The binary was just an example. I wrote that in the comment section.
I'll give you just an example:
In the datasheet there is a register called 0x32, and that register can hold 8 bits.
The 1st and the 2nd bit is for Mode selecting(4 modes. 00/01/10/11).
Then the 3rd bit is for trigger.(0/1)
And then the other 4 bits are for other input.(0000...1111)
The communication is made over I2C and it is an ADXL345, as I said earlier.
The idea is that in my Arduino I select what I have to, transform all the values into a binary one, and then send them over I2C as a decimal.
If there's another option I'm glad hear it. (I don't want to use other's library)
Thank you,
RobertEagle