Altera ALTDLL - Manual (Page 35)

Chapter 3: Parameter Settings 3–17
ALTDQ_DQS Parameter Editor
© February 2012 Altera Corporation ALTDLL and ALTDQ_DQS Megafunctions User Guide
Table 3–10 describes the options available on the DQSn I/O page. This page allows
you to configure the DQS and DQSn I/O pins for the ALTDQ_DQS instance. These
options are used for memory interfaces that need differential or complementary
strobes.
Table 3–11 describes the options available on the Reset/Config Ports page. For more
information about reset and config ports, refer to “ALTDQ_DQS Megafunction Ports”
on page 4–33 .
Table 3–10. Options on DQS/DQSn I/O Page
Parameter Name Legal Value
Clear Box
Parameter Name Description
Use DQSn I/O — DQS_DQSN_MODE Enables access to the DQS I/O that is configured as
either differential or complementary. Altera recommends
that you use differential DQS for DDR3 interfaces to
improve signal integrity.
If the DQSn I/O is disabled, the value for the
DQS_DQSN_MODE parameter is none. When enabled,
the value may either Complementary pair or Differential
pair.
DQS and DQSn IO
Configuration
mode Differential
pair or
Complement
ary pair DQS_DQSN_MODE If you turn on the Differential pair option, the DQSn I/O
pin is configured in a differential pair along with the DQS
I/O pin. This means that the OE and OCT paths are
configured for the DQSn I/O pin, which is similar to the
DQS I/O pin. The input and output paths are shared with
the DQS I/O pin. This mode is used mainly for DDR2 and
DDR3 SDRAM, and RLDRAM II applications.
If you turn on the Complementary pair option, the DQSn
I/O pin is configured in a complementary pair along with
the DQS I/O pin. In this mode, the DQSn I/O pin is
configured similarly to the DQS I/O pin. This mode is
used mainly for QDR/QDR II applications.
Table 3–11. Options on Reset/Config Ports Page (Part 1 of 2)
Parameter Name Legal Value
Clear Box
Parameter Name Description
Reset ports
Create
'dqs_areset'
input port
— — Enables the asynchronous reset port that
asynchronously resets all registers in the DQS output or
DQS OE path.
Reset ports
Create
'dqs_sreset'
input port
— — Enables synchronous reset port that synchronously
resets all registers in the DQS output or DQS OE path.
Reset ports
Create
'input_dq_areset'
input port
— — Enables asynchronous reset port that asynchronously
resets all registers in the DQ input path.