Info pls: About ARM processors?

[louarnold]

I have been reading about ARM processors. Here are a few questions I have:

1) Is ARM really an intellectual property company that has designs for micro controllers?

2) And their designs are licensed to semiconductor firms that produce the processors?

3) They have something called "System IP" that seems to refer to inter support device (memory, etc) communications. Does IP refer to Internet Protocol or Intellectual Property? or to something else? Nobody seems to make this clear.

4) Do individual processor types interface to common support chips - memory, IO, DSP, communications, graphic display, sensors, etc? Or are these devices built into the semiconductor chip?

Lou.

 

[millwood]

1) yes.

2) yes.

3) likely intellectual property but impossible to know for sure without having the context.

4) yes - the answer isn't arm dependent. 2nd answer to the 2nd part is "it depends".

 

[bobsanjose]

I have been reading about ARM processors. Here are a few questions I have:

1) Is ARM really an intellectual property company that has designs for micro controllers?
Lou.

ARM designs the core and some peripherals but they do not design microcontrollers. Productions is up to the lisencees

2) And their designs are licensed to semiconductor firms that produce the processors?
Lou.

The semiconductor companies produce microcontrollers with the Cortex-M and mostly processors with the Cortex-A

3) They have something called "System IP" that seems to refer to inter support device (memory, etc) communications. Does IP refer to Internet Protocol or Intellectual Property? or to something else? Nobody seems to make this clear.
Intellectual property and in the content it is clear. ARM has nothing to do with IP as in TCP/IP

4) Do individual processor types interface to common support chips - memory, IO, DSP, communications, graphic display, sensors, etc? Or are these devices built into the semiconductor chip?
Lou.

Both possible. The MCUs based on Cortex-M usually have memories build in and some have external bus interfaces. The Cortex-A usually has just cache memory internal no program memory, that is external. As for DSP, graphic... both versions exist, some internal and most external.

Lou.

hth, Bob
more in ARM based devices at **broken link removed**

 

[millwood]

the "core" portion of the programming is really transparent to a high level language programmer: the portion of your C code that relates to the "core" will be identical, were it on a ARM chip or a non-ARM chip, or even from one flavor of ARM chip to another flavor of ARM chip.

that differs from one "ARM" chip to another is the way you (or the "core") interact with the peripherals. for a reasonably complicated program, that device specific portion of the code may be 10 - 20% but it is where money is made.

a good programmer will try to hide away the device specific code, in order to maximize the code's portability. that's where the most money is - the system architect for a project.

most embedded firms will already have a large code base that deals with the non-device specific stuff. all you need is to take a new piece of hardware, abstract it in a way that it talks to the existing code base. That's where understanding the specific device and prior experience comes in.