Pdf 8255 ppi

Every ports of can be programmed to work in mode 0. We call mode 1 as the strobed Input Output or handshake Input Output. It is useful when data is supplied to the input device by the microprocessor at irregular interval of time. Finally, when the data is read by the processor the port informs the Input device that the processors already read the data.

This feature reduces software requirement in control-based applications. This facility is provided only for Port C. Nancy Den. Previous Page Print Page. Next Page. It is an active low input pin for If this pin is at logic 0, the chip is selected for communication with the microprocessor. If the chip is not selected the data lines D of will be in tristate. These pins are the data pins, which are used by for communication with the microprocessor.

They are connected to the data bus of the microcomputer system. These are address-input pins. They select one of the ports inside for communication with the microprocessor. It is an active high input pin. It is connected to ResetOut output of It is used to reset the After a reset of , all the three ports of work as input ports in mode 0, which is the simplest mode of operation. Intel is a peripheral interface PPI chip which is programmable. It is used for the connection of peripheral devices and interfacing.

We call Peripheral device also as Input Output device. We use Input Output ports for the connection of Input Output devices.

Hence is a programmable Input Output port chip. It is a 40 pin chip available for dual line packaging. It consists of two programmable Input Output ports having of size 8 bits and two programmable Input Output ports of size 4 bits. These pins source 1 mA of current at 1. Hence we divide port C into 2 parts having 4 bits. The port selection logic is given where the output is set by us to the logic 1 and we reset it to logic 0.

There are three modes of operation performed by they are as mode 0, mode 1 and mode 2. 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 can be programmed to work in mode 0. We call mode 1 as the strobed Input Output or handshake Input Output.