GATE EC 2004 Set 1 Q54 — Computer Organization

The $8255$ Programmable Peripheral Interface is used as described below.

1. An A/D converter is interfaced to a microprocessor through $8255.$ The conversion is initiated by a signal from the $8255$ on Port C. A signal on Port C causes data to be strobed into Port A.
2. Two computers exchange data using a pair of $8255 \mathrm{s}$. Port A works as a bidirectional data port supported by appropriate handshaking signals.

The appropriate modes of operation of the $8255$ for (I) and (II) would be