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5-88 C141-E050-02EN
b) Device terminating an Ultra DMA data out burst
The following steps shall occur in the order they are listed unless otherwise
specifically allowed (see 5.6.4.11 and 5.6.4.2 for specific timing
requirements):
1) The device shall not initiate Ultra DMA burst termination until at least
one data word of an Ultra DMA burst has been transferred.
2) The device shall initiate Ultra DMA burst termination by negating
DDMARDY-.
3) The host shall stop generating an HSTROBE edges within t
RFS
of the
device negating DDMARDY-.
4) If the device negates DDMARDY- within t
SR
after the host has generated
an HSTROBE edge, then the device shall be prepared to receive zero or
one additional data words. If the device negates DDMARDY- greater
than t
SR
after the host has generated an HSTROBE edge, then the device
shall be prepared to receive zero, one or two additional data words. The
additional data words are a result of cable round trip delay and t
RFS
timing
for the host.
5) The device shall negate DMARQ no sooner than t
RP
after negating
DDMARDY-. The device shall not assert DMARQ again until after the
Ultra DMA burst is terminated.
6) The host shall assert STOP with t
LI
after the device has negated DMARQ.
The host shall not negate STOP again until after the Ultra DMA burst is
terminated.
7) If HSTROBE is negated, the host shall assert HSTROBE with t
LI
after
the device has negated DMARQ. No data shall be transferred during this
assertion. The device shall ignore this transition of HSTROBE.
HSTROBE shall remain asserted until the Ultra DMA burst is
terminated.
8) The host shall place the result of its CRC calculation on DD (15:0) (see
5.5.5).
9) The host shall negate DMACK- no sooner than t
MLI
after the host has
asserted HSTROBE and STOP and the device has negated DMARQ and
DDMARDY-, and no sooner than t
DVS
after placing the result of its CRC
calculation on DD (15:0).
10) The device shall latch the host's CRC data from DD (15:0) on the
negating edge of DMACK-.
11) The device shall compare the CRC data received from the host with the
results of its own CRC calculation. If a miscompare error occurs during
one or more Ultra DMA bursts for any one command, at the end of the
command, the device shall report the first error that occurred (see 5.5.5).
12) The device shall release DDMARDY- within t
IORDYZ
after the host has negated
DMACK-.