Each ADC has 16 programmable channels that can be independently programmed for analog-to-digital conversion when corresponding bits in the SAMPLEMODE register are set to Sequential Mode. For example, if bit 2 in the SAMPLEMODE register is set to 0, ADC channels 4 and 5 are set to sequential mode. Both the SOC4CTL and SOC5CTL registers can then be programmed to configure channels 4 and 5 to independently perform analog-to-digital conversions with results being stored in the RESULT4 and RESULT5 registers. "Independently" means that channel 4 may use a different SOC trigger, different analog input, and different sampling window than the trigger, input, and window assigned to channel 5.
The 16 programmable channels for each ADC may also be grouped in 8 channel pairs when corresponding bits in the SAMPLEMODE register are set to Simultaneous Mode. For example, if bit 2 in the SAMPLEMODE register is set to 1, ADC channels 4 and 5 are set to Simultaneous Mode. The SOC4CTL register now contains configuration parameters for both channel 4 and channel 5, and the SOC5CTL register is ignored. While channel 4 and channel 5 are still using dedicated analog inputs (now selected as pairs in the CHSEL field of SOC4CTL), they both share the same SOC trigger and Sampling Window, with the results being stored in the RESULT4 and RESULT5 registers.
The Simultaneous mode is made possible by two sample-and-hold units present in each ADC. Each sample-and-hold unit has its own mux for selecting analog inputs (see Figure 5-11). By programming the SAMPLEMODE register, the 16 available channels can be configured as 16 independent channels, 8 channel pairs, or any combination thereof (for example, 10 sequential channels and 3 simultaneous pairs).