Altera ALTDLL - Manual (Page 108)

A–7
Clear Box Generator Options
© February 2012 Altera Corporation ALTDLL and ALTDQ_DQS Megafunctions User Guide
USE_DQS_DELAY_CHAIN_
PHASECTRLIN
OptionalO FALSE FALSE, TRUE This parameter is the signal used to
choose the phase applied to the
dqsbusout output when
<use_phasectrlin> is set to TRUE ;
otherwise, the phase setting is
determined by the <phase_setting>
parameter. Only feed this port by the
dqsinputphasesetting output
port of the DQS config. You must
connect this port if <use_phasectrlin>
is set to
TRUE ; otherwise, this port is
optional and defaults to GND . This
input must match the polarity of its
source and cannot be inverted.
DQS_DELAY_CHAIN_PHASE_
SETTING
Optional 0 0, 1, 2, 3, 4 This parameter is a delay chain setting.
If <use_phasectrlin> is set to
FALSE ,
this parameter sets the number of DQS
delay buffers that the
dqsin signal
should travel through to the
dqsbusout port; otherwise, you can
ignore this setting. When it is set to 0 ,
the dqsbusout signal bypasses the
DQS delay chain. When it is set to 1 , 2 ,
3 , or 4 , the dqsbusout signal goes
through 1, 2, 3, or 4 delay buffers,
respectively, that are controlled by
delayctrlin[5..0] . The
phase-shift implemented is determined
by the ratio of the DQS delay buffers to
DLL delay buffers: phase_shift =
phase_setting/DLL delay_chain_length
* 360
DELAY_BUFFER_MODE Optional LOW LOW, HIGH This parameter determines whether the
variable delay buffers are working in
low-frequency mode or high-frequency
mode.
DQS_PHASE_SHIFT Optional 0 0..36,000 This parameter indicates the phase
shift between the delayed DQS signal
and the input DQS signal in units of
hundreds of degrees (for example, a
90° phase shift is represented as
9,000). This parameter is applicable
only for static timing analysis because
the phase shift through the
delayctrlin[5..0] ,
phasectrlin[2..0] , and
offsetctrlin[5..0] ports
cannot be determined.
DQS_OFFSETCTRL_ENABLE Optional FALSE FALSE, TRUE This parameter describes whether the
offsetctrlin[5..0] inputs are
used.
Table A–3. Megafunction Parameters to Configure DQS Input Path (Part 2 of 4)
Parameter Name
Optional/
Required Default Legal Values Description