Bitwise un-Gray

Converts a reflected Gray code value back into a normal binary number — the inverse of Bitwise Gray.

Why you need this. Many rotary encoders, absolute shaft encoders and linear position sensors output their position as Gray code rather than plain binary. Gray code is designed so that only one bit ever changes between adjacent positions, which prevents the sensor from being misread while its bits are switching (see Bitwise Gray for the full explanation). The trade-off is that the raw Gray value is not the position number — for example the Gray reading 110 actually means position 4, not 6. This module performs the decoding so you get back the real position you can compute with.

Notice the raw Gray readings look scrambled (011, 010, 110, 111), but after un-Gray they come out as the clean sequence 2, 3, 4, 5.

Settings

in

Input value.

out

Output value.

Example — reading a rotary encoder

A 4-bit absolute rotary encoder is wired to Usine as four on/off inputs (one per encoder track). As the shaft turns it emits Gray code. To convert that raw signal into a usable 0–15 position, chain:

4 encoder bits  ->  [Bitwise Bit Array to Bitwise]  ->  [Bitwise un-Gray]  ->  [Bitwise to Integer]  ->  position 0..15

Turning the shaft one detent at a time, the raw bits and the decoded position look like this:

Only one physical track flips at each step (0001→0011→0010→0110), so the reading never glitches, yet the decoded position advances cleanly 0, 1, 2, 3, 4. Feed that position into a fader, a selector, or any parameter you want the knob to control.

See also

• Bitwise
• Bitwise XNOR
• Bitwise to String
• Bitwise Constant
• Bitwise un-Gray
• Bitwise MULT
• Bitwise SHR
• Bitwise MOD
• Bitwise ROL
• Bitwise SUB
• Bitwise NAND
• Bitwise ADD
• Bitwise to Bit Array
• Bitwise Set Bit
• Bitwise String to Bitwise
• Bitwise to Integer
• Bitwise NOR
• Bitwise Reverse
• Bitwise LSB
• Bitwise AND
• Bitwise Gray
• Bitwise Field
• Bitwise DIV
• Bitwise Mask
• Bitwise OR
• Bitwise Integer to Bitwise
• Bitwise Get Bit
• Bitwise CRC32
• Bitwise Bit Array to Bitwise
• Bitwise SHL
• Bitwise Counter
• Bitwise NOT
• Bitwise XOR
• Bitwise MSB
• Bitwise Swap Bytes
• Bitwise ROR
• Bitwise Pop Count