Data & Address Control in 8088

These weeks, we have learned more detailed knowledge about microprocessor. We focus on how the microprocessors control address and data and how these different microprocessors work together and achieve some purposes.

Actually, we use 8088--the most widely used microprocessor as an example to learn in detail.

The following graph is the picture of 8088 Fully Buffered Buses. We can see it can work in 2 different modes--Minimum mode and Maximum mode(as in the following picture, it works in minimum mode).Some buses are address buses and some are data buses and some are even can be used as both address and data buses, using multiplexing method.Information is transferred in both directions on the data bus - hence the data bus buffer must be bidirectional. A bidirectional buffer has a “direction”, which is controlled by (DIR) input.

We also learned the Basic 8086 System Timing(8086 is similar to 8088). Now, I can understand clearly how different pins work together and activate each other one by one in sequence by referring to the following diagram.

One special thing and difficult part to learn is about READY pin and WAITING. At first, I can't get the point and didn't know why it is needed and how it works. However, after reviewing the notes again and again and discussing with classmates and professor, I begin to get it and find it a really important and innovative design! The creative designer considered the situation that the access time for a memory device is longer than the memory

access time calculated,then we need to give extra clock periods, wait state

Tw, for memory, to guarantee the microprocessor works well. 

And we also see a macro-scope picture about how different microprocessors connect with each others and work together to achieve some purpose. We should not only know how a single microprocessor works, we also need to know the relationship between different microprocessors. Only in that way can we learn it well and use them properly and design our own system. 

Anyway, I feel this course is getting more and more difficult, but more and more interesting as well. There are a lot of scattered and seemingly unrelated knowledge that need to be learned and remembered. But what is more important, we have to be clear about those tedious information and put them in order and find out their relationship and regard it as a whole system. We have to build our own map about those pieces of knowledge. That like: knowledge is like pieces of bricks, what we should do is not only collect them, but using them to build our own houses!

Actually, my partner and I are trying to do a mini-project using the knowledge we have learned. We hope to make a smart car model which can follow the route automatically and even response to the change of the environment and give some information and tips about it. We have written down out proposal and drew the graph, and it is expected to be finished by the end of November.

This our design:

I hope we can make it out and make it even better than we expected!

We will try our best!