Xilinx V2.1 manual Delay block parameters dialog box

Xilinx Blocks

Xilinx LogiCORE

The block always uses the Xilinx LogiCORE: Binary Counter V5.0.

The Core datasheet can be found on your local disk at:

%XILINX%\coregen\ip\xilinx\eip1\com\xilinx\ip\baseblox_v5_0\do c\binary_counter.pdf

Delay

The Xilinx Delay block is a delay line (also called a shift register) of configurable length, allowing you to add latency to your design. Data presented at the input will appear at the output after a user specified number of sample periods.

The Delay block differs from the Register in that the Register allows only latency of 1, and contains an Initial Value parameter. The Delay block supports a user specified latency, but no initial value, other than zeroes.

Block Parameters Dialog Box

The block parameters dialog box can be invoked by double-clicking the icon in your Simulink model.

Figure 3-9: Delay block parameters dialog box

Parameters specific to this block are:

∙Initialize with Zeros: The block’s internal registers are set to zero if this option is selected, otherwise the output will be NaN (Not a Number) until the registers are flushed. For example, if the Delay block has a latency of 5 and this option is selected, the first five output values will be zeros. If this option is not selected, the first five output values will be NaN.

∙Latency: You may set the amount of latency in the Latency field.

Other parameters used by this block are explained in the Common Parameters section of the previous chapter.

The Delay block does not use a Xilinx LogiCORE, but is efficiently mapped to utilize the SRL16 feature of Xilinx devices.

Basic Elements 35