Home Made AVR Devboard

avr_project_distance_measure
In this article, I will show you how to make your own AVR development board for ATmega8 microcontroller.

What is a development board?

In order to learn any MCU like AVR we need a AVR MCU that has all the basic connections like power supply, crystal oscillator, proper reset signal and an ISP connector for uploading a program. All these things are required for any project you will make. A development board is a circuit board that contains all these connections and it has connectors for IO pins of MCU so that they can be connected to any external circuit with ease. So as you see its is like a basic framework. Once you make a good development board and test it, you will have a solid foundation and for your project you can concentrate on the specific requirement of that project. This will also reduce the chance of making errors. Some more complicated development boards have a RS232 level converters(for serial communication) ,motor control chips etc.

Now let’s do it!

I have described the basic connections required by any AVR MCU in Part III of my AVR tutorial series so I am jumping right to the schematic.

atmega8 basic schematic circuit

Fig – Development board schematic.

Things you need are

S.No Components Name Value
01
ATmega8 IC1  
02
Voltage Regulator IC7805 IC2  
03
Resistance R1
330ohm
04
Resistance R2
1k
05
Capacitor(Electrolytic/Polar) C1
100uF
06
Capacitor(Electrolytic/Polar) C2
100uF
07
Capacitor(Electrolytic/Polar) C6
1uF
08
Capacitor(Ceramic disk type) C3
0.1uF
09
Capacitor(Ceramic disk type) C4
22pF
10
Capacitor(Ceramic disk type) C5
22pF
11
Capacitor(Ceramic disk type) C6
0.1uF
12
Inductor L1
10uH
13
Diode D1
1N4007
14
Crystal Oscillator Q1
16Mhz
15
LED LED1  
16
Tactile push to on switch S1  
17
Connectors,IC Socket, Power jack, general purpose PCBs, wires etc    

Note: The voltage rating of C1 must be at least twice the input voltage while that of C2 & C6 can be 12 Volts or more

Components

Fig – Components for power supply

Components

Fig – ATmega8, Resistors, Capacitors and Connectors.

Components

Fig – Veroboard / General purpose PCB – Top View

Components

Fig – Veroboard / General purpose PCB – Bottom View

Components

Fig – Connectors for easy connection/disconnection from MCU pins

 

Now connect the components according to the schematic on a general purpose PCB. You will get something like this.

atmega8 board simple atmega8 board atmega8 board

Fig – Final Board with all components assembled.

Before inserting the MCU, first test the board for any connection error. Make sure everything is according to the schematic. Then check for any soldering errors like loose joints or unwanted shorting by solder. Finally connect power supply of 8 to 18 volts to the circuit by using an adaptor, battery, or transformer (after converting to DC). Check the power pins of MCU in the IC socket with a multi-meter for voltage. It should be very close to 5V. If everything is ok your board is ready.

Note

Some difference in my prototype and the schematic.
  1. The value of C2 is 100uF but I have used 0.1uF ceramic type.
  2. I have not used the reverse protection diode D1. But you should for safety.
  3. I have used 220uF capacitor as C1. Anything over 100uF will do. Also the voltage rating must be double the input supply voltage
  4. I have not used the reset switch. However, it is very convenient if we have one.
  5. I have not used C6(1uF) as it is required for reset switch
  6. I have not used L1 for connecting the AVcc to Vcc, instead I have directly connected them. But if you are planning to use the ADC you should use the L1 as it makes the ADC much accurate by suppressing noise
  7. I have connected a 0.1uF capacitor from Vref to GND as it is suggested by datasheet. Only necessary if you are using ADC.

The same board made with a professional PCB.

A simple ATmega8 Devboard

Fig – A simple ATmega8 Devboard

You can buy it from here at only Rs 450/-. Sorry, but currently I ship it only within India (no International shipping right now).

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Avinash

Avinash Gupta is solely focused on free and high quality tutorial to make learning embedded system fun !

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About Avinash

Avinash Gupta is solely focused on free and high quality tutorial to make learning embedded system fun !

32 thoughts on “Home Made AVR Devboard

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  • By AL - Reply

    Hi,

    This is great! Just like the board sold by sparkfun.com but better :-) I am a very beginner with microcontrollers and circuit designs. Would you kindly explain how you come about to use capacitors and the L1? I know the capacitors would smooth out the voltage to make it more stable, etc. But how did you come about the capacitance values?

    What kinds of tolerances in your resistors and capacitors, e.g., 1%, etc.?

    Thanks. And GREAT WORK!

  • By Avinash - Reply

    Hi AL,
    The ceramic capacitors (0.1uF) are Decoupling capacitor capacitor. They are used to decouple the power supply from the MCU. The advantage is they bypass the spikes frm the power supply. They are placed close to the MCU. The standard value used for this purpose is 0.1uF ceramic disk type.

    The C1 (100uF) is used as a filter capacitor. Its purpose is to further smooth the In put DC input which you may supply from a transformer. Its value is not so important just select is according to the current requirement of the circuit. It the circuit is a consuming one you can increase it (470uF or even 1000uF).

    The two capacitors 22pF connected to the Crystal. Their value is suggested in the ATmega8 Datasheet (see page 27)

    The L1 (inductor) C7 is used as suggested in the dataseet page 202 “ADC Noice Cancelling Techniques”.

