fi matlab fixed point conversion of negative number

Hello everyone,

I recently bumped on a peculiar issue that puzzles me. I am using fi for fixed point conversion,that i am trying to do is to use the function for converting a negative floating point number to unsigned fixed point. For exapmle:

input=[0.7070   -0.7070];
fixed_point_input=hex(fi(input(1),0,32,27))

fixed_point_input =
05a7ef9e

and then:

fixed_point_input=hex(fi(input(2),0,32,27))

fixed_point_input =

00000000

Any recommendations on how to perform conversion to unsigned having as input negative floating point? Regards George