question about ARM

Opcodes at 0x0A paces? I've heard of this duel-use technology. Best regards, Spehro Pefhany

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Spehro Pefhany
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Hello group,

I'm planning to learn micro-controller programming and will appreciate it if you somebody could help me to decide on a platform to start.

I have chose ARM series but currently there are two different models as:

1) LM3S811 2) MCB2300

1) which one would be a better choice for a newbie?

2) which one is better for RTOS? 3) which one has better documentation and samples that I can learn from?

Regards.

Reply to
ramsin

Although both ARM devices, these are completely different cores. The 2300 being ARM7 based, and the LM3S811 being Cortex-M3 based.

The MCB2300 has Ethernet, whereas LM3S811 does not. If you go for the Cortex M3 then why not go for an LM3S8962, or LM3S6965, as these also have built in Ethernet (including built in PHY).

You cannot answer that question without putting in the context of an application - I know this is a learning exercise for you so you don't have an end application.

The Cotex-M3 is designed from the ground up to be an embedded core and includes features that make it very easy to support using an RTOS. The ARM7 requires a slightly more complex RTOS implementation, but it works just fine too.

There is plenty of documentation and tools for both. You can find many examples on the net for the LPC2368/LPC2378, while Luminary Micro themselves provide a really good set of drivers and examples for the LM3Sxxxx parts.

The Cortex-M3 is simpler to get up and running, so if you are new to this then maybe that would be the best choice? Again without putting it into context of a real application it is difficult to say which.

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Richard.
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Reply to
FreeRTOS.org

ramsin ha scritto:

I agree with Richard, there isn't an absolute best choice. The LM3S811 has a Cortex-M3 core that is embedded optimized, so, eventually, I think that will see more of them in the future. The ARM7TDMI core is much older and maybe, you will find more documentation now, but I think that this is going to change in the future.

Both of them are equally usable by an RTOS. Maybe at the current moment there are more RTOSes supporting Philips than Luminary processors, but things are changing rapidly, and if you are doing this for learning purposes maybe you should spend time on the newer one (Luminary).

Maybe Philips NXP processors have better diffusion, but Luminary is doing a great job in supplying drivers and documentation, so, final decision is up to you, without any context information is not possible to say which is the best.

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Reply to
Francesco Sacchi

If you haven't used a micro-controller before you will probably find the ARM rather overwhelming. It might be best to start with a simpler device.

Leon

Reply to
Leon

I thought it was just a Thumb-only ARM. What features did they add that you've found useful for RTOS support?

Reply to
Eric Smith

You are correct that it is essentially a thumb 2 instruction set. It was designed not to need underlying ARM instructions

w..

Reply to
Walter Banks

I also have the same situation, looking forward somebody's suggestion.

Reply to
Electronic Elephant

hello:

as:

excellent choice.

  1. ARM is, i think, the most popular CPU core right now, used in iPod and in many mobile phones.

  1. ARM has a very interesting design philosophy. its RISC and also has conditional execution of ALL instructions. it also has a Thumb mode. these are unique to the ARM.

  2. its 32-bit in a small, inexpensive package so that you can run uCLinux on it easily.

so, if you learn ARM, you learn a new architecture and can also install Linux on your simple MCU board. you learn Linux also.

this is the future and you will be prepared for the future! have fun!

Aaron

Reply to
adsouzp

Additional even the interrupts run Thumb2 code and they look like normal functions for code generation. Interrupts are nestable. For other ARM devices interrupts run ARM code and need special games to nest (switching execution modes and stacks). So Cortex-M series (there is also an M1) are more like regular single-stack micros.

Peter

Reply to
Peter Dickerson

More like, but not actually single stack. There are still two stacks.

-- Regards, Richard.

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FreeRTOS.org

Integrated interrupt controller, integrated SysTick, interrupt system that makes nesting very simple, PendSV mechanism to make nesting even simpler, fast interrupt entry - all these things make implementation and portability between vendors much simpler. Its a whole lot more than a Thumb only ARM7, if that is what you were implying.

-- Regards, Richard.

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FreeRTOS.org

Well that depends who you ask :o) Renesas will claim to sell more, and 8051 in all its shapes and forms as a collective still sells in huge numbers, then you have the blob micros that get used in things like very low cost toys that sell by the bucket full.

This does not apply to the Cortex-M3, which does not have ARM mode but Thumb-2.

Thumb mode is unique to ARM as it defines ARM instructions, but the idea of having a duel instruction set is not. I think MIPS can also run MIPS16, a

16bit version of the instruction set.

-- Regards, Richard.

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Reply to
FreeRTOS.org

So Thumb and ARM fight for control. Anybody know who won. Clearly Thumb for the Cortex-M series.

Peter

Reply to
Peter Dickerson

"adsouzp" skrev i meddelandet news:T6idnfCDTrXZ2qfVnZ2dnUVZ snipped-for-privacy@giganews.com...

If you want to run (uC)Linux, you will have to use external memory The linux-2.6.25 is close to 3,5 MB on an ARM... You are likely to want to to have SDRAM, so your "small, inexpensive" package becomes 150-200 pins. Then it does not make a lot of sense to go ARM7 nor Cortex-M/R families. Why waste time on uCLinux when you can get the real thing.

The AT91SAM9XE will give you an ARM running up to 200 MIPS in TQFP. Pin compatible AT91SAM9G20 will provide 400 MIPS, but will require external memory.

The MMU in the ARM926 core makes it possible to store several applications in the internal flash, and allows you to link both applications to the same address, while you store them at different addresses. This solves a significant problem, if you do field upgrade.

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Ulf Samuelsson
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Ulf Samuelsson

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