MICROPROCESSOR 8255
ARCHITECTURE OF 8085
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
Port A
|
|
|
Port B
|
|
|
Port C
|
|
|
Port D
|
Detailed explanation-1: -Port C upper is used for the generation of handshake lines in mode 1 or mode 2.
Detailed explanation-2: -Mode 1 – Handshake or Strobed I/O In this mode the Port A and Port B can be used as input or output ports, the port C are used for handshaking. In this mode the inputs and outputs are latched. This mode also has the interrupt handling capability, and signal control to match the speed of CPU and IO devices.
Detailed explanation-3: -Mode 2 − In this mode, Port A can be configured as the bidirectional port and Port B either in Mode 0 or Mode 1. Port A uses five signals from Port C as handshake signals for data transfer. The remaining three signals from Port C can be used either as simple I/O or as handshake for port B.