unit3 (1).ppt microprocessor 8086 microprocessor

8086

1. UNIT-III
Pin Diagram Of 8086
Minimum Mode And Maximum Mode Of Operation.
Timing Diagram
Memory Interfacing To 8086 (Static RAM & EPROM).
Need For DMA.
DMA Data Transfer Method.
Interfacing With 8257.

2. Fig 3.1 Pin diagram of 8086

3. Minimum mode of 8086
• When the Minimum mode operation is selected, the 8086 provides
all control signals needed to implement the memory and I/O interface.
Fig 3.2 Minimum mode pin diagram of 8086

4. Fig 3.3 Write cycle timing diagram of 8086 in
Minimum mode

5. 8086 in Maximum mode
Fig 3.4 Maximum mode 8086 system

6. Fig 3.5 General bus operation cycle in Maximum
mode

7. Memory interfacing
Fig 3.6 Address mapping

8. Fig 3.7 Memory interfacing to 8086

9. For the applications that require huge amounts of data
transfer to memory from a magnetic or optical disk a
dedicated hardware device called DMA controller is used.
The DMA controller temporarily borrows the address
bus ,data bus and control bus from the microprocessor and
transfers the data bytes directly from the disk controller to
a series of memory locations.
Some DMA devices even can do memory to memory
transfers.

10. Fig 3.8 Block diagram of DMA Interfacing

11. Fig 3.9 Block diagram that shows DMA data transfer scheme

12. Fig 3.10 Pin diagram of 8257 DMA
controller

14. Fig 3.12 Mode set register Bit format
Fig 3.13 Status register Bit format

15. Table 3.1 8257 Register selection