A credit card sized Ethernet Arduino compatable controller board

Step 6 Parts LIst

Here is the parts list:

Semiconductors:

Micro - ATMega168 or ATMega328 - DIP (the 328 provides extra code space)
Ethernet - Microchip ENC 28J60 - DIP
74HC08 - Surface Mount
3mm LED X2
5mm LED
1N4004 Diode
78L05 Regulator
78L33 Regulator
16 Mhz Crystal
25 Mhz Crystal

Resistors

50R x 4
270R x 5
2k7 x 2
10K x 3

Caps:

18pF x4 - Surface Mount
100nF x 4 - Surface Mount
10uF x 3 - Surface Mount

Hardware:

28 pin socket  x 2
4 pin dip switch
RJ45 MAGJACK - Has to be a MagJack, as that has the ethernet isolation transformer inside it http://www.sparkfun.com/commerce/product_info.php?products_id=8534
10 pin header
6 pin header
5 pin header
2 pin header
Small Pushbutton switch

Arduino Ethernet PCB

Comments

[kbates666]

According to Microchip the operating current of the ENC28J60 is 250mA. You list as using a 78L33 when it can only provide 100mA. Why is that?

[drj113]

Wow - I didn't see that - I made an assumption that it was a small chip and it wouldn't be a problem. The board that i have made has been working for ages with no problems.

Doug

[thiagottjv]

Hi, i'm from Brazil... i can't order the ENC 28J60 from Micriship and shipping from Farnell or other big dealers are always something like R$40... Someone know any other store that i can buy them?

[thiagottjv]

Oh, i found that here:
http://www.coolcomponents.co.uk/catalog/product_info.php?products_id=55
Good price... good shipping...

[tech industries]

Could one perhaps eliminate the 74HC08 and just use a 3v3 regulator instead? I happen to have one, but not the '08...

[drj113]

While it is possible to run the AtMega at 3v3, there are a few problems that you may run into;

1. Programming it would be tricky, as the FTDI cable based programmer runs at 5V.
2. My reading of the data sheet is that the maximum clock speed for the AtMega328 at 3.3v is 12Mhz. You would have to load a new boot loader that would understand the new speed.
3. The standard Brown out detect voltage is (I believe) 4v. Again, changing the boot loader is needed.

None of these things are show stoppers - they have all been done for supporting the newer Arduino boards, you just have to be careful.

[tech industries]

Thank you for your reply-
Actually, what I meant to ask was, I saw above in the schematic that there is a separate "power" circuit (one that supplies both 5v and 3.3v) but no mention of the 74HC08 (forgive me if I'm misreading it). Could I construct two separate circuits, as shown above? Or is the "power" circuit actually an explosion of the '08's function? Thanks!

[drj113]

Ahhh - Thats ok.

The HC08 is represented as the two 'AND' gate sumbols (elongated D shapes). UNlike microprocessors, they are what is called 'discrete logic'. Each HC08 chip contains 4 separate AND gates in the package.

The HC08 gets its power from the +5v regulator.

[xillwillx]

whats a good site to buy most of these components? Ive been searching and only find a few parts at each site

[darthneo]

There are a few popular ones, the ones i use the most are http://www.digikey.com/ and http://www.mouser.com/ there are also other sites, i think jameco.com sells parts, and sparkfun carries a limited selection (sparkfun is overpriced imo)

There are also some sites that sell weird electronic stuff such as Electronic Goldmine http://www.goldmine-elec.com/

[Reki3]

Do you, by chance, have links for the places where we can get these? I have checked the more known sites and have not found a few things.

[drj113]

I got the ENC28J60 from Microchip direct. They are only a couple of bucks each - and Microchip provides samples.

[Puze]

So could this http://uk.mouser.com/ProductDetail/Microchip-Technology/ENC28J60-I-SS/?qs=sGAEpiMZZMsloqAEgcTS55szDcrVZq9x be used possibly with a change to the circuit board.  Thanks

[drj113]

Yep - that chip would work fine - You would need to modify the board for the diferent part layout

[MstrChief]

Hi,

I am looking to minimize the arduino pins required to drive the Ethernet controller.
What is the purpose of using the interrupt (INT pin on ENC)? would it be possible to omit it?

Thanks.

[crazymacleod]

Hey Just to throw In an idea for power, I've been hitting my local goodwill and other thrift store's and picking up cell phone charger's to use a my power supply. They provide more then enough current and I haven't had any fail yet. I get the eletronic kind not the big bulky thransformers. as I believe they are better regulated. They've been renging from $0.50 to $0.99 Not bad?!

