DualCore has introduced a monster - two ARMs, two 10/100 Ethernet MACs, and a whole lot more on one microcontroller:
Not a bad start for a startup, huh?
Regards,
Bill Giovino Executive Editor
But at "below $20" it sounds expensive.
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
True, and it also starts to call for a different category than "Microcontroller", with limited on-chip memory it probably is more correctly an "Embedded Microprocessor" - or a ROM-less Microcontroller
-jg
What is it then that defines something as a microcontroller rather than a microprocessor? Does it have to have on-chip memory for that? My Sharp ARM7 has no on-board flash but has 8K of on-board RAM. Does that make it a microprocessor?
A new Troll!
To me the fact that a CPU is combined with peripherals makes it a microcontroller, but this is my private opinion. There are no clear boundaries and a discussion is probably a waste of time.
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Years ago, it was more clearly delineated: There was the Microprocessor (8080 etc) and the Microcontroller (8748 et al), and the Microcontroller was "self contained" - it was a one-chip control solution. There was not a lot of code memory, but it WAS on chip.
These days, someone in marketing is more likely to decide (on a whim)
- so we get a growing number of devices that are no longer single chip solutions, but still get called Microcontrollers....
Or, companies marketing dept's try and get all the buzz-words they can, in case they miss one ... ? :)
For example, I see Atmel call the AVR32 many different things : Microprocessor and Digital Signal Controller and MCU/DSP and SoC and Microcontroller ..... - A truly google-friendly core ?! ;)
-jg
I'll admit it looks like something that may have been trolled before but I am interested to know what the difference is and if there is a definition, even if out of date.
If wasting time were not allowed then considerable areas of usenet would have to be should down :-)
Zilog gives a good example/lead of what is a Processor, and what is a Microcontroller. They make both, and have done for years. Their delineation is not based on peripherals, but on-chip CODE memory.
-jg
That's I've been tought: CPU + peripherals (even ROM) =>
microcontroller. But with this definitions the AMD Opteron with RAM interface is a microcontrollers too.
-- 42Bastian Do not email to bastian42@yahoo.com, it's a spam-only account :-) Use @monlynx.de instead !
I think any definition should be rule based. The rules below are prioritized, and once a decision is made, there is no need to parse lower priority rules.
Rule 1) Anything running late versions of Windows (CE does not count here) is not a microcontroller I am going to ignore all comment about Geode... Rule 2) Anything without internal code memory (cache does not count here) is not a microcontroller Rule 3) Anything with a serial communication channel, is a microcontroller Rule 4) Anything without minimum 1 timer providing a periodic interrupt is not a microcontroller Rule 5) Anything without minimum 1 programmable I/O pin is not a microcontroller Rule 6) Anyting REQUIRING a companion chip, is not a microcontroller ... Rule n) It is a microcontroller
If I follow these rules above (which I just invented), then the chips I can think of which I intuitively think are microcontrollers will be classified as microcontrollers.
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Your Rule 6 would exclude all external CODE devices, as code storage is certainly "a required companion chip" ! ( this is the scheme Zilog uses, they call external code == Microprocessor, self-contained == Microcontroller )
-jg
If you cannot execute code from internal memory, then you are sorted out already by rule 2.
Having internal memory is a must, but it is not enough,according to my gut feeling If you put 2 MByte of flash on a Pentium/MMX chip, it would still not be a microcontroller
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Nice idea.
Maybe refine this: "...internal code memory (RO or RW) ..." Else sam9261 is no microcontroller.
I should send these to my old uC teacher :-))
-- 42Bastian Do not email to bastian42@yahoo.com, it's a spam-only account :-) Use @monlynx.de instead !
Yes, it was not inteded to limit to non volatile memory. But this clarifies it.
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Better even refine to "which is not available with code memory.." Else the 80C31X2, the 80552 and 80C152 I have been programming the past year also are NOT microcontrollers according to you....
regards, Hans Bus
This is a pretty arbitrary, and isn't really necessary.
I disagree. There are plenty of microcontrollers that have no internal code memory. Consider, as an example, the MPC561, which is a microcontroller based around the PPC core. The MPC563 device is identical, except that it has on-chip flash. Does that make the MPC563 a microcontroller and the MPC561 a microprocessor? This rule would be better as "anything with internal code or data memory is a microcontroller".
I'd say it is difficult to formulate an exact rule, but the main point is that if the device has on-chip peripherals, it is a microcontroller.
This is fair enough. A microcontroller should either run from internal memories, or have glueless (or almost glueless) buses for external memories. You might need the occasional inverter or address latch, but you should not need external address decoding or bus control.
What's needed are a few well-known examples of borderline cases for testing the rules.
You are right, but I think it is better to move up the rule about serial ports and maybe make anything with a timer a microcontroller. Dont think that a part with just I/O, no timer/serial and ext memory qualifies but onchip memory and I/O should certainly qualify.
Rule 1) Anything running late versions of Windows (CE does not count here) is not a microcontroller I am going to ignore all comment about Geode... Rule 2) Anything with a serial communication channel, is a microcontroller Rule 3) Anything with minimum 1 timer capable of providing a periodic interrupt is a microcontroller Rule 4) Anything without internal code memory (cache does not count here) is not a microcontroller Rule 5) Anything without minimum 1 programmable I/O pin is not a microcontroller Rule 6) Anyting REQUIRING a "companion" chip, is not a microcontroller Clarification: A companion chip is defined as a chip which if integrated with a microprocessor would make the microprocessor a microcontroller Exception: A pure memory is not a "companion" chip. ... Rule n) It is a microcontroller
As mentioned previously, parse rules until there is a decision and do not parse any further.
-- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Yes. So here's my approach:
It's a microcontroller only if
1) it's a "micro", i.e. a programmable CPU of some sort, which comes as a single part.2) it's a "controller", i.e. it can actually control *something*: it has at least one input, and reacts to it on at least one output in a programmable way. Data bus doesn't count as I/O, here.
3) It works all by itself, with *no* extra parts except for a very few exceptions, such as power supply and an external oscillator/quartz.The only point really open to discussion is whether code memory goes on the exception list of necessary extra parts, or not. Here's where the idea of a "family of microcontrollers" becomes useful. A candidate that fails to have internal code memory can still be counted as a microcontroller if it's just one member of a larger family including devices that really are microcontrollers.
This should be limited to closely related chips. One might want to require that there's a fully drop-in replacement for the candidate chip that has all the same features, except the need for external code memory.
-- Hans-Bernhard Broeker (broeker@physik.rwth-aachen.de) Even if all the snow were burnt, ashes would remain.
PPCs have a decrementer, which acts as timer. I am not sure, but I strongly believe you can find it as well in "desktop" PPCs.
-- 42Bastian Do not email to bastian42@yahoo.com, it's a spam-only account :-) Use @monlynx.de instead !
Modern x86 devices have all sorts of internal timers and counters as well, and they don't count as microcontrollers by any standards.
I think identifying microcontrollers and microprocessors is a bit like identifying spam and ham - you have some rules that contribute points one way or the other, with your final decision based on a total score. A single fixed timer gives a little score, but several flexible timers (especially with dedicated pins) gives a much bigger score.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.