EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 220

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

External Memory Interfaces in Cyclone III Devices
Figure 9–3. Cyclone III DQ and DQS pins
Notes to
(1)
(2)
(3)
9–6
Cyclone III Device Handbook, Volume 1
Each
DQ
DM
DQ groups on the bottom sides of EP3C10, EP3C16, and EP3C25 (of the 144-pin EQFP package) do not support
pin.
groups on the left and right sides of EP3C16, EP3C25, and EP3C40 (of the 240-pin PQFP package) do not support
pin.
Figure
DQ
group consists of a
9–3:
DQ Pins
Data and Data Clock/Strobe Pins
Cyclone III 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 III 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 QDRII SRAM). Connect the bidirectional DQ data signals to
the same Cyclone III 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.
In Cyclone III devices, DQS is used only during write mode in DDR2 and
DDR SDRAM interfaces. Cyclone III devices ignore DQS as the read-data
strobe because the physical layer (PHY) internally generates the read
capture clock for read mode. However, you must connect the DQS pin to
the DQS signal in DDR2 and DDR SDRAM interfaces, or to the CQ signal
in QDRII SRAM interfaces.
1
DQS
pin, a
Cyclone III does not support differential strobe pins, which is an
optional feature in DDR2 SDRAM devices.
Note
DM
pin and
(1), (2),
DQS Pin
DQ
(3)
pins.
DQ Pins
Altera Corporation-Preliminary
March 2007
DM Pin
DM