FAIL TO READ DEVICE SIGNETURE OF LPC2468 using FLASH MAGIC

-I have my own PCB for LPC2468 i amtrying to program the LPC using FLASH MAGIC utility but i am getting message FAILED TO RAD DEVICE SIGNETURE.

-to work out the problem i have just provided only powersupply,externel crystal,JTAG and UART (max232) connection, i have ensured the power supply and RS232 signal, but still i am not able to read the device signeture.

-suggest me the solution , i have also tried to debug from JTAG and triesd to write IOPIN register but its not writing.[/b]