Can the serial input of a parallel input/serial output shift register, such as the 74LS165N, be used as an additional input as it were a 9 input shift register?
If it works, I think the input would be read at a slightly later time, but for reading switches, would that matter?
Yes, for reading switches, you could do that. After a parallel load operation, the first 8 bits would come from the switches connected to the parallel inputs, and then all of the bits after that would come from the ninth switch.
Of course, you could connect another shift register to that input and read an additional 8 switches, for a total of 16 or 17 switches.
