5.5 Ultra DMA Feature Set
C141-E192-01EN
5-123
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.
5)
The host shall assert STOP no sooner than t
RP
after negating
HDMARDY-. The host shall not negate STOP again until after the Ultra
DMA burst is terminated.
6)
The device shall negate DMARQ within t
LI
after the host has asserted
STOP. The device shall not assert DMARQ again until after the Ultra
DMA burst is terminated.
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)
The device shall release DD (15:0) no later than t
AZ
after negating
DMARQ.
9)
The host shall drive DD (15:0) no sooner than t
ZAH
after the device has
negated DMARQ. For this step, the host may first drive DD (15:0) with
the result of its CRC calculation (see 5.5.5).
10) If the host has not placed the result of its CRC calculation on DD (15:0)
since first driving DD (15:0) during (9), the host shall place the result of
its CRC calculation on DD (15:0) (see 5.5.5).
11) 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).
12) The device shall latch the host's CRC data from DD (15:0) on the
negating edge of DMACK-.
13) 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 burst for any one command, at the end of the
command, the device shall report the first error that occurred (see 5.5.5).
14) The device shall release DSTROBE within t
IORDYZ
after the host negates
DMACK-.
15) The host shall neither negate STOP nor assert HDMARDY- until at least
t
ACK
after the host has negated DMACK-.
16) The host shall not assert DIOR-, CS0-, CS1-, DA2, DA1, or DA0 until at
least t
ACK
after negating DMACK.
Summary of Contents for MHT2020AT
Page 1: ...C141 E192 01EN MHT2080AT MHT2060AT MHT2040AT MHT2030AT MHT2020AT DISK DRIVES PRODUCT MANUAL ...
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Page 62: ...Theory of Device Operation 4 10 C141 E192 01EN Figure 4 4 Read write circuit block diagram ...
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Page 191: ...5 4 Command Protocol C141 E192 01EN 5 117 g d f f d e Figure 5 7 Normal DMA data transfer ...
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