AT INTERFACE DESCRIPTION
5 – 5
Ultra DMA Timing
TIMING PARAMETERS
(all times in nanoseconds)
MODE 0
MODE 1
MODE 2
MODE 3
MODE 4
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
MIN
MAX
t
CYC
Cycle Time (from STROBE edge to STROBE edge)
112
73
54
39
25
t2
CYC
Two cycle time (from rising edge to next rising edge or
from falling edge to next falling edge of STROBE)
230
154
115
86
57
t
D S
Data setup time (at recipient)
15
10
7
7
5
t
DH
Data hold time (at recipient)
5
5
5
5
5
t
DVS
Data valid setup time at sender (time from data bus being
valid until STROBE edge)
70
48
30
20
6
t
DVH
Data valid hold time at sender (time from STROBE edge
until data may go invalid)
6
6
6
6
6
t
F S
First STROBE (time for device to send first STROBE)
0
230
0
200
0
170
0
130
0
120
t
L I
Limited interlock time (time allowed between an action by
one agent, either host or device, and the following action
by the other agent)
0
150
0
150
0
150
0
100
0
100
t
MLI
Interlock time with minimum
20
20
20
20
20
t
U I
Unlimited interlock time
0
0
0
0
0
t
A Z
Maximum time allowed for outputs to release
10
10
10
10
10
t
ZAH
Minimum delay time required for output drivers turning on
(from released state)
20
20
20
20
20
t
ZAD
0
0
0
0
0
t
ENV
Envelope time (all control signal transitions are within the
DMACK envelope by this much time)
20
70
20
70
20
70
20
55
20
55
t
S R
STROBE to DMARDY (response time to ensure the
synchronous pause case when the recipient is pausing)
50
30
20
NA
NA
t
RFS
Ready-to-final-STROBE time (no more STROBE edges
may be sent this long after receiving DMARDY- negation)
75
70
60
60
60
t
R P
Ready-to-pause time (time until a recipient may assume
that the sender has paused after negation of DMARDY-)
160
125
100
100
100
t
IORDYZ
Pull-up time before allowing IORDY to be released
20
20
20
20
20
t
Z I O R D Y
Minimum time device shall wait before driving IORDY
0
0
0
0
0
t
ACK
Setup and hold times before assertion and negation of
DMACK-
20
20
20
20
20
t
S S
Time from STROBE edge to STOP assertion when the
sender is stopping
50
50
50
50
50
DMARQ
(device)
DMACK-
(host)
STOP
(host)
HDMARDY-
(host)
DSTROBE
(device)
DD(15:0)
t
ZAD
DA0, DA1, DA2,
CS0-, CS1-
t
UI
t
ZAD
t
ACK
t
ACK
t
ENV
t
ENV
t
ZIORDY
t
FS
t
FS
t
VDS
t
AZ
t
DVH
t
ACK
Figure 5 - 4
Initiating an Ultra DMA Data In Burst
