Cyclone Iv Devices Memory Interfaces Pin Support; Data And Data Clock/Strobe Pins - Altera Cyclone IV Device Handbook

7–2
Figure 7–1
in Cyclone IV devices.
Figure 7–1. Cyclone IV Devices External Memory Data Path
OE
IOE
Register
Register
System Clock
PLL
-90° Shifted Clock
Note to Figure 7–1:
(1) All clocks shown here are global clocks.
f
For more information about implementing complete external memory interfaces, refer
to the

Cyclone IV Devices Memory Interfaces Pin Support

Cyclone IV devices use data (DQ), data strobe (DQS), clock, command, and address
pins to interface with external memory. Some memory interfaces use the data mask
(DM) or byte write select (BWS#) pins to enable data masking. This section describes
how Cyclone IV devices support all these different pins.
f
For more information about pin utilization, refer to
Layout Guidelines

Data and Data Clock/Strobe Pins

Cyclone IV data pins for external memory interfaces are called D for write data, Q for
read data, or DQ for shared read and write data pins. The read-data strobes or read
clocks are called DQS pins. Cyclone IV devices support both bidirectional data strobes
and unidirectional read clocks. Depending on the external memory standard, the DQ
and DQS are bidirectional signals (in DDR2 and DDR SDRAM) or unidirectional
signals (in QDR II SRAM). Connect the bidirectional DQ data signals to the same
Cyclone IV devices DQ pins. For unidirectional D or Q signals, connect the read-data
signals to a group of DQ pins and the write-data signals to a different group of DQ pins.
1
In QDR II SRAM, the Q read-data group must be placed at a different V
location from the D write-data group, command, or address pins.
Cyclone IV Device Handbook,
Volume 1
shows the block diagram of a typical external memory interface data path
DQS/CQ/CQn
OE
IOE
V CC
IOE
Register
GND IOE
Register
Capture Clock
External Memory Interface
of the External Memory Interface Handbook.
Chapter 7: External Memory Interfaces in Cyclone IV Devices
Cyclone IV Devices Memory Interfaces Pin Support
(1)
DQ
IOE
Register
IOE
Register
IOE
DataA
Register
DataB
IOE
Register
Handbook.
Volume 2: Device, Pin, and Board
LE
Register
LE LE
Register Register
bank
REF
March 2016 Altera Corporation