VFAT readout electronics

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VFAT readout Block Diagram

A VFAT board from CERN is evaluated for use as a readout board to convert the GEM output analog signal to a digital signal.

BreakOutBox.jpgMedia:BreakOutBox.text

VFAT Board specifications

signals

LVDS signals to I/I module using 40 pin ribbon cable

LVDS

I2C signals

I2C

Breakout box specs (preliminary)

  • 6 inputs for ~1m ribbon cables from VFAT modules
  • 3-bit DIP switch to select I2C address range for each VFAT
  • Soft reset for each VFAT controlled via I2C expander chip
  • Shared hard reset line from Gumstix
  • Scan Mode switch
    • ScanIn connector (cascaded)
    • ScanOut connector (cascaded)
  • RJ45 port to gumstix box containing I2C and other signals:
    • Power (3.3 or 2.5V)
    • Ground
    • SDA
    • SCL
    • Hard Reset
    • Extra line for Link detection
  • 34 pin ribbon connector for LVDS signals
  • LEMO connector for LVDS trigger input
  • LEMO connector for LVDS Master Clock
  • I2C expander(s) for status LEDs (socketed)
  • Status LEDs:
    • Power (from I2C line)
    • I2C connect (flashing through I2C expand)
    • Power for each VFAT (feedback through common pins on VFAT board?)
    • Hard Reset LED
  • Clear UpsetReg (SEU counter) via I2C expand

Ribbon cable pinouts

# Name Value Test rig color
Primary/Second
B1 DGND Digital Ground Black/Grey (shared)
A1 DVDD +2.5V Red/Grey (shared)
B2 SDA I2C Data Green/Yellow
A2 SCL I2C Clock Yellow/Green
B3 DGND Digital Ground Black/Grey (shared)
A3 DVDD +2.5V Red/Grey (shared)
B4
A4
B5 I2C ADDR 2 I2C Address Most White/Blue
A5 I2C ADDR 1 I2C Address Middle White/Orange
B6 I2C ADDR 0 I2C Address Least White/Green
A6 REH-S Soft Reset (Program saved) White/Grey
B7
A7 REH-B Hard Reset Grey/White
..............
B22 DGND Digital Ground??
A22 SCAN E
B23 AGND Analog Ground
A23 AVDD 2.5V Grey/Red
B24 AGND Analog Ground
A24 AVDD 2.5V Grey/Red
B25 AGNDD Analog Ground?? Grey/Black
A25 AVDD 2.5V Grey/Red


The PC board-mount socket for the cable is ERNI 154765 for reel or ERNI 063197 for tube packaging.
The cable crimp-ons are ERNI 024403 or premade cables 300mm long are ERNI 173795