I have decided to try to find some simple and very cheap programmer to try with it. My experience with the PIC chips told me that may be the best solution would be to find a circuit of serial programmer, working on the RS232 computer port. ATTENTION: This will work only on PC having real RS232 serial port. USB to RS232 adapters could not work. If the port has TTL levels - it would not work also. Searching in the Internet I found the following circuit. (Copyrights : Olimex). It is very simple and I hoped that it will be reliable.
- 1 x RS232 9-pin female connector - my had plastic housing
- 1 x 6 or 10 pin ISP connector (depends on the type of your ISP cable)
- 2 x zenner diodes 5.1V
- 1 x diode 1N4148 or similar
- 1 x NPN BJT 2N2222, BC864B...or similar
- 2 x 10 KOhm resistors
- 2 x 4.7KOhm resistors
- 1 x 33 Kohm resistor
- flat cable (6 wires)
It had the metal pattern shown on the picture.
Step 4: Finished!
Step 5: Time to Test...
I have used the "Ponyprog" software. It can be downloaded here.
I decided to try the programmer on some more simple AVR chip, instead on ATmega2560, because if a problem appears it will difficult to find what the source is - or the microcontroller, or the programmer. For the test I have used ATmega32.
How to connect the ATmega32 to program it the the ISP can be seen on the picture.
To program it I have used a breadbord with supply board.
In opposite to the USB AVR programmers, which can provide the power supply for the programmed chip, this programmer requires that the chip is supplied by an external power supply. Even more... this supply also must be connected to the "VTG" pin of the programmer.
Step 6: The Programming...
The programmer is inserted in the RS232 port.
"Ponyprog" is started.
First the connection ports and the type of the programmer must be defined.
Step 7: Calibration ...
Step 8: Let's Try to Communicate...
We can read also the fuses.
Now we have for less than $2 a working AVR ISP programmer which fits easy in our pockets.