Teeny, Tiny, Microcontrolers.

[jackinnj]

good luck soldering those babies -- for the "tiny outline" smt devices you are going to need a stainless steel film mask made from your Gerber files on which to apply the solder paste -- the tiny outline devices, bga types are best left for machine placement.

[till]

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

bigparsnip,

The Pic devices with internal oscillator are 16F6xx and 12F6xx. They are about 4Mhz or software switchable to 37kHz.
smallest package is MLF-S.

[bigparsnip]

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 ).

[till]

16FL628 - thats the chip i also use for my relais volume control on this picture
http://www.diyaudio.com/forums/showt...996#post219996

[bigparsnip]

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?

[till]

You can ICSP the chip, there are different programming tools from microchip, and free development software. A ICSP programmer is easy to build with about 5€ parts. You need not much more than cable, connectors, 7407, some transistors, and 5+12V power supply for a good ICSP programmer.

http://www.sprut.de/electronic/pic/p...r5/br5_sch.gif

I use DIP, its easyer.

[Pjotr]

Originally posted by bigparsnip

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

[Charles Hansen]

Originally posted by bigparsnip
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

[Pjotr]

Originally posted by Charles Hansen
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 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.

[bigparsnip]

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.