@Bikram Sir, I have a silly doubt.
Here the question says data transfer is to be done quickly.
We know that DMA initial setup takes time, and also buffer delay is counted.
In interrupt mode, ISR execution takes time.
In programmable I/O these overheads are not counted.
For long run DMA is best, but for single immediate transfer to be perform quickly, isn't programmable I/O is the choice.
We are not talking about wastage of useful CPU time here.
Correct me if I m wrong.