hsabaghianb @ kashanu.ac.ir Microprocessors 1-40
8086 Pin Description
DEN’ (output) : Data Enable. It is LOW when processor wants to
receive data or processor is giving out data (to74245)
DT/R’ (output) : Data Transmit/Receive.
When High, data from uP to memory
When Low, data is from memory to uP (to74245 dir)
IO/M’ (output) : If High uP access I/O Device.
If Low uP access memory
RD’ (output) : When Low, uP is performing a read operation
WR’ (output) : When Low, uP is performing a write operation
ALE (output) : Address Latch Enable , Active High
Provided by uP to latch address
When HIGH, uP is using AD0..AD7, A19/S6,
A18/S5, A17/S4, A16/S3 as address lines