Difference between revisions of "VFAT readout electronics"

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[[Image:VFAT_WebinterfaceScreenshot.jpg | 200 px]]
 
[[Image:VFAT_WebinterfaceScreenshot.jpg | 200 px]]
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 +
==Flipbit command interface==
 +
Once logged into the Gumstix, I2C registers on the VFAT can be modified using the flipbit interface. The flipbit.arm program takes input on standard input as shown in the following example:
 +
<pre>echo p 41 2 on | flip bit</pre>
 +
=====Field 1:=====
 +
*"p" is for primary register.
 +
*"e" is for extended register.
 +
=====Field 2:=====
 +
*if "p" i2c address of the register to be modified. ''Must be between 0 and 128 inclusive''
 +
*if "e" the value of the extended register to modify. ''Must be between 0 and 256 inclusive''
 +
=====Field 3:=====
 +
*the bit (counting from 0=least significant) to modify. ''Must be between 0 and 7 inclusive''
 +
=====Field 4:=====
 +
*"on" turn the bit on.
 +
*"off" turn the bit off.
 +
*"flip" flip the bit. (on if it was off, off if it was on)
 +
 +
 +
Using standard input allows commands to be chained. The following example toggles bits 6 and 7 of address 64:
 +
<pre>echo "p 64 7 flip p 64 6 flip" | flipbit.arm</pre>
 +
 +
If a # is used at the beginning of a line or after the standard arguments, the rest of the line is ignored. This is helpful when commands are stored in a file for later. Contents of an example cal.fb file:
 +
<pre>
 +
#Turns on common calibration settings
 +
 +
#toggle calmode registers
 +
p 64 6 flip #CalMode<0>
 +
p 64 7 flip #CalMode<1>
 +
 +
#switch a few channels into calibration mode
 +
e 2  7 on #channel 2
 +
e 3  7 on #channel 3
 +
</pre>
 +
Using that cal.fb file:
 +
<pre>
 +
# flipbit.arm < cal.fb
 +
Using mode p
 +
Using address 64
 +
Using bit 6
 +
Using action flip
 +
 +
Using mode p
 +
Using address 64
 +
Using bit 7
 +
Using action flip
 +
 +
Using mode e
 +
Using address 2
 +
Using bit 7
 +
Using action on
 +
 +
Using mode e
 +
Using address 3
 +
Using bit 7
 +
Using action on
 +
</pre>
  
 
=I/O VME modules=
 
=I/O VME modules=

Revision as of 19:00, 26 August 2008

This page describes the GEM detector readout system for the Qweak experiment. The system has four components, the VFAT readout card from CERN, a signal breakout box, a Gumstick I2C control computer, and an I/O VME module to record the LVDS output from the VFAT card.

VFAT readout Block Diagram

The diagram below describes the detector readout electronics for a GEM detector instrumented with 6 VFAT boards. Each VFAT board has 128 radout channels which are output through a single LVDS data line in series. 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.jpg


Media:BreakOutBox.text




Target View:

Dimensions:
Width: 7.5"
Height: 4.5"


BreakOutBox targetview.jpg

VFAT Board specifications

Photos of the top and bottom side of the VFAT card are shown below. The top side has a 50 pin connector which goes to the breakout box to separate I2C control signals and LVDS data I/O signals. The bottom side attaches to the GEM detector readout board via a 130 pin header connector.

VFATtop.jpgVFATbottom.jpg
  • 40 MHz sampling
  • 128 channels
  • can store up to 128 triggered events
  • 0.25 [math]\mu[/math]m CMOS
  • designed to withstand 100 MRad
  • Single Event Upset protection using triple logic flip flops testable via a scan chain
  • I2C control
  • LVDS output

Signals

LVDS Signals to I/O module using 34 pin ribbon cable

LVDS

National Semiconductor LVDS site

LVDS signals should be able to go 10 m

Media:Image:LVDS_EvaluationKit.pdf

[National Semiconductor suggests 15 m in section 2.5]


change to CAT 5 cable and you may be able to hit 80 m for 40 Mb/s

Media:LVDS_Products.pdf

I2C signals

I2C (Can travel 8 m)

Breakout box specs (preliminary)

The breakoutbox is a circuit board with no active elements that separates the I2C command signal lines from the LVDS data I/O lines. The box is designed to support 6 VFAT readout cards. The box is being designed to be mounted on the detector rotator. All 6 VFAT cards will have their signal lines go into the break out box. The I2C lines will then go our of the breakout box along an RJ45 standard ethernet cable. The LVDS lines will exit though a standard 34 pin ribbon cable(Connector type Robinson Nugent P50E-068-P1-SR1-TG).

