1. Status of Integration of Busy Box and D-RORC Csaba Soós ALICE week 3 July 2007

2. 2Cs. Soos Introduction The front-end must be able to indicate, when it cannot accept more trigger, in order to avoid overflow in its readout buffers. In the traditional scheme, the front-end generates a BUSY signal, which is connected – either directly, or through the FANIN module – to the LTU. Some sub-detectors (TPC, TRD, PHOS, FMD), due to dense cabling, cannot implement the traditional scheme. The Busy Box concept has been developed in collaboration with the University of Bergen, Norway.

3. 3Cs. Soos Topology DAQ Readout Receiver Card (D-RORC) Front-end Electronics RCU cards DAQ Readout Receiver Card (D-RORC) Front-end Electronics RCU cards DAQ Readout Receiver Card (D-RORC) Front-end Electronics RCU cards DAQ Readout Receiver Card (D-RORC) Front-end Electronics RCU cards DAQ Readout Receiver Card (D-RORC) Front-end Electronics RCU cards Local Trigger Unit (LTU) Busy Box LVDS DDL TTC Busy

4. 4Cs. Soos Data transmission Physical layer LVDS 350 mV on 100 Ω 3.5 mA 2 inputs, 2 outputs (RJ-45 connector) Link layer Asynchronous message (no CLK distribution) 40 Mbps rate Message format (RS232-like) 2 start bits, 16 data bits, 1 parity, 1 stop bit Protocol 1-word request from the Busy Box 3-word reply from the D-RORC The messages shall contain a request ID

5. 5Cs. Soos Request: new ID Communication DCS BBOXD-RORCRCU LTU 1 2 1 2 Sub-event 1 Sub-event 2 Reply: no ID Reply: event ID 1 Request: new ID Compare OK Request: new ID Reply: event ID 2 Compare OK used++ used-- 3 4 5 6 3 4 5 6 used++ XOFF Busy TTC Request: new ID Reply: no ID Request: new ID Reply: no ID Request: new ID Reply: no ID

6. 6Cs. Soos Test system in the DDL lab Trigger crate Busy Box TTC BUSY TTC LVDS DDL

7. 7Cs. Soos Test system in the RCU lab Trigger crate Busy Box TTC BUSY TTC LDC + D-RORC DDL LVDS

8. 8Cs. Soos Achievements The communication between the Busy Box and the DRORC has been tested it is reliable, but we should improve to make it more robust The complete chain, including the LTU, DDG as data source, DRORC, and Busy Box has been tested long runs (several hours without interruption) The complete chain, including one RCU (emulating the PHOS readout), DRORC and Busy Box has been tested long runs (4-5 million events) at 1 kHz The complete chain, including 3 RCUs, 3 DRORCs and Busy Box is being tested short runs at 400 Hz problem is being investigated

9. 9Cs. Soos To be done Finish the tests in the RCU lab perform stable runs with 6 RCUs Integrate the Busy Box into the PHOS readout install the Busy Box in the PHOS lab test the system with several RCUs at the highest possible rate Improve communication protocol between the Busy Box and D-RORC the protocol should recover from eventual communication problems Implement the control of the Busy Box at the level of the DCS

10. 10Cs. Soos Thank you

11. 11Cs. Soos Request: new ID

12. 12Cs. Soos Reply: no ID

13. 13Cs. Soos Reply: event ID