general questions regarding ARMs

Hi - I'm fairly certain I'm going to use an ARM in a project I'm
working on. I have a good deal of experience with Atmel AVRs, but I
have never used an ARM before. So I was wondering if you all could
answer a couple basic questions regarding ARMs:

1. programming: My understanding of programming an ARM is that you do
it with a JTAG cable. I was looking at this one, specifically:
http://olimex.com/dev/arm-jtag.html as it is fairly inexpensive. Is
this a good plan? Bad plan? I've also heard of boot-loading. Is this
possible on Atmel ARMs? if it is, does this only temporarily load code
into the chip, or permanently load it in the flash?

2. boot process: when an AVR turns on it begins by executing the first
line of code in the flash - the reset interrupt. Is this how ARMs work?
I noticed that the ARMs that I was looking at can only access their
flash in a single cycle at about half the clock speed - so how would
executing code work for this? I mean how would it run at double that
speed if it couldn't access the code? Does all code get loaded into the
RAM and executed there?

3. operating systems: in my experience with AVRs I've never had an
operating system running onboard. Is this what is done on ARMs
generally? I've noticed that there is ARM Linux - could that run on a
55Mhz Atmel ARM based off of a ARM7TDMI with 64KB of memory and 256KB
of flash? Would this even make sense?

4. DMA: the chip I'm using boasts about its Peripheral DMA Controller
(PDC). It says that it greatly reduces the overhead on the processor.
But reading about it, I am having trouble understanding how DMA differs
from no DMA.

Sorry for asking so many questions - I'm just very new to the ARM
world. Thanks!

-Michael J. Noone

.

Relevant Pages

  • Re: general questions regarding ARMs
    ... > Hi - I'm fairly certain I'm going to use an ARM in a project I'm ... headache because they usually do not provide direct download into flash ... when an AVR turns on it begins by executing the first ... DMA: the chip I'm using boasts about its Peripheral DMA Controller ...
    (comp.arch.embedded)
  • Re: general questions regarding ARMs
    ... > Hi - I'm fairly certain I'm going to use an ARM in a project I'm ... programming: My understanding of programming an ARM is that you do ... > line of code in the flash - the reset interrupt. ... DMA: the chip I'm using boasts about its Peripheral DMA Controller ...
    (comp.arch.embedded)
  • Re: general questions regarding ARMs
    ... > Hi - I'm fairly certain I'm going to use an ARM in a project I'm ... when an AVR turns on it begins by executing the first ... > line of code in the flash - the reset interrupt. ... DMA: the chip I'm using boasts about its Peripheral DMA Controller ...
    (comp.arch.embedded)
  • Re: A couple basic questions regarding ARMs and DSPs
    ... > Hi - I just have a couple pretty simple questions regarding ARMs and DSPs. ... > First of all - when researching options that go beyond the power of AVRs ... > exactly to move code onto the ARM. ... crossworks - commerical ide + gcc ...
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  • Re: A couple basic questions regarding ARMs and DSPs
    ... >> AVRs I've run into DSPs alot. ... >> have to spend too horridly much - so my current plan is to use GNU ARM ... > Some further research has led me to find that it seems some Philips ...
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