The CMS CSC group have asked for some help testing the GBTx interface on their xDCFEB boards, which are due to go into production soon (mid-2018). We held a kick-off meeting on 2018-06-06.

Document SVN: ​http://gauss.bu.edu/svn/cms-csc

2018-11-02 Getting started

Met briefly with Indara, Ben. Reviewed plan:

• Develop simple FC-7 firmware with circular buffers for Tx and Rx on one GBT link. Include useful status registers and trigger on specific bits/patterns to stop capture.
• Move the VLDB to the CMS lab with USB attachment to one of the CMS machines
• Give Indara an account so she can install the required software

GBTx I/O mapping (incomplete):

GBTX DIO	Name	Function
0-15	gbt_prg_data_	Configuration data to Virtex D0 to D15
16	gbt_prg	Virtex PROGRAM_B (through some logic)
17	gbt_prg_ena	Virtex PROGRAM_B enable when '1'
18	gbt_override	clock override (??)
19	gbt_sel_gbt_xprm	select GBT configuration source (??)
20	gbt_sel_8b_16b	??
21	gbt_sel_mstr_slave	Virtex mode M1
22	gbt_sel_cclk_src	??
23	gbt_sel_gbt_cclk_src	??

Draft spec / documentation for FC-7 firmware: DCFEBTestFirmware

2018-09-25 Collecting documentation

• ​Versatile Link project
• ​VLDB Demo Board

Looking at XDCFEB schematic:

• LVDS cable w/ alternate JTAG on page 7
• JTAG on page 10, 11
• Most GBTX and FPGA config interface are on pages 44-45 (last pages).

2018-09-25 meeting notes:

What we need:

• XDCFEB documentation if any
• XDCFEB layout info (just to identify parts, etc). Gerbers would be fine.
• An xDCFEB board plus connectors, etc power supply
• (we have an FC-7)
• FMC mezzanine with high speed SERDES to SFP (commercial, long lead time?)
• Eventually: base firmware for XDCFEB

2018-06-06 meeting notes:

Meeting participants: Indara (BU), Ben Bylsma (OSU), Stan Durkin (OSU), Darien Wood (Northeastern)

Other collaborators: Evaldas Juska and Jason (TAMU), also UCLA, UCSB, UC Davis and others

• DCFEB TWiki page: ​https://twiki.cern.ch/twiki/bin/viewauth/CMS/CSCdescriptionDCFEB
• xDCFEB schematic: ​http://gauss.bu.edu/svn/cms-csc/Docs/xdcfeb_v3a_schematic.pdf
• xDCFEB slides: ​http://gauss.bu.edu/svn/cms-csc/Meetings/2018-06-06/xDCFEB_status5_CMS_Week.pptx

The general plan is to test the production xDCFEB boards at OSU using a VME setup with back-end boards. The xDCFEB has a GBTx ASIC on board which is used to access the configuration interface of the Virtex-6 (XC6VLX130T). They would like us to devise a simple test of this interface. The GBTx has an uplink fiber too but currently it is not foreseen to use this but we should plan to test it as well.

We could write firmware and software for an FC-7 to accomplish this. The bitstream for the XC6VLX130T is 43,719,776 bits, which is larger than the 30Mb or so of block RAM on the 7K420 on the FC-7, but there is a DDR3 on the FC-7 too which could hold the bitstream.