What do you mean single and double handshaking of microprocessor 8086?
They are the ways of transmitting parallel data to the
microprocessor.
In single handshake, a peripheral device first sends a "Strobe
signal" to the microprocessor to indicate that it is ready to send
data. The microprocessor , upon detecting the strobe signal, opens
up its input port and receives the data. After receiving data, it
sends an "Acknowledge signal" to the peripheral to indicate that
transmission has been completed.A transmission session has been
completed.
In double handshake, first the peripheral device sends a strobe
signal, the microprocessor, sends the acknowledge signal to
indicate that it is ready to receive data. After which data is
received.After sending data, the peripheral sends a strobe signal
to indicate data transmission completion, due to which, the
microprocessor drops its acknowledge signal and a session has been
completed.
The only difference in the two is that, in double handshake, the
peripheral is informed about the microprocessor's readiness to
receive data. This is doesn't happen in single handshake. So the
name follows "double handshake", literally meaning "double
confirmation".