Found 6 Articles for 8255

In 8255, there are two types of command words or control word are available. And they are −Mode definition control word andPort C bit set/reset control word.Both these are written to the control port only. From the point of view of the microprocessor there is a single 8-bit control port, which is selected when CS* = 0, WR* = 0, A1 = 1 and A0 = 1. But if we consider the architecture of 8255, internally there are two control ports, one for mode definition control and another for Port C bit set/reset control. The contents of the control port ... Read More

There are three modes of operation which are supported by 8255. We call them as mode 0, mode1 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 8255 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 ... Read More

Intel 8255 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 8255 is a programmable Input Output port chip. It is a 40 pin chip available for dual line packaging. Power supply of +5 Volt DC is needed for its working. It consists of two programmable Input Output ports having of size 8 bits and two programmable Input Output ports of size 4 bits. We call them ... Read More

The 8255 is a general purpose programmable IO device. It is designed to interface the CPU with some external devices like ADC, DAC, keyboard etc. We can program the device according to the given condition.There are three 8-bit bi-directional IO ports. The Port-A, Port-B, and Port-C. These ports are assigned as input or output port.The block diagram of 8255 is like this:There are two different modes of 8255. These modes are:Bit Set Reset (BSR) ModeInput/ Output ModeBit Set Reset (BSR) ModeThis mode is used to set or reset the bits of the Port-C only. For BSR mode always D7 will ... Read More

In this program we will see how to perform subtraction by using ports to take data and send the result into the port.Problem StatementWrite 8085 Assembly language program for interfacing between 8085 and 8255. Here Port A and Port B are holding two values, take the numbers from port A and B, subtract B from A, and send the result at port C.DiscussionThe task is very simple. At first we have to setup the control word register of 8255 chip. After that we will take the input from port A and B, add the content, and send it to port ... Read More

Intel 8255 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 8255 is a programmable Input Output port chip. It is a 40 pin chip available for dual line packaging. Power supply of +5 Volt DC is needed for its working. It consists of two programmable Input Output ports having of size 8 bits and two programmable Input Output ports of size 4 bits. We call them ... Read More