend is ethernet connectivity for every single piece of equipment, I think ethernet connectivity on small 32-bit micro's is very useful. You don't need much RAM for basic TCP/IP control / monitoring.

This ARM Cortex M series is intended as a step-up from the 8/16-bit micro's, which are usually well below 64kB of RAM (512bytes - 8kB or so), and obviously not for something like a set-top box. It's not like there isn't enough choice of Cortex A8/A9 and ARM11 chips already, which can support tons of RAM and have much faster performance. But I'm quite sure these cost more than $7/each in 1k qty, especially if you include external RAM. For example, the cheapest Freescale ARM11 is $12 in 100 qty (price breaks don't go higher), plus the price of external RAM. And it's a BGA package, so good luck prototyping in your home lab.

What alternative for the LPC1768 would you suggest with similar price and features, but much more RAM?

NiHaoMike:
My friend Brittany Benzaia does a lot of work on OpenWRT routers and APs and she thinks 8MB is small. Some of those routers are as little as $10 retail.

Back when the mbed was $100, the Gumstix boards and the Beagleboard seemed to offer much more features for just a little higher price. But now that it's $60, the higher end boards are in a totally different category.

GeoffS:
I'm currently using PICs for small projects but  was considering an upgrade to a  Beagleboard.
I still like the idea of being able to run Linux but at less than half the prices of the Beagleboard, it may be worth getting an mbed just to play around - and hopefully learn something.

Navigation

[0] Message Index

[#] Next page

[*] Previous page