I want to use an ARM microcontroller on my graduation thesis. But, because of the high price of an evaluation board and taxes of my country, i can't buy an evaluation board. So I have to make it by myself
It has a complete CPU board with the Atmel AT91R40008 CPU on it, called hcAT91. Full schematic and PCB documentation is available. You will also find a small starter-kit there that would provide you with a power supply and an RS-232 interface.
What exactly do you mean by making it yourself? Do you want just schematics or gerber files? Are you able to make 6 or 8 layers PCB, with 0.3 to 0.4 mm holes and 0.2 mm lines?
What country are you in? I have not heard of 400% tax before.
Atmel ARMs comes in 0.8mm BGA. Probably 6 layers board.
When you design some device with ARM MCU, don't you have to make a board for this? For example, when you are making a MP3 Player, you have to make a board for it!
(Price + Tax + Shipment) costs between $100 and $200. Why do i buy a board $55 instead buying a board $200!!! That's my country
As you said i can't make it by my hand! I have to design it with a PCB Program and give gerber file to a board maker company!
Guys, What is the strange side of making it by myself? Did nobody here make a board before?
Where do the companies learn making ARM evaluation board? Is this secret????
Yes, the question is whether you can find a company in your country to make board with the above specifications.
Country with such high protective tariff may not be able to produce fine-pitch PCB needed for ARMs. That's why they are protecting their local PCB makers in the first place.
Only if you can send it to a local company capable of making it.
Not us (USA), most of us don't make boards anymore. We just farm it out somewhere else on earth.
Not secret, but expensive labors and equipments. To start with, you need a laser drill for holes less than 0.4mm. Not many of us have a laser drill in the garage.
Nothing with more than 2 layers. You'll want at least 4 layers for a 0.8mm BGA (decoupling, ground plane). You can have one made at a printshop, but it's gonna cost you more than USD
200. That's just the board, no components. The reason why commercially available bords are so cheap: economy of scale.
Don't have a clue why people are always talking about BGA package.. at91rm9200 is also available in QFP...though more expensive.
Also many schematics are available for it...for example:
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Only heard from one though making a 2-layer board and having problems with SDRAM...you might be available to have success...but don't expect to route out all periphal signals it can offer...4-layer minimum if you want the fancy stuff as well...but don't know if any free PCB package is capable to do so...
And also...getting at91rm9200 samples isn't an easy task if you can't tell a good reason (o;
If one is dedicated enough it's absolutely feasable to produce multilayer boards at home. I made my own through plating station for this very purpose and sucessfully create 4 and 6 layer boards - see.
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Due to the lack of spare time my project to finish a small oven which is able to follow temperature curves to propperly solder BGAs is not yet finished. However others made this already so again, if one is dedicated and willing enough things like this are feasable.
It's much fun to decide to need a board and have it in your hands 4 -
6 hours later. Where I live (Switzerland) producing a board in 3 working days (not 4 - 6 hours) would generate costs higher than those of the station including all chemicals etc.
However, for a one time project this is impossibly cheaper than buying a board somewhere. In my case espeically the long time it takes to get a board with reasonable costs was the main reason to initiate the project. Getting the experinece and overall have fun doing something like this were also motivating factors.
In short, the process needs thinner base material than usual. Bungard
- a german supplier of board material - does have it, but I figure you also get that in the US. Then, you basically make the inner (double) layer first, but don't drill at this time. You glue the outher (single) layers left and right to the inner one, drill and through plate, then expose and etch the outer ones. For a six layer you expose/etch the inner ones but dont drill (just one work step more) then apply layer 5 &6 as described before with a four layer one. There is no difference actually to a four layer apart from this.
It requires to use laminate for expose and etching so as the holes are coverd during etching but that's a requirement with through plating anyways. I never had a single "faulty" board so far. Once you are a bit used to it it's really no rocket sience.
The trick is to have some (simple) tools to have the stack propperly aligned. I do this by first drillng two holes diagonally oposite to each other and use those to position the films for exposure and of course also to glue propperly aligned. As glue I use regular two component (5 minute) epoxy and a special device primarly consisting of two vises to apply the needed pressure. I have some pictures of this somewhere - well, it's really getting time that I update the webpage showing these things too but sparetime is rare at the moment.
The resuliting boards are absolutely ok for prototying and private use
- really a good way. Once you have the equipement and experience it's also very cheap. I.e. a four layer 3x3 inch sized board with say 200 holes costs about $10. If you also apply a solder stop mask (which is also available as a laminate) you can't optically distinguish the boards from boards made in a board house. Again, this is a good solution for prototying and experimenting but I never would come to the idea to make a production run this way. That's definately what board houses are here for.
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