NXscope Startup Application Note
- Julia DAUMAL (Unlicensed)
- pnguon
List of figures
NXCore GUI setup page for NXcope_Startup
NXscope_Startup overview
NXscope_Startup allows to capture a continuous data sequence at the FPGA startup (power-on). NXscope_Startup can be implemented in NG-MEDIUM and NG-LARGE.
It’s based on the standard version of NXscope, with an additional module able to sample data at high speed without requiring any user’s action. Only a simple 1 to 4-input boolean condition is required to launch the acquisition.
NXscope_Startup uses a two-step capture process, each step using its own memory :
Fast capture RAM (user’s defined width and depth). The capture is automatically done on a simple trigger condition (1 to 4-input boolean function). The supported capture frequency clock can reach up to 200 MHz. After the first stage capture is done, the contents of this first level memory can be transferred to the second level RAM, which is part of a standard version of NXscope.
The transfer of captured data to the NXscope RAM is launched when the “TRIG_ARMED” is high (when the user launches the “capture” command with the NXboard GUI). When the data transfer is complete, “DONE” goes high and the data are read by ANGIE via the buried JTAG.
The results can be then analyzed and displayed, just like with the standard NXscope.
The figure below shows a simplified NXscope_Startup block diagram.
The NXscope_Startup uses twice the amount of memory, comparing with the standard version of NXscope.
NXscope_Startup user’s inputs and outputs :
The following table shows the list on NXscope_Startup inputs and outputs.
Note that JTAG pins are buried into the NXscope_Startup IP Core.
Name | Width | Mode | Comments |
|---|---|---|---|
DIN_LINES | 1 to 24 | In | Signals to be captured |
STARTUP_TRIGGER_LINES | 1 to 4 | In | 1 to 4 trigger lines for simple boolean condition (1 to 4-bit value) |
CLK_CAPT | 1 | In | Capture clock (can support frequencies up to 200 MHz – check timing reports for realistic performance) If “CLK_CAPT” is available before the trigger condition is met, samples can be captured before the trigger condition. |
CLK_READ | 1 | In | Secondary clock for data transfer management between the STARTUP_FAST_CAPTURE_RAM and the embedded NXscope RAM. CLK_READ can be asynchronous from CLK_CAPT, and doesn’t doesn’t need to be at high frequency. Any 20 to 100 MHz clock can be used as CLK_READ |
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PRE_CAPTURE_DONE | 1 | Out | Goes high when the trigger condition has been met. The capture in the first RAM level is done imediatelly, then NXscope_Startup waits for a capture command to transfer the captured data to the dump file via ANGIE USB-JTAG adapter.. |
TRIG_ARMED | 1 | Out | Once the STARTUP_FAST_CAPTURE_RAM has been filled, the user can launch the NXscope capture thanks to the “nxboard” GUI. TRIG_ARMED goes high and launches the transfer between both RAM sets. |
DONE | 1 | Out | When the data transfer is complete, DONE goes high, and NXscope starts reading by JTAG via ANGIE USB adapter to generate the dump file for waveform display. |
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NXscope_Startup user’s parameters (nxscope GUI)
The next figure shows the NXcore GUI setup page for NXscope_Startup generation.
The following table summarizes the NXscope_Startup parameters, including allowed ranges and additional comments.
Parameter name | Allowed values | Comments |
|---|---|---|
Entity name | Any user’s name (VHDL compliant) | Note that NXcore allows to define independent names for the entity and the VHDL file. The VHDL file name can be defined |
Input line count | Range 2 to 240 | Memory width (same as NXscope) |
Capture_depth | 2K, 4K, 6K, 12K, 24K or 48K | Memory depth (same as NXscope) |
Pre-trigger samples | 1 to 1000 | Can be used to store some samples before the NXscope_Startup condition is met. Make sure the capture clock is available during the specified amount of Pre-trigger samples to get the correct behavior. |
Trigger line count | 1 to 4 | Allows 1 to 4-bit trigger condition |
Trigger value | ‘0’ or ‘1’ can be defined for each trigger input line | Value to be detected for trigger. Ex for 4 Trigger line count : “0110”. Only ‘0’ and ‘1’ values are supported. |
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