Saturday, January 8, 2011

Tutorial 2: Making a development board for ATmega series.

Name: Making a development board for ATmega series.
Application: This is small development board & can be used with ATmega 16/32/64/644 etc.

Requirements and components:
There are 5 baric parts of the development board –
1.       µC holding circuit.
·         General purpose PCB
[If you’re not good with soldering then this can be implemented with two bread board]
·         40 pin IC holder
2.       Power supply circuit.
·         Small sliding switch (with three terminals)
·         Diode 1N4004
·         Electrolytic capacitors -100µF/25V, 10µF/25V
·         IC 7805(or 78L05)
·         Heat sink for 7805(with screw)
3.       Programming pins.
·         This is discussed letter.
4.       Reset circuit.
·         Resistor- 1.2KΩ
·         Electrolytic capacitor- 1uF/10V
·         Micro press button switch(D1/D2 press button switch with two legs)
5.       Crystal circuit.
·         Ceramic capacitors – 22pF
·         Crystal – 16MHz
[Note: Atmel Corporation ships ATmega AVR ICs with internal RC oscillator @ 8MHz. Hence, if you buy a new brand IC from stores then you don’t need to implement crystal assembly. But if you chance the “Fuse bit setting” (just mark the word here!!! we will see this in detail) then you need crystal assembly]
6.       Other
·         Male and female burg strips
·         Wires and soldering accessories.

Connections:
Following diagram shows the connection set up for ATmega16/32
If you see in the diagram all the above parts of circuit are implemented. SV1 and SV2 are the female (or can be male) connectors connected to the port C and port D of IC. One can also connect same connections to the Port A and Port B. But, I recommend that you leave port A as it is. (i.e. don’t connect anything to port A, because this port is used for internal ADC of MegaAVRs.)

One must take care of few things as-
·         Solder the IC base only don’t solder the IC directly to PCB.
·         Watch the position of VCC and GND pins as well as soldered tracks.
·         One can solder the crystal directly but it is good to have female burg at crystal, so that you can change the crystal whenever you need to do so.
Basic connections for development board

One pint to be noted here is that, when you mastered the skills of soldering you can start developing more complex circuit on general purpose PCB. And once u got all things correct on general purpose then you can start develop your own PCB module. But still I recommend the general purpose is better than to have a PCB module as you can modify the circuit on general purpose PCB.
Here are the some of the boards developed by me -



Cost and availability of components:

You can just figure out the components required from above mentioned list and the diagram. Cost of all the components is very less as compared to Atmega ICs.
·         Cost of all components except IC = Rs. 100/- [INR]
·         Cost of IC[ATmega 16/32] = Rs. 250/- [INR]
  
Note: All components will be available @

GALA ELECTRONICS
20, Kalpana Building, 1st Floor, 357,
Lamington Road, Opp. Police Station,
Mumbai-400 007 (INDIA)
Component Division
Tel.: (022) 2386 3549 / 2382 3550
Kit Division
Tel.: (022) 2387 9562
Fax: (022) 2382 3552

Tutorial 1: Parallel port programmer for Atmel MegAVR series.

Application: This programmer can be used with ATmega series. (E.g. ATmega16/32/8/48/88/168.)

Requirements and components:

·         PC with windows xp & parallel port (DB-25 port)
·         Software Ponyrog2000
·         [Note Download any version of PonyProg2000 for Windows 9x/ME/NT/2000/XP distribution]
·         DB-25 male connector and its case
·         FRC cable [Flexible Ribbon Cable] -- with more than 5 strands.
·         Soldering iron & soldering wire.
·         Burg housing connectors (both male & female)

Connections:
DB-25(parallel port) Pin out


Burg housing connectors (male and female)




Connections for Parallel port programmer



Parallel port pins
µC pins
6
8
7
6
9
9
10
7
20-25
11
connectivity table for programmer


Cost and availability of components:
Part name
Quantity required
Cost (for each unit)[in INR]
DB-25 male connector
1
10/-
DB-25 plastic case
1
10/-
FRC cable
1 meter
16/-
Burg housing connectors
(both male and female)
1
(set of 40 pins)
32/-
Total
68/-

Note: All components will be available @

GALA ELECTRONICS
20, Kalpana Building, 1st Floor, 357,
Lamington Road, Opp. Police Station,
Mumbai-400 007 (INDIA)
Component Division
Tel.: (022) 2386 3549 / 2382 3550
Kit Division
Tel.: (022) 2387 9562
Fax: (022) 2382 3552

Note: Above programmer works perfect with ATmega 8/16/32/44/88/168.