jose manuel pérez lobato eva martín lobo
DESCRIPTION
OMC - INTEGRAL Memory Management. Jose Manuel Pérez Lobato Eva Martín Lobo. INTEGRAL I nternational G amma- R ay A strophysics L aboratory. Spacecraft Description : International mission with the participation of all 14 member states of ESA . - PowerPoint PPT PresentationTRANSCRIPT
INTA
Jose Manuel Pérez LobatoEva Martín Lobo
OMC - INTEGRAL
Memory Management
OMC-INTEGRAL Memory Management ADA Europe 2002
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INTEGRAL International Gamma-Ray Astrophysics
Laboratory• Spacecraft Description : International
mission with the participation of all 14
member states of ESA .• Objective: Gather the most energetic
radiation that comes from space (Gamma- ray).
• Date of launch: October 2002.
• Launcher:A Russian Proton rocket will place the spacecraft into orbit.
• Time of use : 2 years ( Possible extension for up to 5 years)
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INTEGRAL INSTRUMENTS
• The SPECTROMETER (SPI) • The IMAGER (IBIS )
• The two X-RAY MONITOR
(JEM-X)
• The OPTICAL MONITORING CAMERA
( OMC)
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INTEGRAL INSTRUMENTS
• The SPECTROMETER (SPI)
– Will perform spectral analysis of gamma-ray point sources and extended regions over an energy range between 20 keV and 8 MeV.
• The Imager on Board the INTEGRAL Satellite (IBIS )
– Will give sharper gamma-ray images than any previous instrument, it will achieve a high angular resolution of 12 arcmin over an energy range between 15 keV and 10 MeV.
• The Joint European X-Ray Monitor (JEM-X)– will make observations simultaneously with the
main gamma-ray instruments and will provide images in the energy range of 3 - 35 keV.
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OMCOptical Monitoring Camera
• OMC offers the first opportunity to make long observations of the visible light coming from the gamma-ray and X-ray sources.
• OMC is a CCD detector of 1024x 1024 pixels located in the top of the satellite.
• It is sensitive to stars with a
visual magnitude up to 19.7
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OMC Modes• Normal Mode :
– Some windows to centre the image– Small windows of stellar objects.
• Trigger Mode :– One big window for sporadic events
(supernova explosion, stellar black hole)
• Calibration Modes
– Flat Field Calibration:• Extraction of large sections from the CCD
in order to calibrate the CCD and detect damaged pixels.
– Dark Current Calibration:
• Extraction of sections on the left and right borders of the visible imaging area.
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OMC
OMC Components
OMCAS
FEE
Camera Unit
CSSW
DPE HW
Ground System
Spacecraft
SPI IBIS JEM-X
OBDH
•DPE:1750 MicroprocessorMMU : Memory Management Unit
•CSSW : Common Service SoftWare (Ada 83)
•OMCAS : OMC Application Software (Ada 83)
•ASTRES: Operating System
•FEE: Front-End Electronics
•DPE-FEE Interface:•RS-422 serial lines (HSL,LSL)•Bi-level, ON/OFF commands•TM (Analogue channels)
•OBDH: OMC <->Spacecraft Communication Module
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OMCAS(OMC Aplication Software)
• Software Tasks• Collect TC : It is in charge of collecting and validating the incoming
commands performing the syntax and sequence analysis
1CollectTC
2ControlOMC
3Generate
TM
4PerformPHK
tc
validtc
rawtm
mode
sc
tc_info
hk_tm
hk pm_cmd
tm
roe_cmd
control_omc_tm
ccd_tm
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OMCAS(OMC Aplication Software)
• Software Tasks• Control OMC : It is responsible for performing mode changes and all
the related mode activities
1CollectTC
2ControlOMC
3Generate
TM
4PerformPHK
tc
validtc
rawtm
mode
sc
tc_info
hk_tm
hk pm_cmd
tm
roe_cmd
control_omc_tm
ccd_tm
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OMCAS(OMC Aplication Software)
• Software Tasks• Generate TM: It will pack the OMC telemetry provided by the
different data transformations and will send it to the OBDH.
