Thank you PatrickN and MMA.
I just solved the issue by keeping 1uF near to the 27 the pin (LVDD) along with 400nF which was little far.. Problem was with LVDD only. If I am correct I believe all the problem occurred is just because of the voltage regulation in LVDD.
My observations:
- Since the voltage drop in LVDD, internal Power-on reset was holding device in reset. And I was not able to establish the connection with microcontroller using JTAG (It showed all kind of errors like "Could not find supported CPU core on JTAG chain".)
- I was able to program the device by pressing the RESET switch followed by loading the program- may be initially I got sufficient delay to establish connection before going to POR.
- When I kept some different capacitors it was working randomly - may be ripples in LVDD, voltage may be going down below 2.35V randomly.
- Finally it solved when I kept 1uF along with 400nF near to the LVDD pin.
Thanks for your response
Sijo