Answer:
Multiplexing is done by the use of the analog multiplexer component. Place analog multiplexer component in your top design and right click and select configure to enter the configuration menu of component. In the configuration set the number of channels to the number of channels required to be multiplexed. Connect the multiplexed inputs to the input of the multiplexer and output can connect to the input of the ADC. The multiplexer selection can be done using the AMux_Select() API.
If the user requires to multiplex differential channels into a differential ADC, that can also be achieved by setting the configuration for differential mode in the AMUX component.
Note:
1. AMux component is just a firmware implementation which configures the switches on-the-go. If higher speed is of more importance / if switching between the channels needs to be controlled by some Hardware, use Hardware Mux.
2. In the same way, we can multiplex the Channels to SAR ADC as well in PSoC 5.