I’m working on building a 40% keyboard which has a 12×4 layout, and the firmware for now just need to support one key at a time.
The key scanning function returning a single integer, so I need to pack the two values
Row of a pressed key into this integer.
Since both of the column and row values are quite small (less than 255), I can just use two bytes to represent them. Therefore, I can pack them into an integer easily by using bit shift operators. Put the row value to the 8 low bits, and the rest is for the column value.
RESULT: int = (COL << 0) | (ROW << 8)
Later on in key sending logic, I can extract them all by shifting it back again:
COL: byte = (RESULT >> 0) ROW: byte = (RESULT >> 8)