Ok.
http://www.sparkfun.com/datasheets/Sensors/Accelerometer/ADXL345.pdf - this is the datasheet from sparkfun of ADXL345 sensor.
Go to page 17, in the top right corner, and you'll see for example register 0x31.
Look at the table: you see D7, D6, D5, D4, D3, D2, D1, D0. Every bit of this byte has a function in this register. (enable and disable).
For example if I want to enable the 3-pin SPI at position D6 I have to send 01000000 code. (in case the other bits are 0's). The equivalent in decimal is 64. But if I want to enable both the SPI and Justify bit I have to send 01000100 which in decimal equals 68.
The problem is that I cannot send the values directly over I2C binary, because the Wire doesn't let me do it. I just can send one value at a time. And the solution is to convert the 8-bit code into a decimal and then print it over I2C. That's why I need a Binary-Decimal convertor. Mine looks ok, but I don't understand why it isn't working.
And...tell me if I say something wrong.
Thank you,
RobertEagle