Apple developed some add-ons for processors like 8085/8086/8088. The add-ons includes
8255 – Parallel Communication Interface (PPI)
8251 – Serial communication Interface (USART- Universal Synchronous/Asynchronous Receiver/Transmitter)
8257 – DMA Controller
8279 – Keyboard/Display Controller
8259 – Programmable Interrupt controller
8254 – Programmable Timer
Kinds of Communication Interface
There’s two ways that a micro-processor can interact with outdoors world or any other memory systems.
Serial Communication Interface
Parallel Communication interface
Serial Communication Interface:
In serial communication interface, the interface will get just one byte of information in the micro-processor and transmits it piece by piece with other system serially (or) the interface receives data piece by piece serially in the exterior systems and converts the information right into a single byte and transfers it towards the micro-processor.
Parallel Communication Interface:
This interface will get a byte of information from micro-processor and transmits it piece by piece to another systems in synchronised (or) parallel fashion. The interface also receives data piece by piece concurrently in the exterior system and converts the information right into a single byte and transfers it to micro-processor.
Consider we have a micro-processor interfaced to both I/O device in addition to a memory nick. Just how to pick backward and forward devices based on the requirement?
For this function a previous address decoding circuit can be used. A previous address decoding circuit helps with choosing the needed I/O device or perhaps a memory nick.
Let’s talk of the idea of Memory interfacing and that iOrTo interfacing within the next article.