Hi Vikram,
Unfortunately I do not have any example code for the ADS1243. Once the device has been properly connected with respect to supplies, communication, reference, clock, etc., you need to configure the ADS1243 for the desired operation. You do this by writing to the registers where the descriptions are given starting on page 15 of the datasheet.
To read and write to the ADS1243 you must adhere to the timing specifications given in the timing diagram shown on page 6 of the datasheet. The one specifiation that is often missed is the t6 timing, where the command sent must have sufficient time to decode before reading or sending data. Also, CS is required to be low throughout the entire communication transaction.
The best way to determine if the conversion has completed and the results are ready to read is by using the DRDY pin. When DRDY transitions from high to low, the results have been updated and the data is ready to be read from the device.
Best regards,
Bob B