Hello, I'm just a beginner so I have a few questions if u don't mind.
1) I would like to know if AVR micros are a good place to start learning about microcontrollers. Or would you recommend looking at other chips instead like PICs or 8051s?
2) Can AVR chips be programmed in C using the GCC compiler in Linux? Is embedded linux primarily being targetted more for boards (like PC/104) or can it be used on a microcontroller?
3) I was looking at this site :
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at their "Raver" programmer. It is used to program a variety of AVR micros. Is this something I should consider getting to start me off?
4) Can a TCP/IP stack be implimented on microcontrollers like an AVR or something else?
5) Why is it that on a computer we can get over a gigabyte of memory, yet on microcontrollers, mankind is still struggling with a few KB of memory? I know its cost but surely a 1MB stick of ram cannot be that expensive today.
All chips have their advantages and disadvantages. I like the clean architecture of the AVR, and there's plenty of free tools and support available.
Sure.
I haven't seen a port of Linux to the AVR, and I don't expect one since Linux is big and AVRs are small.
That seems like a popular board. I like the Atmel STK500 eval board myself, but I'm happy to do my development under Windows with the Atmel tools.
It's been done, but I believe the stacks ported provide a lot fewer bells and whistles in their API than stacks on larger CPUs. I wouldn't try TCP/IP on an AVR or PIC unless I was under serious cost constraints on a high-volume product.
There are lots of reasons: process constraints, packaging costs, and market needs, to name but three. If there was a serious market need for low-horsepower CPUs with lots of on-board DRAM, I expect there'd be some offerings with that feature mix. Since I don't see any parts like that on the market, I conclude that most applications that need low-end CPUs don't need much memory.
1) Yes, AVRs are Ok, as are the rest.Having someone local to talk to helps in debugging though...
2)Probably,though I'm using PICs exclusively for the past 5-7 years.
3) Dontronics has some really nice stuff and has been a stable company
4)PICs have been used for the past 5 years as 'Webdevices' so TCP/IP can bee easliy done(BTDT).
5)MICROcontrollers are that, micro. NO need for MEGAbytes as a REAL programmer can cut tight code to do the task at hand.I'm still impressed with a 6800 system,still in use today, that only has 8K ROM,1K RAM which implements a 512 channel LAN, true single wirefull duplex,interlaced protocall SCADA system used in the very highest of alarm monitoring ULC AA listed Central Monitoring Station.It not only allow control of 512 alarm panels but has builtin printer,LED display,MMI and full realtime line diagnostics. Not too shabby for an old 8 bit micro !
let me provide you with some answers which reflect my personal opinion and experience:
1) AVR is very good to start. If you want do do bizzare stuff first go for PIC or 8051. (I know I will receive bashing & beating for that ;-) )
-- get the processor manuals form either chip and read them. Have a look at the achitecure and compare.
The AVR for starting purposes is easiest to understand. The 8051 has a very long product history. In fact it was one of the first Microcontrollers as we know now (to abbreviate and be a bit imprecise...) It is worth knowing it and there is a wealth of grown knowledege available on the web.
2)
a)
Yes. google for AVR-GCC.
b)
Certainly not on an 8 bit microcontroller with limited resources.
It's more for the "Ferrrari/Porsche league" of Controllers and processors like Intel 486/Pentium, Motorola Power PC and the 68000 32 bit CPU.
Dontronics has some fine products.
If you need to know anything about the products that is not on the website, ask Don. He's a nice guy and will answer.
There are other Multiprogrammers like the GALEP
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that allow to program a whole variety of devices like flash EPROM, PAL, GAL and all kinds of mocroprocessors with on- chip program memory. Be aware that you will have to invest some money but then you have a multi purpose tool that will pay for itself over time.
Has been done. google for ethernut or check out
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Because it is a different techology. On a microcontroller the RAM and all other functions like timers AD converters UART modules are integrated in one circuit. (Keep it simple...) The RAM is not dynamic but static RAM (SRAM) which is more costly to produce. And: most controller applications do not need so much memory. (Again - this is negotiable...)
Also microcontrollers are used by manufacturers in huge numbers and every cent counts. That is: if a unit only needs 8 kB RAM,- more would be a waste of money. After all products are made to make a profit so cost will have to be kept as low as possible.
If you take your memory stick and connect it to a controller you need additional traces on the board, a bigger board, a connector etc... This ii simply too expensive for high volume products. In contrary: the current development leans toward "systems on chip" or "board on chip (BoC)" for these kind of products.
regards /jan
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rather not. You need to buffer as many packets as are out while waiting for an ACK. With just one buffer, the performance is rather low.
1) reliability. how many hours until a read error occures ? Not just under lab conditions.
2) power draw. you cannot run DRAM or such on a few mA.
3) they are mostly suffient for what the app is intended.
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