Hello @srini1211, Good Day!
Thank you very much for your interest in our products.
Please consider that when using LPCD on the CLRC663 the host interface (e.g. SPI) is disabled and cannot and shall not be used. In this functionality the reader will have to be calibrated and then enter a standby state, which will be exited if a card is detected. This sequence is described in detail in section 2.1.2 of the AN11145 document. Please refer to said note for further details.
You may also find useful the "NfcrdlibEx6_LPCD_mcux" example included in the NFC Reader Library for the CLRC663. This example demonstrates this functionality using the LPC1769 MCU as a host, but it can work as a starting point in order to get familiar with the functions and API's used for this feature.
For enabling this feature without using the library, some registers of the CLRC663 must be written and read please refer to section 9.14 of the CLRC663 Data Sheet for further details, as well as the Using the RC663 without library app note to see how communication can be done without the library.
My best regards,
Daniel