After the ACK signal is false, the target may continue the transfer by driving the DB(7>0, P) signals and asserting the REQ signal, as previously described.
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BSY
SEL
C/D, MSG
I/O
REQ
ACK
DB
b.Asynchronous transfer from initiator to target
If the I/O signal is false (transfer to the target), the target shall request information by asserting the REQ signal. The initiator shall drive the DB(7>0, P) signals to their desired values, delay at least one deskew delay plus a cable skew delay then assert the ACK signal. The initiator shall continue to drive the DB(7>0, P) signals until the REQ signal is false. When the ACK signal becomes true at the target, the target shall read the DB(7>0, P) signals then negate the REQ signal. When the REQ signal becomes false at the initiator, the initiator may change or release the DB(7>0, P) signals and shall negate the ACK signal. The target may continue the transfer by asserting the REQ signal, as previously described.
4 $ 19