K4R881869M Datasheet, PDF (56/64 Pages) Samsung semiconductor – 288Mbit RDRAM 512K x 18 bit x 2*16 Dependent Banks Direct RDRAMTM

K4R881869M
Timing Parameters
Preliminary
Direct RDRAM^™
Table 22: Timing Parameter Summary
Min
Parameter Description
-45
-800
t_RC
Row Cycle time of RDRAM banks -the interval between ROWA packets
28
with ACT commands to the same bank.
t_RAS
RAS-asserted time of RDRAM bank - the interval between ROWA packet
20
with ACT command and next ROWR packet with PRER^a command to the
same bank.
t_RP
Row Precharge time of RDRAM banks - the interval between ROWR packet 8
with PRER^a command and next ROWA packet with ACT command to the
same bank.
t_PP
Precharge-to-precharge time of RDRAM device - the interval between suc-
8
cessive ROWR packets with PRER^a commands to any banks of the same
device.
t_RR
RAS-to-RAS time of RDRAM device - the interval between successive
8
ROWA packets with ACT commands to any banks of the same device.
t_RCD
RAS-to-CAS Delay - the interval from ROWA packet with ACT command
9
to COLC packet with RD or WR command). Note - the RAS-to-CAS delay
seen by the RDRAM core (t_RCD-C) is equal to t_RCD-C = 1 + t_RCD because of
differences in the row and column paths through the RDRAM interface.
t_CAC
t_CWD
t_CC
CAS Access delay - the interval from RD command to Q read data. The
8
equation for t_CAC is given in the TPARM register in Figure 39.
CAS Write Delay (interval from WR command to D write data.
6
CAS-to-CAS time of RDRAM bank - the interval between successive COLC 4
commands).
t_PACKET Length of ROWA, ROWR, COLC, COLM or COLX packet.
4
t_RTR
Interval from COLC packet with WR command to COLC packet which
8
causes retire, and to COLM packet with bytemask.
t_OFFP
t_RDP
The interval (offset) from COLC packet with RDA command, or from
4
COLC packet with retire command (after WRA automatic precharge), or
from COLC packet with PREC command, or from COLX packet with PREX
command to the equivalent ROWR packet with PRER. The equation for
t_OFFP is given in the TPARM register in Figure 39.
Interval from last COLC packet with RD command to ROWR packet with
4
PRER.
t_RTP
Interval from last COLC packet with automatic retire command to ROWR
4
packet with PRER.
Min
-45
-711
28
20
8
8
8
7
8
6
4
4
8
4
4
4
Min
-53
-600
28
20
8
8
8
7
8
6
4
4
8
4
4
4
Max Units Figure(s)
-
t_CYCLE
64µs^b t_CYCLE
Figure 15
Figure 16
Figure 15
Figure 16
- t_CYCLE Figure 15
Figure 16
- t_CYCLE Figure 12
- t_CYCLE Figure 13
- t_CYCLE Figure 15
Figure 16
12 t_CYCLE Figure 4
Figure 39
6 t_CYCLE Figure 4
- t_CYCLE Figure 15
Figure 16
4 t_CYCLE Figure 3
- t_CYCLE Figure 17
4 t_CYCLE Figure 14
Figure 39
- t_CYCLE Figure 15
- t_CYCLE Figure 16
a. Or equivalent PREC or PREX command. See Figure 14.
b. This is a constraint imposed by the core, and is therefore in units of µs rather than t_CYCLE.
Page 54
Rev. 0.9 Jan. 2000