ep2c35 Altera Corporation, ep2c35 Datasheet - Page 59

• Manufacturer Part Number: ep2c35
• Description: Cyclone Ii Device Family Data Sheet
• Manufacturer: Altera Corporation

Altera Corporation
February 2007
Notes to
(1)
(2)
(3)
(4)
(5)
(6)
EP2C35
EP2C50
EP2C70
Table 2–15. Cyclone II DQS & DQ Bus Mode Support (Part 2 of 2)
Device
Numbers are preliminary.
EP2C5 and EP2C8 devices in the 144-pin TQFP package do not have any DQ pin groups in I/O bank 1.
Because of available clock resources, only a total of 6 DQ/DQS groups can be implemented.
Because of available clock resources, only a total of 14 DQ/DQS groups can be implemented.
The ×9 DQS/DQ groups are also used as ×8 DQS/DQ groups. The ×18 DQS/DQ groups are also used as ×16
DQS/DQ groups.
For QDRI implementation, if you connect the D ports (write data) to the Cyclone II DQ pins, the total available ×9
DQS /DQ and ×18 DQS/DQ groups are half of that shown in
Table
2–15:
484-pin FineLine BGA
672-pin FineLine BGA
484-pin FineLine BGA
672-pin FineLine BGA
672-pin FineLine BGA
896-pin FineLine BGA
Package
You can use any of the DQ pins for the parity pins in Cyclone II devices.
The Cyclone II device family supports parity in the ×8/×9, and ×16/×18
mode. There is one parity bit available per eight bits of data pins.
The data mask, DM, pins are required when writing to DDR SDRAM and
DDR2 SDRAM devices. A low signal on the DM pin indicates that the
write is valid. If the DM signal is high, the memory masks the DQ signals.
In Cyclone II devices, the DM pins are assigned and are the preferred
pins. Each group of DQS and DQ signals requires a DM pin.
When using the Cyclone II I/O banks to interface with the DDR memory,
at least one PLL with two clock outputs is needed to generate the system
and write clock. The system clock is used to clock the DQS write signals,
commands, and addresses. The write clock is shifted by –90° from the
system clock and is used to clock the DQ signals during writes.
Figure 2–27
the dedicated circuitry to the logic array.
Number of ×8
illustrates DDR SDRAM interfacing from the I/O through
Groups
16
20
16
20
20
20
(4)
(4)
(4)
(4)
(4)
(4)
Groups (5),
Number of ×9
Table
8
8
8
8
8
8
2–15.
Cyclone II Device Handbook, Volume 1
(6)
Note (1)
Number of ×16
Groups
8
8
8
8
8
8
Cyclone II Architecture
Number of ×18
Groups (5),
8
8
8
8
8
8
2–47
(6)