Changes

In this mode , the 8 bit port A (PA0-PA7) of 8255 IC ports can be configured as input or output portused for simple I/O operations without handshaking signals. In the similar fashion Port A, port B (PB0-PB7) can also configured as input or output provide simple I/O operation. However there is flexibility for the The two halves of port C. It can be divided into two either used together as an additional 8-bit port, or they can be used as individual 4 -bit ports, . Since the two halves of port CLower (PC0-PC3) and port CUpper (PC4-PC7). Each of them can set independently for input or output operation. In this way we can say there C are four ports (port-Aindependent, portthey may be used such that one-B, port CLower and port CUpper) and each of them can set either half is initialized as an input port or while the other half is initialized as an output port. Here these ports are simple input or output ports. That means these ports can work without handshaking. In this mode the outputs are latched whereas the inputs are not latched.