atmega 2560 design

hi i have long used arduinoethernet for some projects.
and it works 100%.
Now I want to design my own kit, because then I can get it to fit in the box I feel like.

I'm a little unsure about what I should do. why.?

well because there is everywhere a something is aduino compatible? is it just pin connections ther are the same?
I know it may be a mouthful, but I was going to take the big step and make a atmega 2560 kit.

I would design it so I can use the "USB2SERIAL" that comes with the ethernet kit.

The question then.
Bootloader? it is something to be programmed to the processor, before I can use the kit with Arduino program.

Is there a TUT for this topic.

ok i have found out that the Arduino program can burn a bootloader.

So far as I understand so I build a standard solution with crystal etc and use the usb2serial as I have to program the bootloader? problem solved.? is it so easy.

kimjessen:
So far as I understand so I build a standard solution with crystal etc and use the usb2serial as I have to program the bootloader? problem solved.? is it so easy.

Yes.

The Arduino isn't much more than an ATmega processor (328P, 2560), 5V power, a 16 MHz crystal or resonator, a bootloader, and a USB-to-Serial converter. Pretty much that is all you need to run Arduino sketches.

You can get fancy and add things like the LED indicator, the Reset button, Form-factor compatibility (so you can use Shields), etc.

super, that was easy. I assume I need to use
TXD0 and RXD0 to program the kit, just like the Arduino etherneth card.

Need SCK.MISO.MOSI.Reset.+5.Gnd for ICSP to program a bootloader before Tx/Rx/Reset (from DTR thru 0.1uF cap) will work.
Or use ICSP for programming and skip serial downloading.

ok thanks so I can get .......
I need what?.

I have this one. it seems to be prepared for ICSP.?

I will just pull the legs out from the processor as you mention and then it should be in place.?

http://www.bc-robotics.com/shop/usb-2-serial-converter/

There are many available, FT232RL based, CP2102 based.
I can't open that link from here, make sure to choose one that has the 3 signals plus power, gnd.
This one is nice to add to a card.

No soldering those little pins, just add 0.1" headers. Low cost too.

here is a picture of the USB2SERIAL I have. I think that it can solve it.?

I have made a minimum SCH.

I would say that it should work both with Serial comm. and programming of the Boot loader.
what do you say.

I've got 5 ATmega2560 from a Danish supplier as sample, so before I make it big I just wanted to make a minimum system to see if I can get it to work.

Atmega2560 basic.pdf (41.2 KB)

You need a 100 nF capacitor in the line from CONN_6 to the Reset pin. That allows a sudden drop in the DTR line to reset the Arduino without holding it in reset forever. See C7 on the official board.

hi super it is done??.

Otherwise it should work?

Need 100nF power supply decoupling caps on the Vcc/AVcc lines for reliable operation. 1 per pin, located close to the pin.
Are you bringing all the signals to a header pin or something for access?
Could be 0.1" headers, could be something smaller, like JST 1.5mm pitch headers.

Hey it's only basis to see if I can get the life in the processor.

If successful then I have 4 other processor that I will build something seriously.

Right now I aim only by a serial communikation so I can see that there is something that works.

Your proposal for decoupling is made.

I will not use the A / D fungtionen so I assume that it is not necessary to supply AVCC as I assume it is only a referenc voltage?

kimjessen:
Hey it's only basis to see if I can get the life in the processor.

If successful then I have 4 other processor that I will build something seriously.

Right now I aim only by a serial communikation so I can see that there is something that works.

Your proposal for decoupling is made.

I will not use the A / D fungtionen so I assume that it is not necessary to supply AVCC as I assume it is only a referenc voltage?

No it's also used to power stuff for the port that can handle analog inputs and the AVR datasheet says to supply Vcc to the Avcc pin even if not using ADC functions.

Lefty

oh that I had overlooked. Thank you.

Hello.
So now it works. 8) :stuck_out_tongue_closed_eyes: :stuck_out_tongue_closed_eyes:
it took some time and several attempts with PCB laying.

But now it's there.
it is only a basic building blocks that you can build from, the fact is that it works and it is 100% Arduino compatible.

Very IMPORTANT is the 10 Kohm resistor at reset. it shall not be less because otherwise the serial programming device does not reset the controller.

things I used to burn the bootloader:
http://www.jyetech.com/Products/073/e073.php
stk500boot_v2_mega2560.hex ( bootloader )
http://www.khazama.com/project/programmer/

I know it's very basic but it's something like that I have long been looking for.

it's something you can build on and dominate in its own way.

hope that there is someone who can use it.

I have attached the boot loader file that works for me so I would assume that it also should work for others too.

atmega2560_basic.pdf (71.1 KB)

stk500boot_v2_mega2560.hex (20.5 KB)

færdig kit_1.jpg

100 pin processor and you only bring out 8 pins?
What is it doing?

hello.
basic - nothing.

I just hate to draw PCB without knowing that it works when I'm done.

this is the first time that I create a kit with a 100 pin controler, and I was not sure if I in any way would have success in mount it.

Now I know that I can get it to work, I have 4 ATmega2560 more to complete my project. (I've got them for free as a sample) so I have no problem with that I have used one for testing.

next step is to get a ENC28J60 ethernet thing to run. I think it also gets a little interesting, I have no idea how, but I think I vill succeeded.

why ENC28J60- yes it looks somewhat easier. + I can get it in dil package. and so it is cheaper than W5100.

Any suggestions on how I should do?

Follow the datasheet suggestions.
Post your proposed schematic for review.

thank you I will do.
it'll probably be just a few days but then it comes.
Thank you for your help.