Trigger Distribution Module

The trigger distribution module (TDM) provides a flexible mechanism for distributing triggers and pulse sequence steering information across an APS2 crate. Since we expect our users to have diverse requirements for distributing steering information, we have decided to deliver the TDM as a reconfigurable device with a basic firmware that will satisfy certain needs.

Base Functionality

The base firmware delivered with the TDM will distribute signals captured on its front-panel interface to all APS2 modules connected by SATA cables. Port T8 is used as a ‘valid’ signal to indicate that data is ready to capture on T1-T7. On the rising of a signal on T8, the signals on T1-T7 are captured into a 7-bit trigger word which is immediately distributed across the APS2 crate. Each of the trigger ports T1-T8 drives a comparator with a programmable threshold. The base firmware fixes this threshold at 0.8V.

Building Custom Firmware

The TDM firmware source may be found here: https://github.com/BBN-Q/APS2-TDM

To get starting creating your own APS2 TDM firmware, you need a copy of Xilinx Vivado 2015.1 (the free Webpack edition is sufficient). Note that there are more recent versions of Vivado, but that the firmware source refers to specific versions of Xilinx IP cores, and it may be necessary to convert these for use with later Vivado versions. The APS2 TDM firmware relies upon one not-free Xilinx IP Core, the Tri-Mode Ethernet Media Access Controller, or TEMAC: http://www.xilinx.com/products/intellectual-property/temac.html

You can build the firmware without buying a TEMAC license, but the controller will stop functioning ~8 hours after loading the image, and you will be forced to power cycle the APS2 TDM to continue. We recommend purchasing a project license for the Xilinx TEMAC if you plan to build your own TDM firmware.

Refer to the README in the APS2-TDM firmware source for instructions on creating a Vivado project.