From here I read that the change detection will NOT cache the data, which means the data you read are those when ReadSingleSampleMultiLine or BeginReadSingleSampleMultiLine executed, protentially different from when change raising.
However, according to this,
"Once a change occurs, data is latched in the hardware buffer, and then the pattern is transferred via Direct Memory Access (DMA) or Interrupt to the PC memory."
which is the opposite description. This confused me, which one is true? latched&transfer or not?