AVR Parallel Programming_2

One of the simplest AVR programmers is a LPT port programmer. This is due to the fact that the signal levels of the LPT port are compatible with the signal levels required for programming the ATS. Therefore, signals from the LPT port can be directly applied to the microcontroller (resistors are needed to protect the port from accidental closures only). Such a programmer can be assembled from scrap materials in just 5 minutes!
As you can see, the LPT programmer circuit for the AVR is extremely simple:

For this LPT programmer, we need :

Resistors can be used any that you find in the range from 100 to 150 Ohms. You can assemble a programmer without resistors at all, but then it will become even easier to burn the port. As a loop, you can zayuzat IDE loop. When connecting the loop, for a more stable operation of the programmer, each “signal” wire must alternate with the “earth” wire. This will reduce the level of interference induced in the lines and thereby increase the length of the programming wire. The length of the loop should be within 50 cm. Still need a connector for connecting to a programmable device.

Building LPT programmer can be made in 5 steps:

Jumpers between connector legs 2-12 and 3-11 are needed so that our programmer can be seen for programs as the STK200 / 300 programmer (STK200 / 300 is a kind of standard and therefore our programmer will become visible for many programs).
In order for our LPT programmer to work, we need a program for programming through the LPT port , the device board to which we will connect the programmer and the test firmware for the microcontroller.

General recommendations:

– The LPT port is quite gentle – it is very easy to “shoot”, so be careful when working with the port.
– I would recommend doing a separate connection for the “earth” in all programmers. This is necessary so that the “earth” can be connected first and equalized the potentials of the “earth” of the programmable device and the computer. (For those who don’t know, if you have a computer plugged into an ordinary power outlet without a grounding contact, then because of the features of the computer’s power supply filter, there is always 110V potential on the computer case. With a “successful” connection to the programmer, this is enough to burn microcontroller or LPT port of the computer.