sing embedded instruments to design weblabs
TRANSCRIPT
USING EMBEDDED INSTRUMENTS
TO DESIGN WEBLABS AN FPGA-EMBEDDED OSCILLOSCOPE BASED ON THE IEEE1451.0 STD.
ISEP/CIETI / LABORIS
Ricardo Costa ([email protected])
Diogo Eloi Pinho ([email protected])
Gustavo R. Alves ([email protected] )
exp.at’15 - Online Experimentation conference
Ponta Delgada, São Miguel Island, Azores, Portugal
2 – 4, June 2015
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INDEX
1. Introduction
2. Embedded instruments in weblabs
3. Using FPGAs and the IEEE1451.0 for
designing embedded instruments
4. An embedded digital oscilloscope
5. Conclusions and perspectives
3/13
1- INTRODUCTION
Instruments in Electrical
Engineering laboratories
Analogue
Modular
Stand-alone
Digital
Weblabs can also adopt embedded
instruments
Embedded
4/13
2- EMBEDDED INSTRUMENTS IN WEBLABS
Embedded instruments may access the experiments
according to three architectures:
System-on-Chip (SoC),
integrates the instruments and
the experiments within the
same chip.
Board,
integrates the instruments
within chips bound to the
experiments located in the same
board.
External,
the board with chips
accommodates the embedded
instruments bound to
external experiments.
5/13
3- USING FPGAS AND THE IEEE1451.0 FOR
DESIGNING EMBEDDED INSTRUMENTS
• FPGAs are reconfigurable devices that use standard Hardware Description
Languages (HDLs – Verilog or VHDL) to design hardware blocks able to run
in parallel (these can be embedded instruments);
• FPGAs may embed more than one instrument in the same core (useful for weblabs!).
Despite Verilog and VHDL are standard HDLs they do not describe
the way to access (or design) a particular module (instrument).
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3- USING FPGAS AND THE IEEE1451.0 FOR
DESIGNING EMBEDDED INSTRUMENTS • The IEEE1451.0 Std. (2007) is the suggested solution for the standard access and
design of embedded instruments;
• Created to network-interface transducers (sensors and actuators), defines a set of
APIs and operating modes supported by specifications provided by
Transducer Electronic Data Sheets (TEDSs);
• Defines an architecture based on two modules (TIM and NCAP);
TEDS structure
Reference
model
7/13
3- USING FPGAS AND THE IEEE1451.0 FOR
DESIGNING EMBEDDED INSTRUMENTS
ADC /
DAC
Ethernet
interface
Buttons
LCD
display
JTAG
interface
Digital I/0
pins
Physical
interfaces
(RS232)FPGA
LED
indicators
DRAM
memory
E2PROM
memory
Buttons
FPGA-based board to
implement a digital
oscilloscope (embedded
instrument)
Block diagram of a
digital oscilloscope
8/13
3- USING FPGAS AND THE IEEE1451.0 FOR
DESIGNING EMBEDDED INSTRUMENTS
NCAP TIM
TEDS
commandsAPIs
TCs
Web
IEEE1451.x
TEDS (Transducer Electronic Data Sheet)
comprises data divided in Type Length Value
(TLV fields) to indicate specific features and
the current operation of a particular TC
(Transducer Channel) Provides different IEEE1451.0 commands
(e.g. WriteTEDS; ReadTEDS, etc.)
9/13
4- AN EMBEDDED DIGITAL OSCILLOSCOPE
FPGA-based board
(several blocks described in
Verilog HDL)
Computer Interface (JAVA)
Note: currently it is locally accessed, but a
web interface can be designed to access the
instrument according to the IEEE1451.0 Std.
Time/Division
Triggering
DC
Level: 0.00
AC
Coupling
Slope
Up
Down
Oscilloscope
Command editor
replies
command to send
command replies
Digital oscilloscope
Send
IEEE1451.0 commands:
(TCoperate, TCidle, ReadTEDS, WriteTEDS)
10/13
4- AN EMBEDDED DIGITAL OSCILLOSCOPE
TEDS defines: oscilloscope as a sensor;
units (volts); amplitudes (0.4 V to 2.9 V);
resolution (0.15 mV defined according to
the ADC); number of samples (2500);
trigger level and slope; immediate mode to
transmit samples to the computer
interface; and scale definitions for
representation in the computer interface.
TC ID(2 octets)
Class(1 octet)
Function(1 octet)
Length(2 octets)
data(variable num. octets)
MSB lsb
Success / failflag (2 octets)
Length(2 octets)
data(variable num. octets)
command
reply
MSB lsb
IEEE1451.0 commands
TCoperate:
turns ON the oscilloscope;
TCidle:
turns OFF the oscilloscope;
TEDS Read/Write:
to access the TEDS’s fields.
11/13
4- AN EMBEDDED DIGITAL OSCILLOSCOPE Changing a specific button means sending an
IEEE1451.0 command to change the TEDS’s
fields (WriteTEDS / ReadTEDS).
Commands are sent to the
TIM using the
hexadecimal format and
the replies retrieved in
the same format.
Turns ON/OFF
(TCoperate /TCidle)
2500 samples
presented
12/13
5- CONCLUSIONS AND PERSPECTIVES
• Digital stand-alone or modular instruments can be replaced by
embedded instruments to implement a weblab
(more flexibility and a reduction of costs in their design);
• Reconfigurable devices, in particular FPGA-based boards, can be the
adopted infrastructures for implementing embedded
instruments;
• Describing the instruments in HDL (e.g. VHDL or Verilog) promotes
their share and the use of different FPGAs to implement the
weblab infrastructure;
• The IEEE1451.0 Std. (commands and TEDSs) is an interesting
solution to standardize the design and the access to embedded
instruments;
• The implemented solution alerted for the possibility of using in
weblabs embedded instruments (reconfigurable in FPGAs),
designed and accessed according to the IEEE1451.0 Std.
• In the future, other devices, such as FPAAs, should be
evaluated to implement embedded instruments!
14/13
TEEM 2015
CALL FOR PAPERS 7-9 OCTOBER 2015, PORTO, PORTUGAL
HTTP://TEEMCONFERENCE.EU
Important dates: NEW Paper Submission deadline: June 14
Notification of acceptance: July 12
Camera-ready version: July 21
Authors’ registration deadline: July 26
All accepted papers will be included in the
conference proceedings, which will be
published in the ACM Digital Library as a
volume in its International Conference
Proceedings Series with ISBN