RPC Electronics: Technical Trigger

Annual Review Cern -June 13th, 2006 F. Loddo I.N.F.N. Bari

RPC Electronics: Technical RPC Electronics: Technical TriggerTrigger

Flavio Loddo

I.N.F.N. Bari

On behalf of the RPC-Trigger group

Outline:

•RPC-based Technical Trigger

• Principles of operation

• Implementation

• MTCC readiness


RPC Technical TriggerRPC Technical Trigger

Goal of this project is to produce an RPC-based cosmic ray trigger for the Commissioning of RPCs, the Cosmic Challenge and later

running of CMS as Technical Trigger

The project started recently, when electronics and cabling in the cavern were defined and frozen

↓

Use existing infrastructure (as much as possible) and don’t introduce major modifications to the existing electronics (Link Boards)


Block Diagram of RPC Electronics full Block Diagram of RPC Electronics full chainchain


RPC Cosmic trigger

Phase I: Sector Trigger for testing RPC (and DT) during Commissioning and MTCC

Phase II: Technical trigger to be used during off-beam periods for detector calibration

RBC (RPC Balcony Collector)

RBC + TTU (Technical Trigger Unit)




LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

1 RBC/ 2 sectors

UXC area

Barrel Wheel

USC area

30 Optical Fibers

Receivin

g

pan

el

TTU

TTU

TTU

TTU

TTU

ReadoutCrate

6 Fibers/wheel

Fiber


Technical Trigger Unit


RBC ImplementationRBC Implementation

•The RPC signal cables (LVDS) are connected to the Link Boards (LB) for synchronization, data compression and optical conversion

•Each LB reads 96 strips (1 bi-gap = half/chamber) and can produce 1 OR to be used for our goal

•Each LBBox (LBB) houses 13 or 15 (sect. 4 and 10) LBs of 1 Barrel Sector

•The LBBs are distributed in the 30 periphery racks in groups of 2:

one odd sector and one even sector

We can house 1 RBC/rack 1RBC/2 sect 30 RBCs in total


RPC LBBoxRPC LBBox

•LBB's slots 11, 12, 13 are always free in barrel•CSC connector is not used in barrel•at least one I2C output is not used on backplane

RBC will be located on slot 12 of LBB of all odd sectorsRBC_fake will be located on slot 12 of LBB of all even sectors



RBC Main FeaturesRBC Main Features

•Receive 2x13 (or 15) ORs from LB (LVDS)

(OR of 96 strips (1 bi-gap = half RPC))

•Mask noisy/dead Ors

•Produce Sector Trigger (LVDS), with selectable Majority level

•Force selected ORs to be in the coincidence, to

increase trigger selectivity

• Introduce latency for synchronization

•I2C Interface

•Transmit input OR optically to Counting Room (GOL)

RB4

RB3

RB2_OUT

RB2_IN

RB1_OUT

RB1_IN

Generic Barrel Sector


RBC PCB LayoutRBC PCB Layout

FPGA

Optical transceiver

Z-Pack Conn.

GOL •10 Layers PCB 14x14 cm2

(small board to save money)

• to be housed on Mother Board, fitting LBBox dimensions

JTAG Conn.


RBC Motherboard LayoutRBC Motherboard Layout

Backplane connector:•3.3 V•2.5 V•GND•I2C

Low profile connector (5 mm) to connect RBC to Motheboard

Front side


QuantitiesQuantities

• 30 RBC (10 layers PCBs 14x14 cm2)

• 30 RBC Mother Boards (2 layers PCBs 16x46 cm2)

• 30 RBC_FAKE (4 layers PCBs 2x4 cm2)

• 60 RBC_FP1 (4 layers PCBs 18x14 cm2)

• 60 RBC_FP2 (4 layers PCBs 18x14 cm2)


Two RBC (RPC Balcony Collector) can

be used during the MTCC to provide two

Cosmic Triggers to the LTC (or PSB),

based on the coincidence of half

chamber ORs coming from the LBs

RPC Technical Trigger for MTCCRPC Technical Trigger for MTCC

W+2: Sect. 10 Sect. 11

Sect.10-11 patternsOR

Trig_+2

W+1: Sect. 10 Trig_+1


• Because of long distance (150 m) between Detector and “Green Barrack” during MTCC, we could send the Technical Trigger in LVPECL, that is more robust than LVDS and introduce optocouplers to cut ground loops

• This configuration was succesfully tested in Bld. 904 with both LTC and

PSB

• Preliminary latency estimate: 45 bx

RBC testing for MTCCRBC testing for MTCC

RBCLVDS-

LVPECL Transceiv.

LVPECL Receiv.

LVDS Driver

LTCOr PSB

150 m (shielded twisted cable)


RPC Technical Trigger RPC Technical Trigger ImplementationImplementation

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

LBBox

RBC

LBBox

UXC area

Barrel Wheel

USC area

30 Optical Fibers

Receivin

g

pan

el

TTU

TTU

TTU

TTU

TTU

6 Fibers/wheel

Fiber


Technical Trigger Unit

To

Glo

bal

Tri

gg

er


TTU (TTU (Technical Trigger Unit) Block ) Block DiagramDiagram

•Receive optical link from RBCs

•Combine ORs from 1 Wheel and produce Wheel Cosmic Trigger

•To be housed in the counting room

Wheel Trigger

HFBR-5720TLK2501 6x16 bit dataTLK2501TLK2501TLK2501TLK2501

ProgrammableMajority Unit

or Pattern Recognition

Processor

TTCrxQPLLVME InterfaceVME Interface

Comm. line

Deskewed HF clock

LHC Clock

6 Fibers 6x16 bit data


RPC Trigger Board as TTURPC Trigger Board as TTU

These functions are performed by the RPC Trigger Board:• TTU needs:

1. 30 signals from detector: 1.6 GHz GOL drive multimode fiber;

2. each fiber transfers 26 or 28 bits @ 40 MHz;

3. Signals must be synchronized;

4. Pattern logic to make cosmic trigger

• RPC Trigger Board offers:

1. 18 inputs: 1.6 GHz GOL driven multimode fiber;

2. Opto synch FPGA for every 3 optical inputs;

3. Transmission to PAC mezzanine boards (VHDL code)

4. VHDL code for Internal Interace (for VME driven internal bus and software tools)


RPC Trigger Board as TTURPC Trigger Board as TTU

1. 3 TBs can be used to cover the whole Barrel, using 12 links per TB

2. The Stratix2 PAC mezzanine board gives very big space for algorithm (1 or 2 should be enough)

3. TTU custom backplane (for TTCrx and to send out the Trigger) but be designed, but can be derived from the design of TB backplane


ConclusionsConclusions

The RPC Technical Trigger project is under progress:

• 3 RPC Balcony Collector (RBC) prototypes are available for MTCC

• The full production is expected to be available before the end of 2006

• The design of the new firmware for the Trigger Board-TTU will start in few weeks

Documents

RPC Electronics: Technical Trigger