And you can attach your project to it and just plug it in.

[wcbzero]

Any chance you have a part number for the mag jack? I picked some up and found they had a different pinout.

[drj113]

It is this one: http://www.sparkfun.com/commerce/product_info.php?products_id=8534

I have amended the parts list to include that link. I don't see why any other MagJack couldnt be used, although the board may need to be changed.

[wcbzero]

Mine wont work because the pins are strait across in a single row, but thanks!

[pocketscience]

Hi, How are you getting away with those small TO-92 regulators? I thought they could only provide around 100-150mA? Max requirement on the ENC is 180mA, and once you start adding external components you'll need more than 150mA for the ATMega as well right? Cheers,

[drj113]

I agree that it is tight, but my measurement of current consumption is about 135mA for the lot. The kinds of sensing components that I add only add a couple of mA to the load.

I would *love* to identify a better switching reg, but locating one that is (a) cheap, and (b) easily available is a bit tricky.

[mfmjos]

This may be a super newbie question. But are you sure you meant 2k7 resistor? Should it be 27k or 2.7k perhaps?

[drj113]

2K7 means 2.7k The way or writing it means that even when the document is photocopied, the decimal point never goes away. 2.7k, after a couple of copies, can easilly turn into 27k, as the decimal fades......

[mattadamsnet]

I was up at 2 am putting together the parts list to order, Mistake number 1, never take the credit card out past midnight. Any who For the life of me, in my delirium, i couldn't find "Micro - ATMega368 - DIP" Anywhere. Only to wakeup this morning and realize it should be 328 or 168 -- Matt

[drj113]

Arrggh! I know the feeling - and yep, I stuffed up as well - where did you see the reference to ATMegs368? I will fix that, I normally use the 328 chips, as they have extra program spage, and only cost an extra dollar!

[mattadamsnet]

Step 6: Parts List

[drj113]

Done! - thanks for that

[diamantmatch]

(removed by author or community request)

[diamantmatch]

i can not seem to find the beads resistance?? what bead do i need? thank you :D

[drj113]

Any ferite bead will work fine - I use FX4 beads.

[diamantmatch]

(removed by author or community request)

[diamantmatch]

i am just replicating your circuit and drawing my own but still can not find the type of bead. just as im buisy with the dip switches i see that you have them connected straigt to a header and to the switches witch either are ground or float since i see no pull up resistor? wouldnt it be verry usefull to put a pulup between them ? to prevent unwanted ip's? cheers diamantmatch

[drj113]

The resistors are not needed, as I use the weak pullup function in the AtMega chip

[diamantmatch]

the transistors on the top of the pcb arent on the partslist and i don't relly understand what they do? damn i want an edit function here! * hint hint instructables ppl * greets diamantmatch

[drj113]

The 'transistors' are acrually voltage regulators - 78L05 and 78L33

[jeremyvnc]

To alleviate any confusion, I think you mean ATMega328 for the micro. Nice instructable though!

[diamantmatch]

no he means ATMega168 since the code is not any bigger than 16kbytes.

i would really love to build one of these but i can not seem to find anywhere to buy these parts ( the ENC28j60 ethernet controller and the 74HC08 gates.. i would preffer to use the 74HC08 as a dip package but smd would be fine, though a lot of work..).

why is the ferrite bead nessecery?? i never saw the use of beads..

you used 18 pf caps for the crystals hough a lot of people bealive that 22pf would work better..? why do you use 18 pf?

verry nicly done thanks for the insparation

[drj113]

I normally use the Atmega 328, as I appreciate the extra code space. The code will fit into a 168 though. the Ethernet controller you can get from Microchip Direct, and I just get the 74HC08 from a supplier on eBay. They are very cheap. I have always used 18pF caps (I thought the Arduino reference design used them) - either will work ok. And finally the ferrite - it is a low value inductor when a wire is passed through it - it is not completely necessary, but it does help to reduce the noise on the 3v3 supply.

[diamantmatch]

the Ethernet - Microchip ENC 28J60 - DIP on microchip is in a SPDIP package i cant find the DIP type can you send me a link? ( elseway ill just buy the SPDIP type but it looks cleaner :P (i just boght 3 AND gates in a DIP package on ebay :) hope they work and my pcb design works too :P) thanks diamantmatch

[drj113]

Ahh -- The Ethernet controller is a SPDIP package - just like the AtMega. I am not aware of a normal wide DIP version.