1. HF Phase-1 Upgrades QIE RM-uHTR protocol proposal Marcelo Vicente (University of Wisconsin-Madison) 1

2. Current Protocol Two main issues: Lack of error checking and realignment mechanisms. Goal: Improve long term reliability and mitigate possible instabilities. Byte\Bit76543210 0K28.5 (0xBC) 1TDCE3TDCE2TDCE1TDC0Link IDBC0 2CapId 3CapId 2CapId 1CapId 0 3QIE ADC 0 4QIE ADC 1 5QIE ADC 2 6QIE ADC 3 7LE TDC 3 [5:4]LE TDC 2 [5:4]LE TDC 1 [5:4]LE TDC 0 [5:4] 8LE TDC 3 [3:2]LE TDC 2 [3:2]LE TDC 1 [3:2]LE TDC 0 [3:2] 9LE TDC 3 [1:0]LE TDC 2 [1:0]LE TDC 1 [1:0]LE TDC 0 [1:0] 10TE TDC 1TE TDC 0 11TE TDC 3TE TDC 2 2

3. Packet improvements BC0 included in the header as a different K-character. CRC-4-ITU included as the last 4 bits of each packet. Link ID moved to a test mode, only required for commissioning. Byte\Bit76543210 0K28.5 (0xBC) 1TDCE3TDCE2TDCE1TDC0Link IDBC0 2CapId 3CapId 2CapId 1CapId 0 3QIE ADC 0 4QIE ADC 1 5QIE ADC 2 6QIE ADC 3 7LE TDC 3 [5:4]LE TDC 2 [5:4]LE TDC 1 [5:4]LE TDC 0 [5:4] 8LE TDC 3 [3:2]LE TDC 2 [3:2]LE TDC 1 [3:2]LE TDC 0 [3:2] 9LE TDC 3 [1:0]LE TDC 2 [1:0]LE TDC 1 [1:0]LE TDC 0 [1:0] 10TE TDC 1TE TDC 0 11TE TDC 3TE TDC 2 Byte\Bit76543210 0K28.5 (0xBC) / K28.3 (0x7C) when BC0 1TE TDC 1TE TDC 0 2CapId 3CapId 2CapId 1CapId 0 3QIE ADC 0 4QIE ADC 1 5QIE ADC 2 6QIE ADC 3 7LE TDC 3 [5:4]LE TDC 2 [5:4]LE TDC 1 [5:4]LE TDC 0 [5:4] 8LE TDC 3 [3:2]LE TDC 2 [3:2]LE TDC 1 [3:2]LE TDC 0 [3:2] 9LE TDC 3 [1:0]LE TDC 2 [1:0]LE TDC 1 [1:0]LE TDC 0 [1:0] 10TE TDC 3TE TDC 2 11CRC-4-ITUTDCE3TDCE2TDCE1TDC0 3 Current protocol:Revised protocol:

4. Realignment Add an IDLE period during TCDS veto gap (BXs 3529-3563) on every orbit. Have 4 pre-sample of digis before BC0 and 4 IDLE packets before that. Avoids writing complicated realignment code on the uHTR. Realignment is done automatically every orbit, similar to the legacy system. 4

5. Underlying question Is the data during the ‘dark’ gap period (BXs 3556-3559) relevant? All triggers will be vetoed by TCDS during those crossings. 5

6. Test mode 1 Propagation of unique ID and BCN counter. Already present, with the exception of the CRC. 6 Byte\Bit76543210 0K28.5 (0xBC) / K28.3 (0x7C) when BC0 1Minor Version 2Unique ID [7:0] 3Unique ID [15:8] 4Unique ID [23:16] 5Unique ID [31:24] 6Unique ID [39:32] 7Unique ID [47:40] 8Unique ID [55:48] 9Unique ID [63:56] 10Bunch crossing number counter [7:0] 11CRC-4-ITUT/BFiber NumberBC0

7. Test mode 2 80-bits of programmable words, allowing propagation of fiber ID codes. Easier commission of fibre installation at P5. 7 Byte\Bit76543210 0K28.5 (0xBC) / K28.3 (0x7C) when BC0 1Custom word 0 [7:0] 2Custom word 0 [15:8] 3Custom word 1 [7:0] 4Custom word 1 [15:8] 5Custom word 2 [7:0] 6Custom word 2 [15:8] 7Custom word 3 [7:0] 8Custom word 3 [15:8] 9Custom word 4 [7:0] 10Custom word 4 [15:8] 11CRC-4-ITUT/BFiber NumberBC0