FPGA Fall-Back Configuration

Automatic Load of Save Configuration

FPGAs loose their configuration at power down. The configuration is loaded anew at each cold start (or optionally at a later point of time). On LightBridge 2 VCL, the FPGA loads its configuration from a BPI flash memory.

The BPI flash memory is divided into 8 partitions. One of partitions 1 - 7 contains the configuration the user wants to use (boot configuration and/or active configuration). To ensure the frame grabber is working reliably also in exceptional cases, partition 0 contains a fall-back configuration (Save configuration 1). The Save configuration is loaded automatically in cases the intended configuration (boot configuration or active configuration) cannot be used for FPGA configuration.

This way, you always have software access to the FPGA, i.e., you can always configure LightBridge 2 VCL with a fully functional configuration (applet).

When do such Situations Occur?

 

The most common cause why the intended configuration cannot be loaded is that LightBridge 2 VCL is disconnected from power while the BPI flash memory is loaded. Disconnection from power leaves the loading process unfinished. Afterwards, the FPGA cannot use the (incomplete) content of the BPI flash memory for configuration. The FPGA uses the Save configuration instead.

   

Configuration Switch

Any time, you can activate the Save configuration via the Configuration switch which is located directly on the rear side. This is the ultimate fall-back alternative in the very unlikely case the Save configuration is not loaded automatically.

Configuration Switch on LightBridge 2 VCL

To use the Configuration switch:

  1. Press the Configuration switch (using a sharp device like a needle).
  2. Reload the frame grabber's device driver, or re-start the host PC (warm start).

Re-Configuring/Re-Flashing LightBridge 2 VCL

As soon as the Save configuration is successfully activated, the according LED "SAVE MODE" (rear side) gives red light. This indicates LightBridge 2 VCL is available via software. You can now re-configure or re-flash LightBridge 2 VCL with a fully functional version of the applet you want to use for image acquisition. For flashing, you use the software tool microDiagnostics (see Flashing).

LED SAVE MODE, indicating that the Save configuration is the currently active FPGA configuration