Setting the Number of Capture Windows

Setting the Number of Capture Windows - 2021.2 English

Vivado Design Suite User Guide: Programming and Debugging

Document ID

UG908

Release Date

2021-10-22

Version

2021.2 English

The ILA capture data buffer can be subdivided into one or more capture windows. The depth each window is a power of 2 number of samples from 1 to (((buffer size) / (number of windows)) - 1). For example, if the ILA data buffer is 1024 samples deep and is segmented into four capture windows, then each window can be up to 256 samples deep. Each capture window has its own trigger mark corresponding to the trigger event that caused the capture window to fill.

Note: An ILA buffer size equal to the number of capture windows is not supported.

Tip: Click Stop Trigger before the entire ILA data capture buffer is full to upload and display all capture windows that have been filled. For example, if the ILA data buffer is segmented into four windows, and three of them have filled with data, click Stop Trigger to halt the ILA core and upload and display the three filled capture windows.

The following table illustrates the interaction between the Vivado runtime software and hardware when you set the Number of Capture Windows to more than 1 and the Trigger Position to 0.

Table 1. Number of Capture Windows > 1 and Trigger Position = 0
Software	Hardware
User Runs Trigger on the ILA core	Window 0: ILA is armed Window 0: ILA triggers Window 0: ILA fills capture window 0 Window 1: ILA is rearmed Window 1: ILA triggers Window 1: ILA fills capture window 1 …... Window n-1: ILA is rearmed Window n-1: ILA triggers Window n-1: ILA fills capture window n Entire ILA Capture Buffer is Full
Data is uploaded and displayed	The ILA core is rearmed such that it is ready to trigger on the clock cycle immediately following the last sample captured of the previous window.

The following table illustrates the interaction between the Vivado runtime software and hardware when you set the Number of Capture Windows to more than 1 and the Trigger Position to greater than 0.

Table 2. Number of Capture Windows > 1 and Trigger Position > 0
Software	Hardware
User Runs Trigger on the ILA core	Window 0: ILA is armed Window 0: ILA fills capture buffer up to trigger position Window 0: ILA triggers Window 0: ILA fills the rest of capture window 0 Window 1: ILA is rearmed Window 1: ILA fills capture buffer up to trigger position Window 1: ILA triggers Window 1: ILA fills capture buffer Window 1: ILA fills window 1 ...… Window n-1: ILA is rearmed Window n-1: ILA fills capture buffer up to trigger position Window n-1: ILA triggers Window n-1: ILA fills capture buffer Window n-1: ILA fills window n Entire ILA Capture Buffer is Full
Data is uploaded and displayed	Triggers could be missed between two windows since the ILA now has to fill the capture data up to the trigger position.