EP4CE30F29C7N Datasheet, PDF (158/488 Pages) Altera Corporation – Cyclone IV Device Handbook, Volume 1

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Chapter 7: External Memory Interfaces in Cyclone IV Devices
Cyclone IV Devices Memory Interfaces Features
In Cyclone IV devices, the DM pins are preassigned in the device pinouts. The
Quartus II Fitter treats the DQ and DM pins in a DQS group equally for placement
purposes. The preassigned DQ and DM pins are the preferred pins to use.
Some DDR2 SDRAM and DDR SDRAM devices support error correction coding
(ECC), a method of detecting and automatically correcting errors in data
transmission. In 72-bit DDR2 or DDR SDRAM, there are eight ECC pins and 64 data
pins. Connect the DDR2 and DDR SDRAM ECC pins to a separate DQS or DQ group in
Cyclone IV devices. The memory controller needs additional logic to encode and
decode the ECC data.
Address and Control/Command Pins
The address signals and the control or command signals are typically sent at a single
data rate. You can use any of the user I/O pins on all I/O banks of Cyclone IV devices
to generate the address and control or command signals to the memory device.
1 Cyclone IV devices do not support QDR II SRAM in the burst length of two.
Memory Clock Pins
In DDR2 and DDR SDRAM memory interfaces, the memory clock signals (CK and
CK#) are used to capture the address signals and the control or command signals.
Similarly, QDR II SRAM devices use the write clocks (K and K#) to capture the
address and command signals. The CK/CK# and K/K# signals are generated to
resemble the write-data strobe using the DDIO registers in Cyclone IV devices.
1 CK/CK# pins must be placed on differential I/O pins (DIFFIO in Pin Planner) and in
the same bank or on the same side as the data pins. You can use either side of the
device for wraparound interfaces. As seen in the Pin Planner Pad View, CK0 cannot be
located in the same row and column pad group as any of the interfacing DQ pins.
f For more information about memory clock pin placement, refer to Volume 2: Device,
Pin, and Board Layout Guidelines of the External Memory Interface Handbook.
Cyclone IV Devices Memory Interfaces Features
This section discusses Cyclone IV memory interfaces, including DDR input registers,
DDR output registers, OCT, and phase-lock loops (PLLs).
DDR Input Registers
The DDR input registers are implemented with three internal logic element (LE)
registers for every DQ pin. These LE registers are located in the logic array block (LAB)
adjacent to the DDR input pin.
Cyclone IV Device Handbook,
Volume 1
May 2013 Altera Corporation