Hi all

I have been designing a weightmatic filler by ADUC812BS and AD7730 ADC. I have eight AD7730 on the board.
I have some problems with SPI bus. I can write to AD7730 but can't read from this because (dout) of AD7730 remains in tristate (CS=0 & POL=0).
Sometimes it becomes high or low after writing some bytes.
I have some exception.at the first time for reading of status register
if I write 10h and ffh then content of SPIDAT becomes equal to
status register ( cfh ).( in fact for reading I write ffh)
At the first loop content of SPIDAT becomes cfh if I write 10h and 80h.
but in the next DOUT goes to tristate.
in reading 16 bit (for example mode register) I can only read first byte
correctly.
I have no write collision in ADUC812 by using adequate NOP instructions between two writes. Would you please tell me what shall I do for solving this problem.

Thanks in advance.

javidi