Hi all at Forum,

1) I am using Atmel 89c52 for our embedded applicatins. We have abserved that system hangs when there is present heavy mains disturbunce like contactors switching . I am interested to know. what exactly happens to a microcontroller that it loses its track of activity and hangs. Whether it is because power glitch at vcc causes some malfunctioning. Or it is because power glitch causes reset pin to get activated and then not recover properly? Or it is EMI / RFI causing the havoc by modigying registers or SFRs just internally! Is there any article in which these possibiities are discussed? Or may I request experts in this forum to give some clues.

2) I am from India. I would like to know that what cheaper devices are available in India with WDT. At present I am using Atmel 89c52 for our embedded applicatins. Or what is the popular external chip for WDT use, easily available in India. What might be the prices of 89c55, which I understand, is having a WDT, in India. Also an equivalent device from Philips or Cygnal also may help.

Best Regars and thanks.

Mahesh Vyas.