Dear Raghunathan,

up to today I never had problems with DS1232. But since some forum members reported about hang-ups of this chip I do prefer MAX1232. May be you now also suffer from this story?

DS1232 seems to be a bit susceptible against ground noise and power supply noise. Means, if fast glitches run over the board near DS1232 they tend to hang-up...

I would recommend you to insert a power supply filter of let's say 10Ohm plus 10µF Tantal. This would at least remove glitches from power supply pin. But ground noise which results from ground bounce e.g. can only be kept under control when using solid ground plane. May be it's a good idea to standardly use 89C51RD2 in combination with four layer board to guarantee minimal ground noise...

Have you had a look at ALE pulses? Do they look good, in terms of ringing and edges? ALE signal should not have to run a long distance to DS1232.

Good luck,
Kai