Contents
clkena signals ..................................................................................................................................
Board Layout ........................................................................................................................................
VCCA & GNDA .............................................................................................................................
VCCD & GND .................................................................................................................................
Conclusion ............................................................................................................................................
7–29
7–30
7–31
7–33
7–33
Section III. Memory
Revision History .................................................................................................................................... 7–1
Chapter 8. Cyclone II Memory Blocks
Introduction ............................................................................................................................................ 8–1
Overview ................................................................................................................................................. 8–1
Control Signals .................................................................................................................................. 8–3
Parity Bit Support ............................................................................................................................. 8–4
Byte Enable Support ........................................................................................................................ 8–4
Packed Mode Support ..................................................................................................................... 8–6
Address Clock Enable ...................................................................................................................... 8–6
Memory Modes ...................................................................................................................................... 8–8
Single-Port Mode .............................................................................................................................. 8–9
Simple Dual-Port Mode ................................................................................................................. 8–10
True Dual-Port Mode ..................................................................................................................... 8–12
Shift Register Mode ........................................................................................................................ 8–14
ROM Mode ...................................................................................................................................... 8–16
FIFO Buffer Mode ........................................................................................................................... 8–16
Clock Modes ......................................................................................................................................... 8–16
Independent Clock Mode .............................................................................................................. 8–17
Input/Output Clock Mode ........................................................................................................... 8–19
Read/Write Clock Mode ............................................................................................................... 8–22
Single-Clock Mode ......................................................................................................................... 8–24
Power-Up Conditions & Memory Initialization ........................................................................ 8–27
Read-During- Write Operation at the Same Address .................................................................... 8–28
Same-Port Read-During-Write Mode .......................................................................................... 8–28
Mixed-Port Read-During-Write Mode ........................................................................................ 8–29
Conclusion ............................................................................................................................................ 8–30
Referenced Documents ....................................................................................................................... 8–30
Chapter 9. External Memory Interfaces
Introduction ............................................................................................................................................ 9–1
External Memory Interface Standards ................................................................................................ 9–2
DDR & DDR2 SDRAM .................................................................................................................... 9–2
QDRII SRAM ..................................................................................................................................... 9–5
Cyclone II DDR Memory Support Overview .................................................................................... 9–9
Data & Data Strobe Pins ................................................................................................................ 9–10
Clock, Command & Address Pins ............................................................................................... 9–14
Parity, DM & ECC Pins ................................................................................................................. 9–14
vi
Cyclone II Device Handbook, Volume 1
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