a) ALE:

• It is the output pin of 8086. In is used to latch the address by de-multiplexing (seperate) address and data line from AD0-AD15, A16-A19 and S7/BHE.

b) NMI:

• It is input pin to 8086. This is a non-maskable, edge triggered, high priority hardware interrupt.
• On receiving an interrupt on NMI line, the µP executes INT 2 i.e. and takes control to location 2 x 4 = 00008H in the Interrupt Vector Table (IVT), to get the value for CS and IP.

c) HOLD:

• It is input pin to 8086. In Minimum Mode this line carries the HOLD input signal. The DMA Controller issues the HOLD signal to request for the system bus. In response 8086 completes the current bus cycle and releases the system bus.

d) RESET:

• It is input pin to 8086. This is the reset input signal. The 8284 Clock generator provides it. It clears the Flag register and the Instruction Queue.

• It also clears the DS, SS, ES and IP registers and Sets the bits of CS register. Hence the reset vector address of 8086 is FFFFOH (as CS = FFFFH and IP = 0000H).

e) ¯DEN:

• It is output pin to 8086. It is used to enable the data transceivers (bi-directional buffers - IC 8286).