1CollectTC
2ControlOMC
3Generate
TM
4PerformPHK
tc
validtc
rawtm
mode
sc
tc_info
hk_tm
hk pm_cmd
tm
roe_cmd
control_omc_tm
ccd_tm
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OMCAS(OMC Aplication Software)
• Software Tasks• Perform PHK: It is in charge of executing the tasks related to the
periodic monitor (HouseKeeping Telemetry). The information is acquired once each TM cycle (8 sec.) and included in the TM packet
1CollectTC
2ControlOMC
3Generate
TM
4PerformPHK
tc
validtc
rawtm
mode
sc
tc_info
hk_tm
hk pm_cmd
tm
roe_cmd
control_omc_tm
ccd_tm
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1750 Address Space
PhysicalMemory
64 Kwords
256
Pages
LogicalPage=4Kwords
Extended MemorySystem
16 AS
AddressState(AS)
64 Kwords
16 pages
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Memory:Architectural Restrictions
Total Memory1 Mword(1 word= 2bytes)
16 data AS 16 SW code AS
16 Logical Pages
16 Logical Pages
1 Logical Page (4 Kwords)
1 Logical Page (4 Kwords)
1 Physical Page (4 Kwords)
1 Physical Page (4 Kwords)
Task Task
Static Association
Memory available per task: 64Kwords
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.
16-BIT LOGICAL ADDRESS
INSTRUCTION /OPERAND ACCESS DESIGNATOR FROM HARDWARE
LOGICAL ADDRESS OF 4K PAGE
AL E WP P A
EW P P A
PS AS
PROCESSOR STATUS WORD
4
5
4
8
LOCK & KEY ACCESS PROTECT WRITE PROTECT
(OPERAND ACCESS)4
20-BIT PHYSICAL ADDRESS
LPA
124
A L
ADDRESS OF WORD WITHIN 4K
AS
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Low level memory management– SW requirements:
• To share data between AS (tasks ) • Reuse code Store code in a physical page to be used by several tasks
– Problem • There are 256 logical pages and 256 physical pages• If 2 logical pages are associated to 1 physical page, 1 physical page will not be accessible.
Logical Pages Physical Pages
Not accessible Page
Accessible Pages
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Physical page 1
Low level memory management
– The solution implies to change the values of the MMU registers
• It should be programmed in assembler.• The data structure defined in ADA is the “filter” to
access to the physical memory. Changing the association implies that a single register is used to access to several parts of the memory.
• Solution– Change, in a dynamic way, the Logical to Physical page
association.
Logical pagetype t_window is
array (1..1024) of t_unsigned16
Physical page 2
Physical page 3
Logical pagetype t_window is
array (1..1024) of t_unsigned16
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CCDCharge Copled Device
• Structure:– Visible area: 1024x1024 visible pixels + several non visible lines– Hide area : storage area ,same size visible area,
• Working algorithm:– Image exposure for a TC time– Transmit the Visible Area -->> Hide Area– Digitalize the individual pixels values and transmit them to the memory
processor
• Restriction:– Images can not be more than10 seconds at the Hide Area
1 pixel =16 bits (12 useful)
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A/DA/D
VisibleArea
HidenArea
CCD Graphic Diagram
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OMC Working modes• Normal Mode :
– 10 windows of 31x31 pixels to centre the image– 400 windows of variable size from 5x5 to 11x11 pixels
each one
• Trigger Mode :– 1 window of 100x100 pixels.
• Calibration modes : – High size window =>
• Use all the available memory and • Change the Logical---Physical page association
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Window extraction1.- Order windows by its position in the CCD
2.- Extract 8 lines from the CCD ( 8 x1024 words = 2 pages)
3.-Get the pixels of each window, discarding the 4 non useful bits of each pixel
4.-Transfer the windows to the TM memory pages marking them as empty, half-full or full
5.-Construct TM packets
TM task and Science Task share physical pages
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Normal Mode
RAM DPE
SCIENCE TASKAddress State
Logical Pages
TELEMETRY TASK Address StateLogical Pages
Physical Pages
1
2
3
10
80
2
1
3
4
1 2 3 4
5 640
1 2 3 4
5 6
40
41
HSSL
CCD STORAGE AREA
1 25
3
679
41
ROE FIFO
8 rows
4
8
3940
10
80
1 2 3 4
5 6
40
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FF Calibration Mode
CCD STORAGE AREA
ROE FIFO
RAM DPE
FFCAL TASKAddress State
1
2 Logical Page
TELEMETRY TASK Address State
Physical Pages
4K bytes
HSSL
2
1
3
Logical Pages
Full
FullFree
Free
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Conclusions
• Solution approved by ESA engineers and included in the CSSW module in order to all instruments could use it.
• In Embedded Systems low level restrictions define high level design solutions.
• Experience acquired will be reused in future projects (Eddington).