In polled mode, individual conversions are requested with individual commands. Other commands set the analog outputs or
digital outputs, change input channels, recalibrate the system, or change to scanning mode. The offset correction channel is
designated as channel 7. The full scale calibration channel is designated as channel 6. The six available analog input channels
are called channels 0 through 5. Note that labels on the board itself are 1 through 6, etc. The assumption is that from a
developer or programmer's perspective, zero-based references are more appropriate, but that the user would prefer counting to
start from 1.