Thanks, again !
On first "boot" (when I power up for the first time the montage) I read the over-load current ( about 300 mV) and I store the value into eeprom. Next time, I read the current and if this is > value memorised, then I stop the motor. This works fine , but, time to time, the PIC is dammaged. I use for power LM 2931AZ5, with 100uF and 100nF .I really don't understand why this...so I think maybe it's something wrong with this pin (6). Thank You for support !