Teeny, Tiny, Microcontrolers.

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Hi, I have been searching around now for a couple of days for a suitable micro controler for a project i'm thinking about giving a go. What I was looking for is something very small (at most 10mm X 10mm X 3mm), with an internal oscilator to cut down on parts, and some sort of EEPROM or flash memory available when the device is runnig for storing data (I need at least 1k bytes here, but would prefer if I could get 1Mbytes or more).

Now I have found a couple of possible candidates, one from national, the COP8 line, whihc can meet the size and memory requirements, but have no internal oscilator so isn't realy any good as I will be quite pushed for sapce in this project I think. also, I found a device from ATMEL, the tiny 26L which meets all of the requirements appart form the memory (but they also sell a 2k bit EEPROM in a SOT23 package (3x3mm) which would help with that).

What I was wondering is if anyone here who is more familiar with these sorts of devices could point me in the direction of a similarly small device which will meet or surpass all of my requirements with out using any external components. If you could do that I would much apreciate it.

Andrew.

PS, one thing I forgot to put in is that the device will need to run from battery (~3V) and hence draw very little current.
 
bigparsnip said:
Hi, I have been searching around now for a couple of days for a suitable micro controler for a project i'm thinking about giving a go. What I was looking for is something very small (at most 10mm X 10mm X 3mm), with an internal oscilator to cut down on parts, and some sort of EEPROM or flash memory available when the device is runnig for storing data (I need at least 1k bytes here, but would prefer if I could get 1Mbytes or more).

Now I have found a couple of possible candidates, one from national, the COP8 line, whihc can meet the size and memory requirements, but have no internal oscilator so isn't realy any good as I will be quite pushed for sapce in this project I think. also, I found a device from ATMEL, the tiny 26L which meets all of the requirements appart form the memory (but they also sell a 2k bit EEPROM in a SOT23 package (3x3mm) which would help with that).

What I was wondering is if anyone here who is more familiar with these sorts of devices could point me in the direction of a similarly small device which will meet or surpass all of my requirements with out using any external components. If you could do that I would much apreciate it.

Andrew.

PS, one thing I forgot to put in is that the device will need to run from battery (~3V) and hence draw very little current.

The Cygnal parts don't need an external crystal (even for serial communication) and some versions are really small (3 mm x 3 mm). Not the very lowest power consumption though. http://www.cygnal.com/

The TI MSP430 is a really good choice for low power operation. http://focus.ti.com/analog/docs/analogprodhome.tsp?templateId=5246&familyId=342

Phil
 
Charles, I have had a quick look at the data sheet for the PIC16F72, but although it mentions setable options for the oscilators, I can't find anything there that mentions the inclusion of a master clock which the device can run from. So I take it that I would need an external ocsilator or crystal (I know on the other PIC devices there are settings to alter the timer oscilators, so I am assuming that that is what the data sheet was refering to) to get this device up and running? Which would be a shame if it is, as I realy would rather have an onboard unit.

As for the others, thanks very much but it looks like I am going to have to settle for one of the ATMEL, or cygnal (thanks haldor) processors, allong with some external flash memory for the time being.

For those of you wondering what this was supposed to be for, I was looking at trying to make a very small data logger (and possibly in the future fit it out with bluetooth wireless comunication, but as of yet, the most prommising product I have found to implement that - from national - has not been compleeted yet) that ran off bateries. Also, if this did work out, I was considering the posibility of producing a very small (pre) amplifier controler, which would be able to fit onto the back of a VFD display, and control a number of devices assuming they all had similarly small control modules tucked away in them somewhere.

But thnks again, and if anone else out there spots this and knows an more then please let me know, as I haven't quite given up searching yet.

Andrew.
 
bigparsnip said:
(and possibly in the future fit it out with bluetooth wireless comunication
Bluetooth is really expensive to implement. It starts from 10 kUSD and can cost more. This is if you want to put the BT logo on your product!

Our company has investigated the possibilities and come to the conclusion that this is only suitable for mass market or non-low cost. :down:

NOTE: This is only if you want to sell the product. If you only want to fool around it costs you only the BT-modules.
 
Hi Bocka, do you actualy have any experience using the ATMEL range?

I was wondering if the only real difference between the MEGA range and their Tiny range was the number of instructions each chip has (the MEGA being around 130 I believe and the tiny bing about 90)?

If I did go with one of the AVR processors, I think at the moment, I would either chose the ATtiny26L, or the ATMega162V, both of which are available in the MLF package which is only 7 X 7mm, and will operate at low voltages (in fact having looked, I think the mega162 states that it will only consume around 0.6mA when opperating at 1MHz from a 3V supply).

Andrew.
 
Hi Andrew,

the large ones also have an ADC, 2 serial ports, a JTAG-Interface. The MEGA162L is an excellent choice, you should simply get some samples from your distri.

I haven't used the MLF package yet. I would use the newer MEGA162L because of the better availability in the future. Some of the old AVRs are not recommended for new designs...

