Destination initiated handshaking vs source initiated handshaking in asynchronous data transfer-:

[shivajikobardan]

In destination initiated handshaking-:
1) Disable ready for data
2) Disable data valid

That means first destination says "I received data totally". Then source stops sending data.

In source initiated handshaking-:
1) Disable data valid
2) Disable data accepted.

That means first source stops sending data, then destination says "I have received data totally"

Source-: https://cvbl.iiita.ac.in/sks/coa-files/lectures/Lec_11_IO[1].pdf

Why are these 2 different order from each other?

 

[Harald Kapp]

That means first destination says "I received data totally". Then source stops sending data.

No. It means the destination signals that it is ready for data or not. There is no indication of date having been received completely.. For example the destination may have a receive buffer and signals "not ready for data" when the buffer is full, regardless of any data still waiting to be sent by the source.