PD488588FF Datasheet, PDF (66/79 Pages) Elpida Memory – 288M bits Direct Rambus DRAM for High Performance Solution

µPD488588FF-C80-40
36. Timing Parameters
Timing Parameters Summary
Para- Description
-C80
Units Figures
meter
-40
MIN. MAX.
tRC
Row Cycle time of RDRAM banks - the interval between ROWA packets 28
— tCYCLE Figure13-1
with ACT commands to the same bank.
Figure14-1
tRAS ^{RAS-asserted time of RDRAM bank - the interval between ROWA packet}
20
Note 2 tCYCLE Figure13-1
with ACT command and next ROWR packet with PRER ^{Note 1} command to the
64µs
Figure14-1
same bank.
tRP ^{Row Precharge time of RDRAM banks - the interval between ROWR packet 8}
with PRER ^{Note 1} command and next ROWA packet with ACT command to the
same bank.
— tCYCLE Figure13-1
Figure14-1
tPP ^{Precharge-to-precharge time of RDRAM device - the interval between}
8
— tCYCLE Figure10-3
successive ROWR packets with PRER ^Note1 commands to any banks of
the same device.
tRR ^{RAS-to-RAS time of RDRAM device - the interval between successive}
8
ROWA packets with ACT commands to any banks of the same device.
— tCYCLE Figure12-1
tRCD ^{RAS-to-CAS Delay - the interval from ROWA packet with ACT}
7
— tCYCLE Figure13-1
command to COLC packet with RD or WR command. Note - the RAS-
Figure14-1
to-CAS delay seen by the RDRAM core (tRCD-C) is equal to tRCD-C = 1 +
tRCD because of differences in the row and column paths through the
RDRAM interface.
tCAC ^{CAS Access delay - the interval from RD command to Q read data. The 8}
equation for tCAC is given in the TPARM register in Figure 22-1(5/7).
tCWD ^{CAS Write Delay - interval from WR command to D write data.}
6
tCC ^{CAS-to-CAS time of RDRAM bank - the interval between successive}
4
COLC commands.
tPACKET ^{Length of ROWA, ROWR, COLC, COLM or COLX packet.}
4
tRTR ^{Interval from COLC packet with WR command to COLC packet which}
8
causes retire, and to COLM packet with bytemask.
12 tCYCLE Figure4-1
6 tCYCLE Figure4-1
— tCYCLE Figure13-1
Figure14-1
4 tCYCLE Figure2-1
— tCYCLE Figure15-1
tOFFP ^{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 tOFFP is given in the TPARM register in Figure 22-1(5/7).
tRDP ^{Interval from last COLC packet with RD command to ROWR packet}
4
with PRER.
tRTP ^{Interval from last COLC packet with automatic retire command to}
4
ROWR packet with PRER.
4 tCYCLE Figure14-2
— tCYCLE Figure13-1
— tCYCLE Figure14-1
Notes 1. Or equivalent PREC or PREX command. See Figure 12-2.
2. This is a constraint imposed by the core, and is therefore in units of ms rather than tCYCLE.
66
Data Sheet E0251N20 (Ver. 2.0)