Hi ,thank u very much 4 ur help , in fact it was the problem with the 15 V source, althought after measuring the voltage in Vpp i saw it was 11V with 15V source, i have to use the Ez4d software, cause neither of the other wants could program or even erase the chip,i still have a problem i can only program the chip, but im not able to read it, what could be the bug here?