Towards a Platform for Widespread Embedded Intelligence - ERCIM
Towards a Platform for Widespread Embedded Intelligence - ERCIM
Towards a Platform for Widespread Embedded Intelligence - ERCIM
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62<br />
R&D AND TECHNOLOGY TRANSFER<br />
Detector Technology<br />
Data Acquisition in Scientific Applications<br />
by Rob Halsall<br />
Large scale scientific instrumentation systems <strong>for</strong> particle physics research at<br />
CERN are currently being deployed with many millions of sensor channels and<br />
Data Acquisition (DAQ) rates of the order of 100s of GByte/s. These systems,<br />
consisting of many racks of large <strong>for</strong>mat electronics modules, are typically<br />
implemented using custom digital logic in Field Programmable Gate Array (FPGA)<br />
devices. Installed in under ground caverns, closely coupled to massive detectors<br />
and networked to PC processing farms, these systems could be regarded as very<br />
large examples of embedded systems.<br />
In other science areas (eg Synchrotron<br />
Radiation (SR), Neutron beams) there<br />
are growing requirements to move to<br />
similar detector technology. Although<br />
on a smaller scale this is resulting in high<br />
sample rates and channel counts with a<br />
dramatic increase in the data rates over<br />
previous systems from around 100<br />
MByte/s to 10 GByte/s.<br />
Figure 1:<br />
One of 500 digitiser cards <strong>for</strong> a Large<br />
Scale Science Project.<br />
Recent advances in FPGA’s have seen<br />
these devices evolve into programmable<br />
System On Chip (SOC) ASICs making<br />
these requirements feasible at reasonable<br />
cost and size. Typical FPGA components<br />
now contain multiple microprocessors,<br />
multiple multi-gigabit transceivers<br />
capable of driving common network<br />
standards, as well as multi million gates<br />
Figure 2:<br />
High per<strong>for</strong>mance <strong>Embedded</strong> DAQ <strong>for</strong><br />
Custom CMOS Sensor (not shown).<br />
Figure 3: Multiple Custom CMOS Pixel Sensor with high per<strong>for</strong>mance <strong>Embedded</strong> DAQ.<br />
<strong>ERCIM</strong> News No. 67, October 2006<br />
of programmable logic with DSP<br />
enhancements allowing per<strong>for</strong>mance<br />
rates up to 250 GMACS/s <strong>for</strong> the largest<br />
devices.<br />
This provides the opportunity <strong>for</strong><br />
shrinking our systems and producing<br />
embedded high per<strong>for</strong>mance DAQ with<br />
standard networked readout such as GBit<br />
Ethernet – Large Scale Science DAQ<br />
systems shrink wrapped into DAQ<br />
Sensor appliances.<br />
In CCLRC Technology we have demonstrated<br />
the technical feasibility of<br />
embedded hardware based on highspeed<br />
serial optical links, standard network<br />
protocols, and programmable<br />
System On Chip (SOC) FPGA devices<br />
to deliver across a wide range of requirements<br />
and projects.<br />
Our designs have implemented<br />
embedded hardware support features<br />
such as electronic fuses, supply monitoring,<br />
thermal monitoring, shutdown on<br />
fault, Wake On LAN type recovery from<br />
shutdown and low stand-by power.<br />
Remote reconfiguration of FPGA<br />
FLASH memory is possible together<br />
with encryption of the bit stream and<br />
automatic reversion to a fallback<br />
FLASH memory in the event of failure<br />
during re-programming. A typical small<br />
system might consist of a pixel sensor<br />
chip readout by an FPGA which is in<br />
turn readout by a PC server over a GBit<br />
Ethernet connection. A commodity<br />
SDRAM memory module connected to<br />
the FPGA provides data buffering and<br />
optical transceivers allow transmission<br />
of the GBit Ethernet over longer distances.<br />
Figure 3 shows an embedded DAQ<br />
module planned <strong>for</strong> use on SR applications<br />
reading out 16 CMOS Pixel image<br />
sensors capable of a multi KHz frame<br />
rate. The module can log up to 800<br />
MByte/s into SDRAM <strong>for</strong> a few seconds<br />
and then is readout to a PC server on two<br />
GBit Ethernet cables each sustaining 80<br />
MByte/s.