In circuit AVR programmer (ISP).
Perhaps this circuit is the simplest AVR programmer you can build.
Its great advantage is the ability to program almost any AVR
microcontroller, without the need to remove it from the circuit
in which is connected (in circuit programming).
Actually the circuit is a simplified version of the
older SIProg programmer. For more details read the article
A simple SI-Prog.
Almost any AVR based circuit presented in this website is
compatible with this programmer.
- Two Zener diodes at 5.1V (low Watt).
- One 10KÙ resistor (1/4 Watt).
- Two 4.7KÙ resistors (1/4 Watt).
- One 15KÙ resistor (1/4 Watt).
- One BC547 npn bipolar transistor.
- A female 9 pin DSUB connector (for PCB).
- A female pin header (5 pins. If you have one with more pins, just
- A small piece of a Veroboard.
- Wire for connections.
- Solder and soldering iron.
You don't need any external power supply.
Here is the schematic diagram of the In circuit AVR
Attention: In order this programmer to work, the
circuit in which the microcontroller is connected, must have a
10KÙ (or 4.7KÙ)
pull-up resistor on AVR's reset pin.
Generally we call pull-up
resistor any resistor connected between the power supply and one
of the I/O pins of the microcontroller. On the other hand pull-down resistor
is a resistor
connected between the I/O pin and the ground (GND).
In order to
succesfully program the microcotrollers, you will also need the appropriate
software. You can find a lot of free software compatible with
this circuit. However in this article, I will show you the
settings only for icprog (www.ic-prog.com)
and PonyProg (www.lancos.com/prog.html).
ic-prog you can see the necessary settings in the following
If your computer
isn't fast enough, increase the I/O Delay. With a Pentium II 333MHz, I
didn't have any problems with the delay.
Attention: In order to
use the Direct I/O interface setting in Windows XP, you need to
download the appropriate driver from the icprog's website
For PonyProg the settings are just like the next picture
following pictures you see the programmer build on a small piece
of a Veroboard (StripBoard).