Intel PXA255 User Manual

Page 6

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Intel® PXA255 Processor Developer’s Manual

Contents

6.2.1

SDRAM Interface Overview.................................................................................. 6-2

6.2.2

Static Memory Interface / Variable Latency I/O Interface .....................................6-3

6.2.3

16-Bit PC Card / Compact Flash Interface ...........................................................6-4

6.3

Memory System Examples ................................................................................................6-4

6.4

Memory Accesses .............................................................................................................6-7
6.4.1

Reads and Writes .................................................................................................6-8

6.4.2

Aborts and Nonexistent Memory ..........................................................................6-8

6.5

Synchronous DRAM Memory Interface .............................................................................6-8
6.5.1

SDRAM MDCNFG Register (MDCNFG................................................................6-8

6.5.2

SDRAM Mode Register Set Configuration Register (MDMRS) ..........................6-12

6.5.3

SDRAM MDREFR Register (MDREFR) .............................................................6-14

6.5.4

Fixed-Delay or Return-Clock Data Latching .......................................................6-17

6.5.5

SDRAM Memory Options ...................................................................................6-18

6.5.6

SDRAM Command Overview .............................................................................6-27

6.5.7

SDRAM Waveforms............................................................................................6-28

6.6

Synchronous Static Memory Interface.............................................................................6-32
6.6.1

Synchronous Static Memory Configuration Register (SXCNFG)........................6-32

6.6.2

Synchronous Static Memory Mode Register Set Configuration
Register (SXMRS) ..............................................................................................6-37

6.6.3

Synchronous Static Memory Timing Diagrams...................................................6-38

6.6.4

Non-SDRAM Timing SXMEM Operation ............................................................6-39

6.7

Asynchronous Static Memory ..........................................................................................6-42
6.7.1

Static Memory Interface......................................................................................6-42

6.7.2

Asynchronous Static Memory Control Registers (MSCx) ...................................6-44

6.7.3

ROM Interface ....................................................................................................6-48

6.7.4

SRAM Interface Overview ..................................................................................6-51

6.7.5

Variable Latency I/O (VLIO) Interface Overview.................................................6-53

6.7.6

FLASH Memory Interface ...................................................................................6-56

6.8

16-Bit PC Card/Compact Flash Interface ........................................................................6-58
6.8.1

Expansion Memory Timing Configuration Register ............................................6-58

6.8.2

Expansion Memory Configuration Register (MECR) ..........................................6-61

6.8.3

16-Bit PC Card Overview....................................................................................6-62

6.8.4

External Logic for 16-Bit PC Card Implementation .............................................6-64

6.8.5

Expansion Card Interface Timing Diagrams and Parameters ............................6-67

6.9

Companion Chip Interface ...............................................................................................6-68
6.9.1

Alternate Bus Master Mode ................................................................................6-70

6.10

Options and Settings for Boot Memory............................................................................6-72
6.10.1 Alternate Booting ................................................................................................6-72
6.10.2 Boot Time Defaults .............................................................................................6-72
6.10.3 Memory Interface Reset and Initialization...........................................................6-76

6.11

Hardware, Watchdog, or Sleep Reset Operation ............................................................6-77

6.12

GPIO Reset Procedure....................................................................................................6-79

6.13

Memory Controller Register Summary ............................................................................6-79

7

LCD Controller..............................................................................................................................7-1

7.1

Overview............................................................................................................................7-1
7.1.1

Features................................................................................................................ 7-2

7.1.2

Pin Descriptions....................................................................................................7-4

7.2

LCD Controller Operation ..................................................................................................7-4
7.2.1

Enabling the Controller .........................................................................................7-4

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