The P0 feedback control system blurs the line between IOC and FPGA

The P0 Feedback system is a new design at the Advanced Photon Source (APS) primarily intended to stabilize a single bunch in order to operate at a higher accumulated charge. The algorithm for this project required a high-speed DSP solution for a single channel that would make adjustments on a turn-by-turn basis. A field programmable gate array (FPGA) solution was selected that not only met the requirements of the project but far exceeded them. By using a single FPGA, we were able to adjust up to 324 bunches on two separate channels with a total computational time of ∼ 6 x 109 multiply- accumulate operations per second. The IOC is a Coldfire CPU tightly coupled to the FPGA, providing dedicated control and monitoring of the system through EPICS [1] process variables. One of the benefits of this configuration is having a four-channel scope in the FPGA that can be monitored on a continuous basis.