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Which microcontroller do I need?

I'm trying to select a microcontroller for an application, and having little luck sifting through the masses of information on the web.

I need:

1) Two async serial ports, capable of running at 9600 BPS. I'd greatly prefer this to be in hardware; bit-banging is too much work, and hard to do in realtime with other things going on. RS-232 drivers are not necessary, but the ability to accept inverted CMOS (1=0V, 0=+2.6V) levels is. 2) Ethernet, with TCP/IP stack provided. A web server isn't necessary, but I'll use it if it's there. 3) Reasonably inexpensive prototype board. This is a ham radio project, and I intend to publish it so that other hams can use it. 4) The ability to develop on Mac OS X, or at least Linux. I refuse to run Windows unless there is absolutely no other option. 5) Open source development tools. I can deal with C, and assembler doesn't faze me; I'd rather not do BASIC.

I don't need:

1) Bells and whistles on the prototype board. No LCD displays, buttons, optoisolators, or any other such. 2) A big, hairy realtime OS. The application's job is to monitor traffic going from one serial port to another, interpret it, and make the contents available via Ethernet, and to accept commands and insert them in the serial datastream going the other way. A nice, small kernel, OTOH, would probably be useful.

I don't care about:

1) Architecture wars. I have no investment in any microcontroller architecture, so I'm free to select the best (or only) one to do the job. 2) I/O pins beyond Ethernet and async. 3) Programming methods, as long as I can plug it into my Mac. This means USB, practically speaking, although an Ethernet-bootstrappable prototype board will also work. 4) Whether programming is accomplished on the prototype board or via a separate programmer.

Thanks in advance for any help you can provide.

Reply to
Jay Maynard
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Freescale M5223x and the M52235EVB dev board. I'm using a GNU toolchain¹ under Linux. Haven't tried MacOSX. Unfortunately there are no free drivers available for the USB FLASH programmer that I know of.

Petter

¹)
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Reply to
Petter Gustad

That looks like a very good choice. Why the M52235EVB, though, instead of the M52233DEMO? I don't need the 235's crypto module, and the M52233DEMO is a third the cost. I'm not above soldering to the second USART pins directly; I'll have to do some soldering anyway to get the signals in and out without using the RS232 driver on the first port, as it is.

Reply to
Jay Maynard

I don't think the DEMO board includes the USB programmer/debug interface. However, I'm a little uncertain since I only have the EVB and not the DEMO. Check with your dealer or on the Freescale site for more info.

Also check out the Freescale forum at URL:

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Petter

--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
Reply to
Petter Gustad

As simple as that:

  1. Get an old PC from junk yard. It has everything you need.
  2. Install whatever software.
  3. Enjoy.

VLV

Jay Maynard wrote:

Reply to
Vladimir Vassilevsky

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is a possibility. Follow the links at the bottom of the page for info on GCC ports, and example projects using FreeRTOS and the (also free) uIP TCP/IP stack.

Got a couple of buttons on it, tho. '-)

Reply to
Rich Webb

Hm. Wonder how you program the board's micro, then?

URL:

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I did, and it raises a question: Based on your experience with your sample code, am I going to get in trouble distributing the complete code, ready to build, if I start from your example? There was a lot of wrangling about it on the forum...

Reply to
Jay Maynard

I would suggest that you consider the Atmel ARM CPU, AT91SAM7X256 or ...X512. I believe it suits all of your requirements and they offer a development board with little in the way of "bells and whistles". There are also many others with similar development boards, some for less money such as from Olimex...

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Their SAM7X256 board does come with a tiny color LCD, but it costs about half what the Atmel module does so could you just cover the LCD with tape and ignore it?

For software you can find excellent open source tools from

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The code to drive the Ethernet port can be found at a number of sources such as RTOS or other real time OS. Or you should be able to use the code available on the Ethernut project which was set up for needs just like yours. Perhaps you should check them out since there is also hardware available.

Another choice would be the Luminary Micro Cortex M3 version of the ARM processor. They have an LM3S6xxx line that includes Ethernet with an eval board which is only $80 including eval tools code size limited to 32 kB. It comes with sample code, but otherwise I don't think there is a large base of software available yet. One of the real time OS is available for it though. The eval board is nice and small, but I think it will also require that piece of tape to cover the OLED display.

While checking out the Luminary CM3 I found that contrary to what one of the frequent posters here will tell you, Luminary *does* have in their road map a device with *both* CAN and Ethernet. Right now you can get either CAN (LM3S92xx) or Ethernet (LM3S96xx) periperhals. The LM3S98xx will have *both* usable at the same time! Not that this is relevant to your needs, but I just found that I was being misled.

