hi, i am facing some problem on interfacing cs5534.this adc is interfaced to the microcontroller(PIC16F8772) through SPI.i am able to reset the internal logics of the adc and also able to read and write in to any of the internal registers like configuration register ,gain registers ,offset registers or chip select registers. any command related to read or write is working.But it not able to do any calibration or conversion. After a single conversion the adc should bring its SDO pinn LOW, but its never happening.if i ignore these pin state and read the conversion value,it is 0x0000000. same thing is happening in the case of self calibration(made VRS bit in confiuration register is 1 while doing self calibration).SDO pin is not becoming LOW after giving the command for self calibration. the following are the specification of the circuit. Vref=-2.5 V to +2.5V AIN1+ and AIN-=between -2.5 to 2.5V CLOCK=4.9152 mhz crystel A0,A1 pins are not used.(open) supply volt=5V only channel 1 is used(AN1+ and AN1-).all other channel pins are open(not connected).please help me to resolve this problem. thanks, faslu rahman