It have earlier been reported that both PICkit 4 and also ICD 4
have destroyed older PIC devices with too high Vpp voltage,
when Programming with externally supplied Vpp on the /MCLR line.
See this thread: https://www.microchip.com/forums/FindPost/1114960
With Restriction on voltage range for Vpp, PIC18F26K22 might also be at risk.
Because of this, I have Not before used my PICkit 4 for any 8 bit PIC devices
Using MPLAB X v5.25 for PIC18F26K22,
ICD4 and PICkit 4 both show up as tested and supported for Programming and Debugging.
I have a link to connect PICkit with Target board, made for some other purpose earlier,
with a 180 Ohm series resistor in the _MCLR line, originally intended to monitor current in the line.
So encourageded by this thread, I have used it to make some measurements.
On the terminal from PICkit 4, there is a overshoot at least up to 10.15 V
This is still within absolute MAX rating for the chip,
but outside recommended Max.
Other side of the 180 Ohm resistor the voltage is attenuated to about 8.77 V
After about a millisecond for stabilisation, Vpp voltage converge at about 8.75 V
With higher resolution capture of the rising edge,
the overshoot reach 10.8 V
This is still barely within absolute max rating for PIC18__K22 devices.
After the Resistor, Voltage on /MCLR pin stay within recommended range at all time,
and it Debug with no problem.
Note however that the PIC18F26K22 is powered with external +5V.
There is a Compensation issue with the oscilloscope probe used for the red trace in the capture shown in this message, so the overshoot voltage is Not caused by PICkit 4.
post edited by Mysil - 2019/12/20 09:38:50