Reply to
rickman

The LM3S6965 board looks nice, and for $80, I can't complain. My aversion to the built-in displays was that they tend to drive up the price, but all I'm aiming for is less than $100. If it's there and doesn't drive up the cost, I'll happily use it.

All of the ARM systems seem to use the same JTAG interface. Is there a JTAG adapter that can be used from Linux and doesn't require a parallel port? If I'm going to use Linux (which seems likely; nobody does OS X or provides fully open-source versions of ther software that can be ported, it appears), it'll be from a virtual machine on my Mac, and while I can connect USB devices to it, I can't do that with parallel-port devices.

I'm also impressed enough with FreeRTOS that I'll probably use that. It seems to be able to deal with interrupt-driven I/O on the LM3S6965 for both Ethernet and serial, and that will make programming a lot easier. It also seems to be completely redistributable, unlike the Freescale stuff.

Reply to
Jay Maynard

Look at Netburner. THey've got some $99 systems that should fit the bill.

gm

Reply to
GMM50

Jay Maynard pisze:

[CUT] Have a look at at Zilog's F91. Has most of the stuff you have mentioned. Although dev tools are Win only, but I've run them under linux with Win emulator.

Maciek.

Reply to
Maciej Sawicki

[...]

Have a look at

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They use an AVR ATmega128 and a RTL8019 for Ethernet. The ATmega128 has two serial ports - the second one is on the pin headers. There is a Gcc for AVR, and there is a small kernel with IP stack for that board. Programming the AVR through the ISP interface (SPI plus

-RESET) is easy - it took me half a day to write my own programmer, so you can easily build your own if you don't find mac programmers. Look at:

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If you want to bring your BOM and hw costs down to the minimum, I'd choose an ATmega644P and connect a Microchip ENC28J60 Ethernet MAC/PHY via SPI. Both chips are also available in DIP packages (40 and 28 pins), so it's easy to work with. You don't need a full IP stack just for sending IP Multicasts or broadcasts and can get along just with the internal memory (64k program flash, 4k ram, 2k data eeprom).

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(sorry, German only, but you should be able to find the schematics. They use an Mega32, which has only one UART, but the changes for the Mega644P (the P is imPortant!!!!) should be minimal.

Mit freundlichen Grüßen

Frank-Christian Krügel

Reply to
Frank-Christian Kruegel

Sounds like you need a low-cost-module.

So look thru the main suppliers for their lowest price, ready to go modules.

One thing to watch, will be if the 'Demo' SW versions have a limit you will bump into,

Atmel have something for the AVR32, you could also look at Rabbit.

Zilog have just released a ZDOTs module, that they claim has Full Tcp/IP and operating system.

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Module is tiny, appx business card in area, with 0.1" expansion headers - think of it as Jumbo DIP :)

I have not seen a price indication yet om the ZDot module.

Their Z80 series have a LOT of legacy Sw, and will be known by your audience. So I'd favour "mature and proven" over "new kid on the block".

-jg

Reply to
Jim Granville

"The product page says:

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One BDM (Background Debug Mode) "wiggler" cable" and "The integrated BDM allow easy application development and debugging". so it seems like it's integrated on the board. If you click on the photo you can see a chip labeled "P&E BDM USB":

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It's not my code (but another more experienced M5223x enthusiast also named Petter). The issues are related to the distribution of the Interniche code. To me it seems like you have to provide it in such a way that whoever downloads the code has to click and agree to the license prior to downloading.

Petter

--
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
Reply to
Petter Gustad

Arm7 or arm9 chip olimex make some cheap boards sparkfun sell them

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have a look at lpc,cirrus ,sam7 , st and tms ranges

most can be programmed via serial bootlader or jtag. Can get parallel port or fairly cheap usb jtag devices.

lpctools.com sell a range of boards based on the nxp(philips) arm7 and arm9 chips

arm gcc ports are available for linux , mac osx and windows. rowley make an ide + gcc with commerical support for windows and linux.

futurlec.com sell some very cheap dev boards can take a while to ship

codesourcery tools usually have support for the latest chips before the others but are not always as easy to use. lite versions are freely available

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Some companies only provide examples for the commerical windows based tool chains

Atmel make the avr32 have a demo board for US$69

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they supply prebuilt tools here
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Can use the same programmer as the avr series including usb isp tool (approx $30) works from both linux and osx.

gumstix.org make some nice tiny little boards that run linux very easy to get up and running on linux. from 200 - 600MHz 32MB ram and up to 32MB flash.

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The netburner coldfire modules are nice.

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They only provide windows tools. Linux tools are available, I haven't been able to get them to build on osx.

The blackfin stamp boards also have a good feature set

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Can buy them from digikey for approx US$220

Another similar blackfin board but for voip

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Alex

Reply to
Alex Gibson

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