Oleg Sergeev
Thanks!

Your explanation is very easy to understand and complete, my problem was:

A big confusion with the different ways to do this (ISP, API), after I red your post I understood very well. This is the story I have a unit is a tank monitor panel that works on RS-485 network it also has a display and membrane switches to control its function, the software is written in assembler because of the amount of different options this panel has, a software on c will need more memory and I also has a limitation on the size of the unit.

So I need it to be able to update the software ones the unit is build because we pot the PCB after it have been tested there is no way to get the uc out, so I need it a serial interface for later reprogramming. After I red your posted I found out I was doing it right with the RESET and PSEN to get the uc into the boot loader, I’m using FLIP, what happened is that I had a bad connection with the serial port that is why it didn’t work before. All this and my big confusion make me think that I was missing something.

Now is working good I use dip switches to isolate the RESET and PSEN of the controller from the rest of the PCB and I build another manual reset on my cable with two push bottoms one for RESET and the other one for PSEN so its just synchronization first press and hold reset the press and hold psen let go reset and then psen and it is working I have FLIP connected and updating my software.

Abut the codes I posted before that was another one of my test so disregard. In the middle of my confusion I was trying to do it with my own boot loader, which I don’t need it is not good for me that the boot loader can be activated by software.

Again Thanks!

Thanks to Erik also, you were right that programmer was a scam.