EMC326SP16AJS-90LL datasheet(17/64 Pages) EMLSI

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EMC326SP16AJ

2Mx16 CellularRAM

Preliminary

Registers

Two user-accessible configuration registers define the device operation. The bus configuration register (BCR) defines how the Cellu-

larRAM interacts with the system memory bus and is nearly identical to its counterpart on burst mode Flash devices. The refresh

configuration register (RCR) is used to control how refresh is performed on the DRAM array. These registers are automatically loaded

with default settings during power-up, and can be updated any time the devices are operating in a standby state. A DIDR provides

information on the device manufacturer, CellularRAM generation, and the specific device configuration. The DIDR is read-only.

Access Using CRE

The registers can be accessed using either a synchronous or an asynchronous operation when the control register enable (CRE) input

is HIGH. (See Figure 10 through 13) When CRE is LOW, a READ or WRITE operation will access the memory array. The configuration

register values are written via addresses A[20:0]. In an asynchronous WRITE, the values are latched into the configuration register on

the rising edge of ADV#, CE#, or WE#, whichever occurs first; LB# and UB# are “Don’t Care”. The BCR is accessed when A[19:18]

are 10b; the RCR is accessed when A[19:18] are 00b. The DIDR is read when A[19:18] are 01b. For reads, address inputs other than

A[19:18] are “Don’t Care”, and register bits 15:0 are output on DQ[15:0]. Immediately after performing a configuration register READ or

WRITE operation, reading the memory array is highly recommended.

Figure 10: Configuration Register WRITE, Asynchronous Mode, Followed by READ ARRAY Operation

Note: 1. A[19:18] = 00b to load RCR, and 10b to load BCR.

Don’t Care

CE#

A[20:0]

OE#

WE#

LB#/UB#

DQ[15:0]

OPCODE

Address

A[19:18]1

(except A[19:18])

CRE

Initiate control register access

Data Valid

Write address bus value

tAVS

tCPH

Address

Select control register

tAVH

tAVS

tAVH

tCW

to control register

tWP

ADV#

tVP

EMC326SP16AJS-90LL Datasheet(PDF) 17 Page - Emerging Memory & Logic Solutions Inc

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