AD9744 input data format

[happsky]

AD9744 has a "MODE" pin ，and datasheet explains: “Selects Input Data Format. Connect to DCOM for straight binary, DVDD for twos complement”[page 7]，also in datasheet says:“ The 14-bit parallel data inputs follow standard positive binary coding, where DB13 is the most significant bit (MSB) and DB0 is the least significant bit (LSB)”[page 15]。
I think it is contradictory, if twos complement mode is choosed, when MSB is 1, init meas negative, but not positive coding.
when the twos complement mode is choosed,the input range is like{0~16383} or {-8191~8192}? thank you!

AD9744 Datasheet:
https://www.analog.com/media/en/technical-documentation/data-sheets/AD9744.pdf

 

[Aussie Susan]

I think you are "over interpreting" the word "positive" in the phrase "standard positive binary coding".
As far as I can see, if the MODE pin is set to 'straight binary', the you can present an unsigned value from 0 to 16383 to the input pins.
If the MODE pin is set to 'two's complement' then you present a signed value from -8192 to +8191 with, as you say, the MSB is 1 to indicate a negative number and 0 to indicate a positive number.
Susan