KM416RD8AS-RBM80 datasheet(42/64 Pages) SAMSUNG

42 / 64 page

Page 39

KM416RD8AS

Direct RDRAM™

Rev. 0.9 July 1999

Target

able to frame COL packets (TFRM is a control register field

- see Figure 40). Once in ATTN state, the RDRAM will

automatically transition to the ATTNW and ATTNR states

as it receives WR and RD commands.

Once the RDRAM is in ATTN, ATTNW, or ATTNR states,

it will remain there until it is explicitly returned to the STBY

state with a RLX command. A RLX command may be given

in an ROWR, COLC , or COLX packet (see the left side of

Figure 46). It is usually given after all banks of the RDRAM

have been precharged; if other banks are still activated, then

the RLX command would probably not be given.

If a broadcast ROWA packet or ROWR packet (with the

ATTN command) is received, the RDRAM’s power state

doesn’t change. If a broadcast ROWR packet with RLXR

command is received, the RDRAM goes to STBY.

Figure 47 shows the NAP entry sequence (left). NAP state is

entered by sending a NAPR command in a ROW packet. A

time tASN is required to enter NAP state (this specification is

provided for power calculation purposes). The clock on

CTM/CFM must remain stable for a time tCD after the

NAPR command.

The RDRAM may be in ATTN or STBY state when the

NAPR command is issued. When NAP state is exited, the

RDRAM will return to the original starting state (ATTN or

STBY). If it is in ATTN state and a RLXR command is

specified with NAPR, then the RDRAM will return to STBY

state when NAP is exited.

Figure 47 also shows the PDN entry sequence (right). PDN

state is entered by sending a PDNR command in a ROW

packet. A time tASP is required to enter PDN state (this spec-

ification is provided for power calculation purposes). The

clock on CTM/CFM must remain stable for a time tCD after

the PDNR command.

The RDRAM may be in ATTN or STBY state when the

PDNR command is issued. When PDN state is exited, the

RDRAM will return to the original starting state (ATTN or

STBY). If it is in ATTN state and a RLXR command is

specified with PDNR, then the RDRAM will return to STBY

state when PDN is exited. The current- and slew-rate-control

levels are re-established.

The RDRAM’s write buffer must be retired with the appro-

priate COP command before NAP or PDN are entered. Also,

all the RDRAM’s banks must be precharged before NAP or

PDN are entered. The exception to this is if NAP is entered

with the NSR bit of the INIT register cleared (disabling self-

refresh in NAP). The commands for relaxing, retiring, and

precharging may be given to the RDRAM as late as the

ROPa0, COPa0, and XOPa0 packets in Figure 47. No broad-

cast packets nor packets directed to the RDRAM entering

Nap or PDN may overlay the quiet window. This window

extends for a time tNPQ after the packet with the NAPR or

PDNR command.

Figure 48 shows the NAP and PDN exit sequences. These

sequences are virtually identical; the minor differences will

be highlighted in the following description.

Before NAP or PDN exit, the CTM/CFM clock must be

stable for a time tCE. Then, on a falling and rising edge of

SCK, if there is a “01” on the CMD input, NAP or PDN state

will be exited. Also, on the falling SCK edge the SIO0 input

must be at a 0 for NAP exit and 1 for PDN exit.

If the PSX bit of the INIT register is 0, then a device

PDEV5..0 is specified for NAP or PDN exit on the DQA5..0

pins. This value is driven on the rising SCK edge 0.5 or 1.5

SCK cycles after the original falling edge, depending upon

the value of the DQS bit of the NAPX register. If the PSX bit

of the INIT register is 1, then the RDRAM ignores the

Figure 45: Power State Transition Diagram

automatic

ATTNR

ATTNW

ATTN

STBY

SETR/CLRR

NAP-A

NAPR • RLXR

Notation:

SETR/CLRR - SETR/CLRR Reset sequence in SRQ packets

tNLIMIT

NAP

NAP-S

PDEV.CMD• SIO0

NAPR • RLXR

PDEV.CMD• SIO0

PDN-A

PDNR • RLXR

PDN

PDN-S

PDEV.CMD•SIO0

PDNR • RLXR

PDEV.CMD•SIO0

PDNR - PDNR command in ROWR packet

NAPR - NAPR command in ROWR packet

RLXR - RLX command in ROWR packet

RLX - RLX command in ROWR,COLC,COLX packets

SIO0 - SIO0 input value

PDEV.CMD - (PDEV=DEVID)•(CMD=01)

ATTN - ROWA packet (non-broadcast) or ROWR packet

(non-broadcast) with ATTN command

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