This is supposed to be general knowledge, but I still see many companies’s making the same mistake.
1. Fit a 100nF cap (surface mount if you can) close to the DS1232.
DS1232 does NOT react well to noise on the supply, the following symptoms may appear in your system.
1. Micro start – up correctly at power - up
2. The external reset (if fitted) does not work.
3. Micro seems to “CRASH” and not recover.
4. Watchdog not resetting Micro.
5. System generate excessive heat
6. After power – down – up, system is ok

It seems as if noise disables or hang the DS1232 and only the power detection still works. If you can spare the cost a 10uH coil inline with the supply will help.