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Page 36
Direct RDRAM
K4R881869M
Rev. 0.9 Jan. 2000
Preliminary
.
Figure 39: TPARM Register
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Read/write register.
Reset value is undefined.
TCAS1..0 - Specifies the t
CAS-C
core parameter in
t
CYCLE
units. This should be
“
10
”
(2t
CYCLE
).
TCLS1..0 - Specifies the t
CLS-C
core parameter in
t
CYCLE
units. Should be
“
10
”
(2t
CYCLE
).
TCDLY0 - Specifies the t
CDLY0-C
core parameter in
t
CYCLE
units. This adds a programmable delay to Q
(read data) packets, permitting round trip read delay to
all devices to be equalized. This field may be written
with the values
“
011
”
(3t
CYCLE
) through
“
101
”
(5t
CYCLE
).
Control Register: TPARM
Address: 048
16
0
0
0
0
0
0
0
0
0
0
0
TCAS
TCLS
The equations relating the core parameters to the
datasheet parameters follow:
t
CAS-C
= 2t
CYCLE
t
CLS-C
= 2t
CYCLE
t
CPS-C
= 1t
CYCLE
Not programmable
t
OFFP
= t
CPS-C
+ t
CAS-C
+ t
CLS-C
- 1t
CYCLE
= 4t
CYCLE
t
RCD
= t
RCD-C
+ 1t
CYCLE
- t
CLS-C
= t
RCD-C
- 1t
CYCLE
t
CAC
= 3t
CYCLE
+ t
CLS-C
+ t
CDLY0-C
+ t
CDLY1-C
(see table below for programming ranges)
TCDLY0
011
011
101
100
TCDLY0
011
3t
CYCLE
3t
CYCLE
5t
CYCLE
4t
CYCLE
t
CDLY0-C
3t
CYCLE
010
001
010
010
TCDLY1
000
2
t
CYCLE
1
t
CYCLE
2
t
CYCLE
2
t
CYCLE
t
CDLY1-C
0
t
CYCLE
10
t
CYCLE
9
t
CYCLE
12
t
CYCLE
11
t
CYCLE
t
CAC
8
t
CYCLE
Figure 40: TFRM Register
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Read/write register.
Reset value is undefined.
TFRM3..0 - Specifies the position of the framing point
in t
CYCLE
units. This value must be greater than or
equal to the t
FRM,MIN
parameter. This is the minimum
offset between a ROW packet (which places a device
at ATTN) and the first COL packet (directed to that
device) which must be framed. This field may be
written with the values
“
0111
”
(7t
CYCLE
) through
“
1010
”
(10t
CYCLE
). TFRM is usually set to the value
which matches the largest t
RCD,MIN
parameter (modulo
4t
CYCLE
) that is present in an RDRAM in the memory
system. Thus, if an RDRAM with t
RCD,MIN
= 9t
CYCLE
were present, then TFRM would be programmed to
5t
CYCLE
.
Control Register: TFRM
Address: 049
16
0
0
0
0
0
0
0
0
0
0
0
0
TFRM3..0
Figure 41: TRDLY Register
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Read/write register.
Reset value is undefined.
TCDLY1 - Specifies the value of the t
CDLY1-C
core
parameter in t
CYCLE
units. This adds a programmable
delay to Q (read data) packets, permitting round trip
read delay to all devices to be equalized. This field may
be written with the values
“
000
”
(0t
CYCLE
) through
“
010
”
(2t
CYCLE
). Refer to Figure 39 for more details.
Control Register: TCDLY1
Address: 04a
16
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TCDLY1