I have been working to make an equivalent of the standalone arduino found here. This time not with an Atmega8 (or Atmega168) dip, but with an Atmega168-MLF32.
This is in addition to the 28dip to ML32 converter board I am working on here (mentioned here).
Before creating the PCB design, I would like to have someone verified if everything is correct. Please note that the MLF32 has more pins that the dip versions.
I used 2 pinheaders for the analog ports and 3 for the digital ports. Maybe it is preferred to use 1 pinheader for the analog ports and 1 for the digital ports?
Edit: and when I want to 'Change to board', I get an error message saying: Unknown object type
Re: the capacitors, usually you put one as close as possible to the regulator output, and one as close as possible to the Atmega power supply pins. If there's onlly an inch between the reg and the Atmega, you can just use one cap.
The .1 power supply cap is used because regulators can sometimes go into self-oscillation, and this prevents it; the Atmega side cap is to kill off any spurious high-frequency junk in the power supply line before it gets inside the chip. Reference designs for regulators usually have a .1Uf cross the input and ground as well.
D
PS If you can get that far drawing a schematic you are definitely not a n00b, what you have is very good.
Daniel,
This design is derived from the Standalone arduino (here: http://www.arduino.cc/en/uploads/Main/atmega8_schematic.jpg). So it wasn't that hard after all. Thanks for your compliment, but I still feel a little like a noob. Maybe a rookie describes it better?
You put C3 and C4 in series with the supply voltage. They should be connected between VCC and ground, otherwise there will be no supply voltage to the chip.
you need a couple of 100uF capacitors , before and after the power regulator because when the first thing you connect to the board starts using power the voltage will drop and reset the processor...
have a look at the arduino schematic for a reference
Thanks Massimo, I will make this change. For the rest everything is ok? Previously I was told that I made a mistake with C3 and C4.
Btw, this schematic is derived from the image below, all capacitors that are suggested to add, are not in that schematic! Maybe the schematic in the image below should be updated with these capacitors?
I am currently not ordering this design. I am awaiting a couple of DIP to MLF32 converter boards I designed (should arrive within 2-3 days) and if they turn out to work, I will submit an order for this. If someone is interested in this, please let me know here, so I can reconsider and submit my order earlier.
Lots of folks are using really small (0603 and even 0402) components, but I prefer 1206 for the stuff I do by hand. IIRC, the SMT parts on the NG are 1206.
In case you didn't know, those package sizes are X and Y dimensions in hundredths of an inch - an 0402 package is 0.04" x 0.02".
These are fixed 5V regulators, but only 100mA output, plus they have an enable pin. They take different capacitor values than the 78x05.
They'll work, but they are not drop-in replacements for the 78x05 on the Arduino. Read the data sheet and design your circuit accordingly.
Their benefits are they are low dropout (LDO), so you can run them from a 6V battery and still get 5V, and they're also tiny - not a lot larger than the SMT resistors on the Arduino NG.
Untill my previous post, I didn't know anything about SMD/SMT, just that those were the tiny parts on various electronic products/projects I have seen.
I tracked down most of the items I am using in the Sparkfun Eagle library, but it seems that they don't sell everything I would need for this schematic.
These are fixed 5V regulators, but only 100mA output, plus they have an enable pin. They take different capacitor values than the 78x05.
Is 100mA enough? I am not sure about this.
Digikey is one of the suppliers I could buy on a regular basis, but I would need to have a credit card for that and I don't have one. They don't accept PayPal payments
