1. 1 Control & Readout Emulator for the Preshower Electronics (CREPE) P.Vichoudis, CERN

2. 2 CREPE is a portable FPGA-based FE clocking/triggering/control/readout system Introduction KEY FEATURES: - Internal/External clock operation - Internal/External triggering operation (incl. powerful trigger pattern generation) - Electrical/Optical control FE interface - Optical FE readout interface (up to 4ch.) - Operated by a single USB connection (max data rate 8Mbps) - For on-line readout, it supports an S-LINK transmitter (max data rate 2.4Gbps) - Device Drivers (for linux) - LabVIEW (for linux) template applications P.Vichoudis, CERN

3. 3 Simplified Diagram P.Vichoudis, CERN

4. 4 InterfaceToThroughFor USBPCUSB cableGeneral CREPE operation (FE configuration, data transfer to PC etc) LEMOTest Beam Clk/Trigger LEMO cable (2.5V, 50 ohm) External CREPE clocking & triggering (clock:40MHz, min. trigger pulse width:50ns) 4-ch optoTRxFEStandard CTRL Optical Bundle FE Clocking, Fast commands (L1A, Resync etc), Slow control 3-ch optoRxFEStandard DATA Optical Bundle FE Readout CREPE for Test Beam using only USB (1/2) P.Vichoudis, CERN

5. 5 CREPE for Test Beam using only USB (2/2) P.Vichoudis, CERN Trigger Window Buffer Readout Limitation: The system cannot receive events and send them to PC the same time. Operation 1. Arm the system – to be ready to accept triggers. 2. It will accept up to a certain number of events (at any rate) that fill the 2048-word buffers. 3. The buffers must be readout by the PC. No triggers should be sent in the buffer readout period. 4. Repeat steps 1-3 Arm - Trigger Window period: depends on the event rate & number of event that can fit in the buffer. - Buffer readout time: depends on the hardware access transaction time through USB. It is also system depended (Operating system/PC speed etc). The fastest time that can be achieved for reading out 1 CREPE’s buffer (1 data channel): BRT min = [usb transaction overhead] + [data size] / [USB data rate] = BRT min = ~2ms + 2048 x 32bit / (2.5Mbit/s) = ~27ms. Note: the USB data rate measured in the lab is 2.5Mbit/s (instead of 8Mbit/s stated in the USB chipset manual).

6. 6 CMS IN 2005/049 : “The control & readout emulator for the Preshower electronics (CRÊPE): users guide” LECC2004 Proceedings: “A flexible stand-alone testbench for facilitating system tests of the CMS Preshower” P.Vichoudis, CERN Documentation