    So Now you know how the value are calculated you can go ahead and start building !!!

    For any help we are here :D

    The C6

  • By AL - Reply

    Hi,

    Thanks for the answers. That helps a lot. I happen to find ModernDevice’s tiny Atmel dev board. It’s very interesting. See http://www.moderndevice.com/RBBB_revB.shtml.

    In your answer, you referred to page 202 for the “ADC Noise Cancellation Techniques.” All the Atmel datasheets I looked have 22 or pages not to 200+ pages. :-( They do refer to those pages as well. I kept searching and searching on the atmel.com site but can’t find the complete (200+ pages) of the atmel datasheet. Do you know the link by any chance?

    Thanks.

  • By AL - Reply
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  • By Seemanta - Reply

    Nice pictures man! I really liked you site. I too am a hobby embedded developer!

  • By Raul - Reply

    Hello,
    I have to do a project using ATmega16 and i make your Home Made AVR Devboard and the programmer for serial. I use PonyProg .
    And…i have some problems:
    I connect the programmer and Devboard to the PC serial, and when i tray to read the fuse bits, i receive the next error: “device missing or unknown device -24″, i clink the Ignore button and finally read the fuse bits, but all are selected.
    When i tray to write o small program into controller (i tray to on/off a LED)i receive the same error; i hit the Ignore button, PonyProg write something, verify something, but finally he says : “Write fail!!”.
    So … what is the problem? I skip something??
    One more question: when i write something into controller , the Devboard must to be power ?(i tray the both )

  • By Avinash - Reply

    Hello Raul,

    :)

    Please check connections. Communication with Programmer < -> Micro is not ok.

    Yes devboard should be powered while programming.

    Keep all cables as short as possible. Check DB9 PIN connections. Select Correct COM Port.

    If all else fails buy a ready made USB Port based programmer from here

    http://shop.extremeelectronics.co.in/product_info.php?cPath=21&products_id=28

  • By Suhas - Reply

    Hey, Is it possible for you to provide the PCB design of the Devboard?
    I am interested in making one myself.

  • By Zvonimir Cicak - Reply

    I’m interested also if you can give pcb layout of your Devboard so we can make it at home…

  • By Rohit - Reply

    you are doing good work, looking forward to your tutorial on rf transceiver.

  • By Mitesh - Reply

    Hi Avinash,
    Nice kits! I am in the US (used to live in Hyderabad) and can purchase these from you and sell them here in the US. I have friends/family that routinely fly back and forth. Which city are you located in? If it is Hyderabad/Bangalore/Chennai, I can have somebody purchase some of them and get them to me over here.
    Thanks.
    Mitesh
    aminmitesh@hotmail.com

    • By Avinash - Reply

      @Mitesh

      Thanks! We are in Jamshedpur. I can also send these to you by DHL Express. We export many Items by DHL Express. Please tell me your background. Do you have experience in E business or Bussiness Related to electronics? Then you may represent us in USA. After India our Most of our Visitors are from USA and its a Great Market.

      PLEASE REPLY TO MY EMAIL avinash [ at ] eXtremeElectronics.co.in

  • By Ramesh - Reply

    Hi Avinash
    really gr8 job

  • By Rohit Sharma - Reply

    You know Avinash , you are a good guy.

    I really like the tutorials, (party because i had summer training on Atmega microcontrollers) these tutorials really helps and i am looking forward for more (specially on wireless module [read Zigbee])

    :)

  • By pp - Reply

    i want to make the development board for atmega16 …….is there some ckt diagram for this

  • By Stravy - Reply

    You are really really helping the future generation of engineers. I used to work on user interface (front ends) using all sorts of protocols which made me interested in embedded systems. I find AVRs particularly useful and interesting. Your tutorials and projects have made learning rather easy and stimulated my thought process.

    • By Avinash - Reply

      @Stravy

      Thanks ! ;)

  • By mKs - Reply

    can we use the same ckt diagram for atmega 16 connecting appropriately the pin nos?

  • By Itus - Reply

    Thank you a good deal! I truly enjoyed reading this.Looking via these posts and the info you?ve provided I can appreciate that I nonetheless have a great deal of things to discover. I will keep reading and maintain re-visiting.

  • By Arup - Reply

    Can you share the pcb layout of the professional version? I’d love to make that neat one in my home.

  • By mujtaba ali - Reply

    hey,
    plz provide the pcb layuot of this poject…..

    Thanks in Advance

    • By Arup - Reply

      Mujtaba, I’ll publish one more functional dev board design soon.

  • By sudeep - Reply

    gud work and easy to understand……
    i have borrowed your idea to create my own dev board with more peripherals attached to in. pls check
    http://goavr.blogspot.com/

  • By Bechir - Reply

    Hi
    I have a question about the used atmega8 in the circuit. Is there any code flashed in it or it is used directly from the store without any hex code inserted in it

    Thank you for responding

  • By Roshan - Reply

    hi
    am a beginner to this.
    i am doing a protect for my uni.i was planing to use arduno mega 2560(coz i need 16 analog inputs). but now they saying that i ve to use costume made(by my self) and not to use developer board.
    can any one help me with this.coz i ve planed my coding
    and every thing for mega.
    thank you

  • By prabhu - Reply

    Hi

    i need ATMEGA16 development kit, where i can get it in bangalore and how is the price.

    Can u tell me any bodys knows

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