12F675 reseting

[Ioannis]

While I was testing the prototype board with a 12F675 chip, touching with the multimeter probe the pin#4 (MCLR and GP3 input) the chip did a reset.

My configuration is set for internal MCLR and Input on GP3.



#config
__CONFIG _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_OFF & _BODEN_ON & _CP_ON
#endconfig

DEFINE OSC 4
DEFINE OSCCAL_1K 1 'Read OscCal value from the last location

GPIO=0
TRISIO = %00011000


Tried then to have MCLR on the pin and it clearly worked as a MCLR pin.


#config
__CONFIG _INTRC_OSC_NOCLKOUT & _WDT_ON & _PWRTE_ON & _MCLRE_ON & _BODEN_ON & _CP_ON
#endconfig


Then again set MCLR to internal and while it seems to be an input pin, it also does a reset sporadically. I'll do connect a resistor to +Vdd but wonder why this happens.

Ioannis

[richard]

gpio3 doesn't have the the same esd protection as the the other gpio pins, a multimeter probe can deliver a good shock to the system

[Ioannis]

This explains why it is working just fine until I touch the pin with the probe. Even though the other probe is already connected to the ground.

Ioannis