IMC020FLSA 데이터 시트보기 (PDF) - Intel

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IMC020FLSA

SERIES 2 FLASH MEMORY CARDS

Intel 

SERIES 2 FLASH MEMORY CARDS

If the READY-BUSY MASK REGISTER bits are set

to ones (masked condition) the RDY BSY output

and the CARD STATUS REGISTER RDY BSY bit

will reflect a READY condition regardless of the

state of the corresponding devices The READY-

BUSY MASK REGISTER does not affect the

READY-BUSY STATUS REGISTER allowing soft-

ware polling to determine operation status

Unmasked is the default condition for the bits in this

register On memory cards with fewer than 20 devic-

es unused device mask bits appear as masked

READY-BUSY MODE REGISTER

(INTEL)

The READY-BUSY MODE REGISTER (Attribute

Memory Plane Address 4140H Figure 12) provides

the selection of two types of system interfacing for

the busy-to-ready transition of the card’s

RDY BSY pin

1 The standard PCMCIA READY-BUSY MODE in

which the card’s RDY BSY signal generates a

low-to-high transition (from busy to ready) only

after all busy devices (not including masked

devices) have completed their data-write or block-

erase operations This may result in a long inter-

rupt latency

2 A High-Performance mode that generates a low-

to-high (from busy-to-ready) transition after each

device becomes ready This provides the host

system with immediate notification that a specific

device’s operation has completed and that de-

vice may now be used This is particularly useful

in a file management application where a block

pair containing only deleted files is being erased

to free up space so new file data may be written

Enabling the HIGH-PERFORMANCE READY-BUSY

MODE requires a three step sequence

1 Set all bits in the READY BUSY MASK REGIS-

TER This prevents ready devices from triggering

an unwanted interrupt when step 3 is performed

2 Write 01H to the READY-BUSY MODE REGIS-

TER This sets the MODE bit

3 Write 01H to the READY-BUSY MODE REGIS-

TER This clears the RACK bit

The MODE and RACK bits must be written in the

prescribed sequence not simultaneously The

card’s circuitry is designed purposely in this manner

to prevent an initial unwanted busy-to-ready tran-

sition Note that in Step 2 writing to the RACK bit is

a Don’t Care

When the High-Performance Mode is enabled spe-

cific READY-BUSY MASK bits must be cleared after

an operation is initiated on the respective devices

After each device becomes ready the RDY BSY

pin makes a low-to-high transition To catch the next

device’s completion of an operation the RACK bit

must be cleared by writing ‘‘01H’’ to the Ready Busy

Mode Register

ADDRESS

4140H

BIT 7

READY-BUSY MODE REGISTER

(Read Write Register)

BIT 6

BIT 5

BIT 4

BIT 3

RESERVED FOR FUTURE USE

BIT 2

BIT 1

RACK

BIT 0

MODE

MODE e READY-BUSY MODE

0 e PCMCIA MODE

1 e HIGH PERFORMANCE

RACK e READY ACKNOWLEDGE CLEAR TO

SET UP RDY BSY PIN THEN CLEAR AFTER

EACH DEVICE BECOMES READY TO ACKNOWL-

EDGE TRANSITION

Figure 12 High Performance Ready-Busy Mode REGISTER (Intel)

Used to Trigger a Ready Interrupt for Each Device

15

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