Hi everyone !
It was a while when I last wrote to this forum. This does not mean that I would have ignored it - I have not just written here.
I finally got fed up with my STK200 dongle and especially the very short cable with it. I have my "desktop" computer under my table and would like to have the project on top of it (the table not the computer). With the 10 pin cable this is not possible so I have had a small side table (beer box) to get a good aim onto the project in hands.
So I have been spending some time in reading this forum and especially on posts dealing with dongles. The net result was a Parallel Port Programmer Dongle.
(Click on the image to reach the project site)
The dongle is 3-5 volt compatibel and it is fully compliant with the old STK200 dongle with the exception of a missing /LED signal. I have never had any use for it and since the HC125 only offers 4 buffers I simply left it out.
The 10 pin pin header had to go. It is all too easy to connect it the wrong way around and the cable is not designed for repeated push-in/pull-out operations. And it is short.
So I made use for the SMD RJ45 connectors I have sitting in my shelf. Yeah, I have some thousands of these.
I am sure there is a recommendation for pinning this connector for programming purposes. However, I decided to make the pinning such that the MOSI, MISO, SCK nad /RESET signals can be connected on the project without making any criss-cross jumper design. Just four parallel lines coming out of the MCU and going in into the connector. Same applies to the VCC and GND lines - well - at least with Mega32 of which I have a good supply of.
Another reason for choosing the RJ45 connector is the supply of suitable cables. It is endless. These are much more available than the 10 pin flat cables.