EM636165TS-6I/6IG 参数 Datasheet PDF下载

EtronTech

Commands

1

1M x 16 SDRAM

EM636165-XXI

BankPrecharge command

(RAS# = "L", CAS# = "H", WE# = "L", A11 =

“V”,

A10 = "L", A0-A9 = Don't care)

The BankPrecharge command precharges the bank disignated by A11 signal. The precharged

bank is switched from the active state to the idle state. This command can be asserted anytime after

t

RAS

(min.) is satisfied from the BankActivate command in the desired bank. The maximum time any

bank can be active is specified by t

RAS

(max.). Therefore, the precharge function must be performed

in any active bank within t

RAS

(max.). At the end of precharge, the precharged bank is still in the idle

state and is ready to be activated again.

PrechargeAll command

(RAS# = "L", CAS# = "H", WE# = "L", A11 = Don't care, A10 = "H", A0-A9 = Don't care)

The PrechargeAll command precharges both banks simultaneously and can be issued even if

both banks are not in the active state. Both banks are then switched to the idle state.

Read command

(RAS# = "H", CAS# = "L", WE# = "H", A11=

“V”,

A9 = "L", A0-A7 = Column Address)

The Read command is used to read a burst of data on consecutive clock cycles from an active

row in an active bank. The bank must be active for at least t

RCD

(min.) before the Read command is

issued. During read bursts, the valid data-out element from the starting column address will be

available following the CAS# latency after the issue of the Read command. Each subsequent data-

out element will be valid by the next positive clock edge (refer to the following figure). The DQs go

into high-impedance at the end of the burst unless other command is initiated. The burst length,

burst sequence, and CAS# latency are determined by the mode register, which is already

programmed. A full-page burst will continue until terminated (at the end of the page it will wrap to

column 0 and continue).

T0

T1

T2

T3

T4

T5

T6

T7

T8

2

3

CLK

COM MAND

READ A

NOP

NOP

NOP

NOP

NOP

NOP

NOP

NOP

CAS# latency=1

tCK1, DQ's

CAS# latency=2

tCK2, DQ's

CAS# latency=3

tCK3, DQ's

DOUT A0

DOUT A1

DOUT A2

DOUT A3

DOUT A0

DOUT A1

DOUT A2

DOUT A3

DOUT A0

DOUT A1

DOUT A2

DOUT A3

Burst Read Operation

(Burst Length = 4, CAS# Latency = 1, 2, 3)

Preliminary

6

Rev. 1.1

Apr. 2005