AD7280a software woes

I am struggling to get data back from an AD7280a. The circuit consists of a single AD7280a monitoring 4 lithium ion cells and 6 thermistors. I am attempting to request a conversion using the rising edge of CS.

As an example I am attempting to retrieve cell voltage 1 thus (pseudo code):


Write 0x1A6151A //turn off read

Write 0x1CD90BA //set acquisition time, specify that a resistor is attached to pin 32, lock device address

Write 0x1A1121A //turn on read

Get voltage 1

Write 0x38011CA //Write to READ register value of register we want to read from

Write 0x1A1121A //Specify conversion from rising edge of CS (again, to be on the safe side)

Send 0xF800030A and read the data returned by SPI

I set CS low before the SPI write then high afterwards

I have checked the value returned by each of the writes. The register addresses returned are all 000000, the register data 0001000 and the write acknowledge zero. The write acknowledge returned from the 0xF800030A  seems to be zero also and the data is meaningless.

Any suggestions gratefully received!