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5.5 Ultra DMA Feature Set
C141-E050-02EN 5-85
5.5.4 Ultra DMA data out commands
5.5.4.1 Initiating an Ultra DMA data out burst
The following steps shall occur in the order they are listed unless otherwise
specifically allowed (see 5.6.4.7 and 5.6.4.2 for specific timing requirements):
1) The host shall keep DMACK- in the negated state before an Ultra DMA burst
is initiated.
2) The device shall assert DMARQ to initiate an Ultra DMA burst.
3) Steps (3), (4), and (5) may occur in any order or at the same time. The host
shall assert STOP.
4) The host shall assert HSTROBE.
5) The host shall negate CS0-, CS1-, DA2, DA1, and DA0. The host shall keep
CS0-, CS1-, DA2, DA1, and DA0 negated until after negating DMACK- at
the end of the burst.
6) Steps (3), (4), and (5) shall have occurred at least t
ACK
before the host asserts
DMACK-. The host shall keep DMACK- asserted until the end of an Ultra
DMA burst.
7) The device may negate DDMARDY- t
ZIORDY
after the host has asserted
DMACK-. Once the device has negated DDMARDY-, the device shall not
release DDMARDY- until after the host has negated DMACK- at the end of
an Ultra DMA burst.
8) The host shall negate STOP within t
ENV
after asserting DMACK-. The host
shall not assert STOP until after the first negation of HSTROBE.
9) The device shall assert DDMARDY- within t
LI
after the host has negated
STOP. After asserting DMARQ and DDMARDY- the device shall not
negate either signal until after the first negation of HSTROBE by the host.
10) The host shall drive the first word of the data transfer onto DD (15:0). This
step may occur any time during Ultra DMA burst initiation.
11) To transfer the first word of data: the host shall negate HSTROBE no sooner
than t
LI
after the device has asserted DDMARDY-. The host shall negate
HSTROBE no sooner than t
DVS
after the driving the first word of data onto
DD (15:0).
5.5.4.2 The data out transfer
The following steps shall occur in the order they are listed unless otherwise
specifically allowed (see 5.6.4.8 and 5.6.4.2 for specific timing requirements):
1) The host shall drive a data word onto DD (15:0).
2) The host shall generate an HSTROBE edge to latch the new word no sooner
than t
DVS
after changing the state of DD (15:0). The host shall generate an