in ADSP-SC58x, HADC provides 8 channels which can be sampled sequentially. If more channels are desired, HADC provides an option to extend the number of channels to 15 by using the external multiplexer. To do this channel 8 of ADC is extended to 8 more additional channels via multiplexer which is controlled through 3 mux pins. For the code, the data from additional channels is stored in HADC DATA registers similar to how it is stored for default channels. There are 15 DATA register each for one HADC channel.