Ed's quick and easy tip to wrap your head around CV29: Think of it as a bank of 8 toggle switches and NOT as a real number that can be adjusted like a volume control knob. Inside CV29, each bit has a unique meaning. Here is a listing of the bit meanings:
Bit 0 ON  = Direction of operation is reversed
OFF  = Direction of operation is normal
Bit 1 ON  = 28 Speed Step Mode (should always be enabled)
Bit 2 ON  = Analog mode operation enabled
OFF  = Analog mode disabled
Bit 3 is Railcom and is usually ignored by the DCC system firmware.
Bit 4 ON  = Alternate Speed Curve Active OFF  = Use table defined by CV 2, 5 and 6
Bit 5 ON  = Use long address in CV17/18 OFF  = Use short address defined in CV1
Bits 6 and 7 are ignored by the DCC system firmware.
Now to transfer the state of all of the individual bits as a single numeric value is where the confusing part comes into play. What is required is a little binary mathematics to calculate the final numeric value but even that is pretty easy once you know how to do it. First, start by reading a bit string from right to left. As you move to each successive bit to the left, you will notice that the bit value doubles from the previous bit value.
I found this really useful CV29 tool online