  • 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

# VFAT
pin #		 Name Value Test rig color
Primary/Second
B1 DGND Digital Ground Black/Grey (shared)
A1 DVDD +2.5V Red/Grey (shared)
B2 168 SDA I2C Data Green/Yellow
A2 167 SCL I2C Clock Yellow/Green
B3 DGND Digital Ground Black/Grey (shared)
A3 DVDD +2.5V Red/Grey (shared)
B4 162 DACo-V DAC output Volt
A4 163 DACo-I DAC output Current
B5 164 I2C ADDR 2 I2C Address Most White/Blue
A5 165 I2C ADDR 1 I2C Address Middle White/Orange
B6 166 I2C ADDR 0 I2C Address Least White/Green
A6 169 REsB Soft Reset (Program saved) White/Grey
B7 170 ForceRehOff ?? bond to grnd
A7 171 REhB Hard Reset Grey/White
B8 173 MCLKB (-) Orange/Purple
A8 174 MCLK (+) Purple/Orange
B9 175 T1B (-) Green/Purple
A9 176 T1 (+) Purple/Green
B10 177 ScanOut Brown/Purple
A10 178 ScanIn Purple/Brown
B11 180 DataValidB (-) Grey/Purple
A11 181 DavaValid (+) Purple/Grey
B12 182 DataOutB (-) Blue/Black
A12 183 DataOut (+) Black/Blue
B13 184 SB8 (-) Orange/Black
A13 185 S8 (+) Black/Orange
B14 186 SB7 (-) Green/Red
A14 187 S7 (+) Red/Green
B15 188 SB6 (-) Orange/Red
A15 189 S6 (+) Red/Orange
B16 190 SB5 (-) Blue/Red
A16 191 S5 (+) Red/Blue
B17 192 SB4 (-) Grey/Yellow
A17 193 S4 (+) Yellow/Grey
B18 194 SB3 (-) Brown/Yellow
A18 195 S3 (+) Yellow/Brown
B19 196 SB2 (-) Orange/Yellow
A19 197 S2 (+) Yellow/Orange
B20 198 SB1 (-) Blue/Yellow
A20 199 S1 (+) Yellow/Blue
B21 DGND Digital Ground
A21 DVDD +2.5V
B22 DGND Digital Ground
A22 179 ScanEn Scan Mode Enable
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

DF test Pattern

DFtestPattern.png

Gumstick I2C controller

The gumstix motherboard used is the verdex XL6P. It has a 600MHz Marvell XScale processor, 128MB of RAM, and 32MB of flash.
More information: Gumstix
GumstickandVFAT.jpg

Web Interface

The I2C commands from the Gumstick to the VFAT board may be controlled through the web interface (if it is turned on)

VFAT WebinterfaceScreenshot.jpg

Flipbit command interface

Once logged into the Gumstix, I2C registers on the VFAT can be modified using the flipbit interface. The flipbit.arm program takes input on standard input as shown in the following example: 

echo p 41 2 on | flip bit
Field 1:
  • "p" is for primary register.
  • "e" is for extended register.
Field 2:
  • if "p" i2c address of the register to be modified. Must be between 0 and 128 inclusive
  • if "e" the value of the extended register to modify. Must be between 0 and 256 inclusive
Field 3:
  • the bit (counting from 0=least significant) to modify. Must be between 0 and 7 inclusive
Field 4:
  • "on" turn the bit on.
  • "off" turn the bit off.
  • "flip" flip the bit. (on if it was off, off if it was on)


Using standard input allows commands to be chained. The following example toggles bits 6 and 7 of address 64: 

echo "p 64 7 flip p 64 6 flip" | flipbit.arm

If a # is used at the beginning of a line or after the standard arguments, the rest of the line is ignored. This is helpful when commands are stored in a file for later. Contents of an example cal.fb file: 

#Turns on common calibration settings

#toggle calmode registers
p 64 6 flip #CalMode<0>
p 64 7 flip #CalMode<1>

#switch a few channels into calibration mode
e 2  7 on #channel 2
e 3  7 on #channel 3

Using that cal.fb file: 

# flipbit.arm < cal.fb
Using mode p
Using address 64
Using bit 6
Using action flip

Using mode p
Using address 64
Using bit 7
Using action flip

Using mode e
Using address 2
Using bit 7
Using action on

Using mode e
Using address 3
Using bit 7
Using action on

I/O VME modules

Struct SIS3610

Structsis3610.jpg

V1495 FPGA

CAEN V1495.jpg Speed tests Cable




Parts List

Parts List

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