The 8086 processor provides 16 data lines but the memory chip will consist of only 8 data lines therefore to occupy all system data lines of processor we require to memory chips.
One of them will be connected to lower order Data bus (D0 to D7) and other will be connected to higher order Data bus (D8 to D16). The total memory required in a system will be divided into two parts. All the locations in part one will have even addresses and if it is connected to D0 to D7 of processor. This part is known as Even bank.
Similarly all the locations in part two will have odd addresses and it is connected to D8 to D15. This banking scheme allows to have same addresses for two parallel bytes and process can perform 16 bit data transfer.
The least Significant bit of address (A0 is not used for byte selection)it is reserved for bank selection. Therefore A0=0 will select Even bank. The BHE signal is used for selection of odd bank.the processor will used combination of this two signals decide type of data transfer.
|BHE||A0||types of Transfer|
|1||0||8 bit data transfer from even address through D7 to D0|
|0||1||8 bit data transfer from odd address through D15 to D8|
|0||0||16 bit data transfer from even address through D15 to D0|
|1||0||16 bit data transfer fron odd addresses through D15 to D0|
In this case the first machine cycle generates odd address (A0=1) transfer lower order 8 data bits on higher order data bus.In second machine cycle higher order data bus will be transfer on lower order data bus.
- Cache Organization | Set 1 (Introduction)
- Computer Organization | Cache Memory
- Computer Arithmetic | Set - 1
- Computer Arithmetic | Set - 2
- Computer Organization and Architecture | Pipelining | Set 1 (Execution, Stages and Throughput)
- Computer Organization and Architecture | Pipelining | Set 3 (Types and Stalling)
- Computer Organization and Architecture | Pipelining | Set 2 (Dependencies and Data Hazard)
- Computer Organization | Amdahl's law and its proof
- Different Types of RAM (Random Access Memory )
- Computer Organization | Hardwired v/s Micro-programmed Control Unit
- Computer Architecture | Flynn's taxonomy
- Computer Organization | Multiplication Algorithm in Signed Magnitude Representation
- Clusters In Computer Organisation
- Generations of Computer
- Simplified Instructional Computer (SIC)
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.