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5.5 Ultra DMA Feature Set
C141-E050-02EN 5-83
7) If DSTROBE is negated, the device shall assert DSTROBE within t
LI
after the host has asserted STOP. No data shall be transferred during this
assertion. The host shall ignore this transition on DSTROBE.
DSTROBE shall remain asserted until the Ultra DMA burst is
terminated.
8) If the host has not placed the result of its CRC calculation on DD (15:0)
since first driving DD (15:0) during (6), 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 device has
asserted DSTROBE and negated DMARQ and the host has asserted
STOP and negated HDMARDY-, and no sooner than t
DVS
after the host
places 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 DSTROBE within t
IORDYZ
after the host negates
DMACK-.
13) The host shall not negate STOP no assert HDMARDY- until at least t
ACK
after negating DMACK-.
14) The host shall not assert DIOR-, CS0-, CS1-, DA2, DA1, or DA0 until at
least t
ACK
after negating DMACK.
b) Host terminating an Ultra DMA data in burst
The following steps shall occur in the order they are listed unless otherwise
specifically allowed (see 5.6.4.6 and 5.6.4.2 for specific timing
requirements):
1) The host shall not initiate Ultra DMA burst termination until at least one
data word of an Ultra DMA burst has been transferred.
2) The host shall initiate Ultra DMA burst termination by negating
HDMARDY-. The host shall continue to negate HDMARDY- until the
Ultra DMA burst is terminated.
3) The device shall stop generating DSTROBE edges within t
RFS
of the host
negating HDMARDY-.
4) If the host negates HDMARDY- within t
SR
after the device has generated
a DSTROBE edge, then the host shall be prepared to receive zero or one
additional data words. If the host negates HDMARDY- greater than t
SR
after the device has generated a DSTROBE edge, then the host 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 device.