KM416RD8AS-RBM80 datasheet(16/64 Pages) SAMSUNG

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Page 13

KM416RD8AS

Direct RDRAM™

Target

Rev. 0.9 July 1999

ROW-to-ROW Interaction - contin-

ued

Cases RR13 through RR16 summarize the combinations of

two successive PRER commands. In case RR13 there is no

restriction since two devices are addressed. In RR14, tPP

applies, since the same device is addressed. In RR15 and

RR16, the same bank or an adjacent bank may be given

repeated PRER commands with only the tPP restriction.

Two adjacent banks can’t be activate simultaneously. A

precharge command to one bank will thus affect the state of

the adjacent banks (and sense amps). If bank Ba is activate

and a PRER is directed to Ba, then bank Ba will be

precharged along with sense amps Ba-1/Ba and Ba/Ba+1. If

bank Ba+1 is activate and a PRER is directed to Ba, then

bank Ba+1 will be precharged along with sense amps

Ba/Ba+1 and Ba+1/Ba+2. If bank Ba-1 is activate and a

PRER is directed to Ba, then bank Ba-1 will be precharged

along with sense amps Ba/Ba-1 and Ba-1/Ba-2.

A ROW packet may contain commands other than ACT or

PRER. The REFA and REFP commands are equivalent to

ACT and PRER for interaction analysis purposes. The inter-

action rules of the NAPR, NAPRC, PDNR, RLXR, ATTN,

TCAL, and TCEN commands are discussed in later sections

(see Table 7 for cross-ref).

ROW-to-COL Packet Interaction

Figure 7 shows two packets on the ROW and COL pins.

They must be separated by an interval tRCDELAY which

depends upon the packet contents. Table 11 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 15 and

Figure 16 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 inter-

action 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 inter-

action (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 14.

Figure 7: ROW-to-COL Packet Interaction- Timing

CTM/CFM

DQA7..0

DQB7..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 11: ROW-to-COL Packet Interaction - Rules

Case #

ROPa

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 15

RC6

PRER

NOCOP,RD,retire

/= Da

xxxx

x..x

RC7

PRER

NOCOP

== Da

xxxx

x..x

RC8

PRER

RD,retire

== Da

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

x..x

RC9

PRER

RD,retire

== Da

== {Ba+1,Ba-1}

x..x

Illegal

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