Draft Specification for Sending And-Or Network Terms to the L1 Framework -------------------------------------------- Original Rev. 25-JUN-1996 Current Rev. 8-NOV-1998 The L1 Framework accepts L1 And-Or Network Input Terms in groups of 16. Each group of 16 Terms is accompanied by a Gap signal and a Strobe signal. Each positive transition on the Strobe signal indicates that there is new valid information on the 16 Term lines and the Gap line. A FIFO at the input to the L1 FW uses the positive edge of the Strobe signal to time when it latches the Term and Gap information that it receives from a Trigger System. The Strobe signal is generated by the Trigger System and sent to the L1 Framework for all 159 "ticks" during a turn around the accelerator. When the L1 FW pulls information from its side of this input FIFO it uses the Gap signal to verify that it is in proper alignment with the Trigger System that is feeding it the associated Term signals. The Term signals themselves are passed from the L1 FW side of this FIFO to the Framework And-Or Network. The Gap signal is asserted by the Trigger System and sent to the L1 Framework for those ticks when Trigger System is sending to the L1 FW Term signals that are the result of its analysis of detector data that comes from beam crossings that occurred during the once per turn Sync Gap. Based on timing markers that are part of the Serial Command Link, all Trigger Systems and the Detector Front-Ends know when Sync Gaps occur. The information on the Term lines and the Gap line should be valid 50 nsec before the positive edge of the Strobe signal and this information should remain valid for 50 nsec after this transition. The Strobe signal should remain asserted for about 50 nsec. The 16 Term signals, the Gap signal, and the Strobe are send to the L1 Framework on a 40 conductor twist and flat cable. The 16 terms are on the first 32 connector pins followed by the Gap signal, then a grounded pair, then the Strobe signal, and finally completing the 40 pin connector with a grounded pair. All signal levels are differential ECL with pull down current supplied from the sending end. The non inverted side of a differential pair is on an odd numbered connector pin and the inverted side of that signal is on the next higher even pin number. No additional information is send from the Triggers Systems to the L1 Framework. And-Or Network Input Terms to the L1 Framework Pin Out ------------------------------------------------------------- Pair Pin Number - Function Pin Number - Function ---- ------------------------ ----------------------- 1 1 Term_0 Non_Inv 2 Term_0 Inv 2 3 Term_1 Non_Inv 4 Term_1 Inv 3 5 Term_2 Non_Inv 6 Term_2 Inv 4 7 Term_3 Non_Inv 8 Term_3 Inv 5 9 Term_4 Non_Inv 10 Term_4 Inv 6 11 Term_5 Non_Inv 12 Term_5 Inv 7 13 Term_6 Non_Inv 14 Term_6 Inv 8 15 Term_7 Non_Inv 16 Term_7 Inv 9 17 Term_8 Non_Inv 18 Term_8 Inv 10 19 Term_9 Non_Inv 20 Term_9 Inv 11 21 Term_10 Non_Inv 22 Term_10 Inv 12 23 Term_11 Non_Inv 24 Term_11 Inv 13 25 Term_12 Non_Inv 26 Term_12 Inv 14 27 Term_13 Non_Inv 28 Term_13 Inv 15 29 Term_14 Non_Inv 30 Term_14 Inv 16 31 Term_15 Non_Inv 32 Term_15 Inv 17 33 Gap Non_Inv 34 Gap Inv 18 35 Gnd 36 Gnd 19 37 Strobe Non_Inv 38 Strobe Inv 20 39 Gnd 40 Gnd