Bocka
 
Hi, thanks for that Till, I had a quick look and it would appear as though I have found the most suitable device so far, the PIC16FL628A. It has most of the things that I need, and from what I have looket at the lowest power consumption of any of the suitable devices so far (at the most 1/2 a milliamp under the condidtions I would be using it), so thanks again for pointing me towards them.

jackinnj, as far as soldering them goes, I wouldn't even dare try by myself. What I was planing was to prototype using one of the same types of devices but in a larger DIP package, then when I was happy with the design, get some boards made up and let whoever makes them mount the components for me (I'm scared by SOP soldering, so the idea of tring one of those MLF, or QFN packages is actualy quite scary:cannotbe: ).
 
I take it you are using one of the larger package types in your project right? Is it easy to get software and programing tools for this chip, as I assume you did it all your self, so you should have a little experience with it. Also, do you know if it is posible to program this chip in circuit, or would I have to keep removing the chip during prototyping, and reprograming it seperatley?
 
bigparsnip said:
I was wondering if the only real difference between the MEGA range and their Tiny range was the number of instructions each chip has (the MEGA being around 130 I believe and the tiny bing about 90)?

Andrew.

Hi,

I am using the Atmel AVR’s for 5 years now and the are great to develop with. I am using these for industrial temperature and motor controllers. For low power they have a wealth of low power options and have build-in uart options, great for data loggers.

For a data logger I would recommend to hook up an external SRAM and use the internal SRAM for scrap memory and stack use.

Concerning the Tiny range: These are very popular at the moment and Atmel will continue these one’s and will come with new ones. The current Tinies are all manufactured with the new .35 micron process. I just contacted my repri last week about this. I am intending to use the new ATtiny26L for a small but accurate temperature controller. (these cost 1$ / 100).

Concerning the build in AD converter. Look at the various AVR parts. They have different options. Not all have a differential input option and some have a build in x20 amplifier, great for RTD temperature controllers.

For ISP ( In system Serial Programming) I strongly recommend to spend $50 for their Serial ISP. You can find on the WEB various DIY programmers but these do not support the newer devices, and/or these do not support all fuse options. Contact your local repri and ask for a data CDRom and dig through the various datasheets for the one that suits you most.

Suc6 :)
 
bigparsnip said:
Charles, I have had a quick look at the data sheet for the PIC16F72, but although it mentions setable options for the oscilators, I can't find anything there that mentions the inclusion of a master clock which the device can run from. So I take it that I would need an external ocsilator or crystal (I know on the other PIC devices there are settings to alter the timer oscilators, so I am assuming that that is what the data sheet was refering to) to get this device up and running? Which would be a shame if it is, as I realy would rather have an onboard unit.

Andrew.

Hello Andrew -

You're right, my mistake. We use several different PICs and I got confused. There is no internal RC oscillator on the 16F72. Another poster suggested the 16F628, which is also now available in the small QFN package. So *this* one should meet all your requirements.

:)

We've prototyped with the QFN package. Of course you need to have a PCB, as you can't do anything else. But it's not all *that* bad to solder by hand. All of the leads are accessible from the side of the package. If you try to do this, I strongly recommend a Metcal soldering iron, as these are the only ones that can apply the full power at the end of a fine tip. They're expensive new, but are available on e-Bay for $100 to $150.

Good luck,
Charles Hansen
 
Charles Hansen said:
We've prototyped with the QFN package. Of course you need to have a PCB, as you can't do anything else. But it's not all *that* bad to solder by hand. All of the leads are accessible from the side of the package. If you try to do this, I strongly recommend a Metcal soldering iron, as these are the only ones that can apply the full power at the end of a fine tip. They're expensive new, but are available on e-Bay for $100 to $150.

Good luck,
Charles Hansen

No need for an expensive soldering tool. Use a wide flat tip. First fix the part in place with a few blobs of solder. Then use sufficient solder to solder one side at once. Owe now all pins are connected together :eek: Now remove the excessive solder with SoderWick. This way there is just enough solder left between the pins and the PCB traces to make reliable contact. Soldering 0.5 mm pitch TQFP’s parts is a snap this way. Be careful not to overheat the part.


;)
 
Hi, just thought I would give you guys a little update just in case anyone else was following this thread.

After quite a bit more searching, I have found what I consider to be the three best chips for my task, whihc I will lis below with a brief description.

ATMEL AVR ATtiny26L - reasonably low power chip, whihc comes in a very small package, and has a good instruction set, the only drawbacks are the limited instruction space (1000 opperations), and the fact it has double the current consumption of the microchip device (althjough, it may run the code in less than half the time as it has a lot more instructions than the PIC device).

ATMEL AVR ATmega169V - Same power consumption as the tiny, but more memory, I/o pins and a few more instructions to use. The main drawbacks with this one are that it is a bit porky (a whole 9 X 9 mm) and probably cost a lot more than the tiny. But, this device would make the codding a lot simpler.

Microchip PIC16F7X7 - a very low power device, with its own on board, speed selectable oscilator, and plenty of memory and I/O lines. The only small problem is that it has no on board EEPROM, and the instruction set is very limited compared to the AVR devices (oh, and they aren't going to be supplying them until October).

So, I think that if I do get to stay on with this project now, I will be going with either the tiny26 or the PIC16F7X7 depending on how quickly I can run the required code on each device, and therefore, how much power each would consume.

Hope this might be helpful for someone out there, and thanks again for all the help you guys gave me earlier on with this.

Andrew.
 
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