PD488588 Datasheet, PDF (18/79 Pages) Elpida Memory – 288M bits Direct Rambus DRAM

µPD488588
7. ROW-to-COL Packet Interaction
Figure 7-1 shows two packets on the ROW and COL pins. They must be separated by an interval tRCDELAY which
depends upon the packet contents.
Figure 7-1 ROW-to-COL Packet Interaction- Timing
T₀ T₁ T₂ T₃ T₄ T₅ T₆ T₇ T₈ T₉ T₁₀ T₁₁T₁₂T₁₃ T₁₄ T₁₅ T₁₆T₁₇ T₁₈ T₁₉ T
CTM/CFM
ROW2
ROPa a0
..ROW0
t_RCDELAY
COL4
..COL0
COPb b1
DQA8..0
DQB8..0
Transaction a: ROPa a0 = {Da,Ba,Ra}
Transaction b: COPb b1= {Db,Bb,Cb1}
Table 7-1 summarizes the tRCDELAY values for all possible cases. Note that if the COL packet is earlier than the
ROW packet, it is considered a COL-to-ROW packet interaction.
Cases RC1 through RC5 summarize the rules when the ROW packet has an ACT command. Figure 13-1 and
Figure 14-1 show examples of RC5 - an activation followed by a read or write. RC4 is an illegal situation, since a
read or write of a precharged banks is being attempted (remember that for a bank to be activated, adjacent banks
must be precharged). In cases RC1, RC2, and RC3, there is no interaction of the ROW and COL packets.
Cases RC6 through RC8 summarize the rules when the ROW packet has a PRER command. There is either no
interaction (RC6 through RC9) or an illegal situation with a read or write of a precharged bank (RC9).
The COL pins can also schedule a precharge operation with a RDA, WRA, or PREC command in a COLC packet or
a PREX command in a COLX packet. The constraints of these precharge operations may be converted to equivalent
PRER command constraints using the rules summarized in Figure 12-2.
Case # ROPa Da Ba
RC1 ACT Da Ba
RC2 ACT Da Ba
RC3 ACT Da Ba
RC4 ACT Da Ba
RC5 ACT Da Ba
RC6 PRER Da Ba
RC7 PRER Da Ba
RC8 PRER Da Ba
RC9 PRER Da Ba
Table 7-1 ROW-to-COL Packet Interaction - Rules
Ra COPb
Db
Bb
Cb1
Ra NOCOP, RD, retire /= Da xxxx
x..x
Ra NOCOP
== Da xxxx
x..x
Ra RD, retire
== Da /= {Ba, Ba+1, Ba-1} x..x
Ra RD, retire
== Da == {Ba+1, Ba-1}
x..x
Ra RD, retire
== Da == {Ba}
x..x
Ra NOCOP, RD, retire /= Da xxxx
x..x
Ra NOCOP
== Da xxxx
x..x
Ra RD, retire
== Da /= {Ba, Ba+1, Ba-1} x..x
Ra RD, retire
== Da == {Ba+1, Ba-1}
x..x
tRCDELAY Example
0
0
0
Illegal
tRCD
Figure 13-1
0
0
0
Illegal
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Data Sheet E0039N30 (Ver. 3.0)