Connecting the Same Pins to Two Analog Hardware Muxes - KBA89150

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Question: When you connect the same analog pins to the inputs of two Analog Hardware Multiplexer (AMuxHw) components, PSoC® Creator™ throws a build error. Why?

 

Answer:

You cannot connect the same analog pins to the inputs of two AMuxHws for the following reason:

The AMuxHw uses the individual switch at a pin. The following GPIO block diagram shows the digital output path and analog connectivity.

Figure 1. GPIO block diagram

GPIO block diagram

So there is only one digital signal interconnect (DSI) signal associated with one GPIO pin. This DSI signal is generated on the basis of the mux control signal, which in turn will connect a pin to the analog global or analog mux by enabling the switches. If the same pin is connected to two muxes, then two DSI signals will simultaneously try to turn on the same switches. This is not possible so Creator throws a build error. You have to connect different pins as the inputs of the two hardware muxes.