Which of the ports in 8255, in which part of the port pins can be used as input lines and part of the port pines can be used as output lines ?
UGC NET - 2012,
Answer: C
Port C of the 8255 can be split into two halves of four lines each, called upper C and lower C, and the two halves can be set independently, one as input and the other as output. The 8255 has three 8-bit ports, A, B and C, and no port D, so that option does not exist. Ports A and B are each set as a whole port for input or output in the modes of operation, so part of the pins of those ports cannot be input while the rest are output. The answer is PC.
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