EMC646SP16J

4Mx16 CellularRAM

3

Preliminary

Table of Contents

Features ...................................................................................................................................................................................... 2

Options ................................................................................................................................................................................... 2

General Description .................................................................................................................................................................... 6

Functional Description ................................................................................................................................................................ 9

Power-Up Initialization ............................................................................................................................................................ 9

Bus Operating Modes ................................................................................................................................................................. 10

Asynchronous Mode ............................................................................................................................................................... 10

Page Mode READ Operation ................................................................................................................................................ 11

Burst Mode Operation ............................................................................................................................................................ 12

Mixed-Mode Operation ........................................................................................................................................................... 15

WAIT Operation ...................................................................................................................................................................... 15

LB# / UB# Operation............................................................................................................................................................... 15

Low-Power Operation......... ........................................................................................................................................................ 16

Standby Mode Operation ........................................................................................................................................................ 16

Temperature Compensated Refresh....................................................................................................................................... 16

Partial Array Refresh .............................................................................................................................................................. 16

Deep Power-Down Operation................................................................................................................................................. 16

Registers..................................................................................................................................................................................... 17

Access Using CRE ................................................................................................................................................................. 17

Software Access ..................................................................................................................................................................... 21

Bus Configuration Register...................................................................................................................................................... 22

Burst Length (BCR[2:0]) Default = Continuous Burst ......................................................................................................... 23

Burst Wrap (BCR[3]) Default = No Wrap ............................................................................................................................ 23

Drive Strength (BCR[5:4]) Default = Outputs Use Half-Drive Strength ............................................................................... 24

WAIT Configuration (BCR[8]) Default = WAIT Transitions One Clock Before Data Valid / Invalid....................................... 24

WAIT Polarity (BCR[10]) Default = WAIT Active HIGH....................................................................................................... 24

Latency Counter (BCR[13:11]) Default = Three Clock Latency .......................................................................................... 25

Initial Access Latency (BCR[14]) Default = Variable........................................................................................................... 25

Operating Mode (BCR[15]) Default = Asynchronous Operation......................................................................................... 26

Refresh Configuration Register............................................................................................................................................... 27

Partial Array Refresh (RCR[2:0]) Default = Full Array Refresh ......................................................................................... 28

Deep Power-Down (RCR[4]) Default = DPD Disabled ....................................................................................................... 28

Page Mode Operation (RCR[7]) Default = Disabled .......................................................................................................... 28

Device Identification Register.................................................................................................................................................. 28

Electrical Characteristics............................................................................................................................................................. 29

Timing Requirements................................................................................................................................................................... 31

Timing Diagrams.......................................................................................................................................................................... 35