12F675 reseting

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.

Code:

#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.

Code:

#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

Re: 12F675 reseting

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

Re: 12F675 reseting

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