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Hello all,
I would be grateful if anyone can comment on the following :-
Consider a UDMA Data-in burst where the Host and Device decide at the same time to terminate the burst i.e. the Host negates HDMARDY- at the same time as the Device negates DMARQ (I guess this is a valid possibility).
The Host believing it is performing the termination would then wait for tRP (e.g. a minimum of 85 ns for UDMA Mode 5 in the Rev 4b of the Atapi7 spec I have) before asserting STOP. The Device believes it is performing a termination however so the (>85 ns) delay from DMARQ negation to STOP assertion violates the tLI requirement (e.g. 75ns max in the same spec).
I guess the answer is that the Host should check to see whether the Device has negated DMARQ before/whilst it is performing the tRP delay, and if so, abort the tRP delay and immediately assert STOP. Does anyone know whether this is the correct way to handle this condition?
Thanks in advance,
David Humphreys
LSI Logic Europe Ltd Greenwood House London Road Bracknell Berkshire RG12 2UB, England
Tel:+44 (0) 1344 413210
Fax:+44 (0) 1344 413296
