Altera ALTDLL Manual de usuario descargar pdf (Pagina 108)

A–7

Clear Box Generator Options

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

1 2 ... 103 104 105 106 107 108 109 110 111 112 113 ... 116 117

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Altera ALTDLL Manual de usuario Pagina 108

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