Coreduino

Coreduino is another clon of amazing Arduino board. Main advantage of Coreduino is compact size, minimized price and easy connection to a breadboard. If somebody don't know what Arduino is please visit website www.arduino.cc for more information, because Coreduino is based on the Arduino concept. In this post you can find information about Coreduino module, USB and Serial programmers for Coreduino.

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Coreduino:
When I first met the Arduino I was really impressed by this great idea. Arduino is very powerful and extremely easy to use. Big Arduino community share projects, components, libraries and codes, which save time to all people who wants to do similar projects. Programing of the Arduino is very simple. Thanks to bootloader, which is programmed inside the ATmega by clicking on one icon in Arduino IDE, the code is loaded and executed in the microcontroller.

I wanted to have my own Arduino but I also wanted something more universal. I took only core components from Arduino and put them to as small PCB as I was able to manufacture practically at home and Coreduino came to light. It consists only from few components: microcontroller ATmega168, crystal 16MHz, reset button, some resistors and capacitors and header for ISP, USB or Serial programmer and also headers for connecting to breadboard.

I put the programmer to stand alone PCB because you can built only one and use it for as many Coreduino boards as you want. This save your money against Arduino board, where each board has his own programmer.

Coreduino is compatible with Arduino Decimalia. It also supports RESET from RTS or DTR line.

Coreduino has three solder bridges (W1, W2, W3), which allow you to make following settings:
W1: allows to supply Coreduino from ISP programmer
W2: connects Vcc to Aref pin
W3: allows to supply Coreduino from USB programmer (see bellow)

Schematic of the Coreduino

Assembly diagram (top side)

Assembly diagram (bottom side)


3D model made in Google SketchUp

Assembled Coreduino (top side)


Assembled Coreduino (bottom side)


Description of pins

USB Programmer:
USB Programmer is actually USB-to-Serial interface. It consists from USB-to-Serial converter chip FT232RL. It is more or less connected as in datasheet schematic. RTS line is also connected to the programming header to allow reset function of Coreduino.

USB Programmer has three solder bridges (W1, W2, W3), which allow you to make following settings:
W1: logic levels will be set to +5V
W2: logic levels will be set to +3.3V
W3: connects supply voltage to programming header. It allows supply Coreduino from this programmer. Supply voltage depends on logic levels voltage set by W1 or W2.

Schematic of the USB programmer


Assembly diagram (top side)


Assembly diagram (bottom side)


Assembled USB Programmer (top side)



Assembled USB Programmer (bottom side)

Serial Programmer:
The serial programmer is easier and cheaper solution for programming of Coreduino. It consists of two level shifters. LEDs on the board indicate sending or receiving data. Serial programmer is not able to supply power for Coreduino.

USB Programmer has two solder bridges (W1, W2), which allow you to make following settings:
W1: use RTS line to reset Coreduino
W2: use DTR line to reset Coreduino

Schematic of the serial programmer


Assembly diagram (top side)


Assembly diagram (bottom side)


Assembled Serial Programmer (top side)


Assembled Serial Programmer (bottom side)

Bridge:
Serial or USB programmer can be connected to the Coreduino with help of small bridge.

Assembly diagram (top side)

Assembled bridge (top view)


Coreduino <-> Bridge <-> USB Programmer

LINKS:
Download schematic, assembly diagram and PCB.

Note:

I think that somebody of you could be interested in Coreduino and because the board is on the edge of home manufacturing, I'm willing to arrange ordering of PCBs in professional PCB manufacturing company (PCB would be with vias, solder mask and silk screen). The more people will append the better price will be. In case of interest please write an email to diy4fun@gmail.com.