MICROPROCESSOR AND MICROCONTROLLER

Detailed explanation-1: -Explanation: In the I/O mode, the 8255 ports work as programmable I/O ports. Explanation: In BSR (Bit Set-Reset) Mode, port C can be used to set and reset its individual port bits. Explanation: In mode 0, any port can be used as input or output and output ports are latched.

Detailed explanation-2: -The 8255 gives a CPU or digital system access to programmable parallel I/O. The 8255 has 24 input/output pins. These are divided into three 8-bit ports (A, B, C). Port A and port B can be used as 8-bit input/output ports.

Detailed explanation-3: -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-4: -We call the mode 0 as the simple Input Output or the basic Input Output for performing the simplest mode of operation. Every ports of 8255 can be programmed to work in mode 0. We call mode 1 as the strobed Input Output or handshake Input Output.

Detailed explanation-5: -i) Mode 0: Simple Input-Output Mode or IO without Handshake. No port, in this case, performs the handshaking function and all the ports, i.e. port A, port B and port C act as an Input-Output port for transferring the data. ii) Mode 1: I/O with Handshake or Strobed I/O. iii) Mode 2: Bidirectional I/O. 22-Aug-2019