PD488588FF datasheet(18/79 Pages) ELPIDA

18 / 79 page

Data Sheet

E0251N20 (Ver. 2.0)

µµµµPD488588FF-C80-40

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

CTM/CFM

DQA8..0

DQB8..0

COL4

..COL0

ROW2

..ROW0

T12

T13

T10

T14

T11

T15 T16

T17 T18 T19

Transaction a: ROPa

Transaction b: COPb

a0 = {Da,Ba,Ra}

b1= {Db,Bb,Cb1}

tRCDELAY

ROPa a0

COPb b1

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.

Table 7-1 ROW-to-COL Packet Interaction - Rules

Case # ROPa Da

COPb

Cb1

tRCDELAY

Example

RC1

ACT

NOCOP, RD, retire

/= Da

xxxx

x..x

RC2

ACT

NOCOP

== Da

xxxx

x..x

RC3

ACT

RD, retire

== Da

/= {Ba, Ba+1, Ba-1}

x..x

RC4

ACT

RD, retire

== Da

== {Ba+1, Ba-1}

x..x

Illegal

RC5

ACT

RD, retire

== Da

== {Ba}

x..x

tRCD

Figure 13-1

RC6

PRER Da

NOCOP, RD, retire

/= Da

xxxx

x..x

RC7

PRER Da

NOCOP

== Da

xxxx

x..x

RC8

PRER Da

RD, retire

== Da

/= {Ba, Ba+1, Ba-1}

x..x

RC9

PRER Da

RD, retire

== Da

== {Ba+1, Ba-1}

x..x

Illegal

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