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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 .

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Jose manuel p rez lobato eva mart n lobo

OMC - INTEGRAL

Memory Management

Jose Manuel Pérez Lobato

Eva Martín Lobo


Integral i nternational g amma r ay a strophysics l aboratory

INTEGRALInternationalGamma-RayAstrophysicsLaboratory

  • 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)

OMC-INTEGRAL Memory Management ADA Europe 2002


Integral instruments

INTEGRAL INSTRUMENTS

  • The SPECTROMETER (SPI)

  • The IMAGER (IBIS )

  • The two X-RAY MONITOR (JEM-X)

  • The OPTICAL MONITORING CAMERA

    ( OMC)

OMC-INTEGRAL Memory Management ADA Europe 2002


Integral instruments1

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.

OMC-INTEGRAL Memory Management ADA Europe 2002


Omc o ptical m onitoring c amera

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

OMC-INTEGRAL Memory Management ADA Europe 2002


Omc modes

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.

OMC-INTEGRAL Memory Management ADA Europe 2002


Omc components

OMC

OMCAS

FEE

DPE HW

Camera

Unit

OBDH

Spacecraft

Ground

System

SPI

IBIS

JEM-X

OMC Components

  • DPE:

    • 1750 Microprocessor

    • MMU : Memory Management Unit

  • ASTRES: Operating System

  • CSSW : Common Service SoftWare

  • (Ada 83)

CSSW

  • OMCAS : OMC Application Software

  • (Ada 83)

  • 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

OMC-INTEGRAL Memory Management ADA Europe 2002


Omcas o mc a plication s oftware

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

OMC-INTEGRAL Memory Management ADA Europe 2002


Omcas o mc a plication s oftware1

OMCAS(OMC Aplication Software)

  • Software Tasks

  • Control OMC : It is responsible for performing mode changes and all the related mode activities

OMC-INTEGRAL Memory Management ADA Europe 2002


Omcas o mc a plication s oftware2

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.

OMC-INTEGRAL Memory Management ADA Europe 2002


Omcas o mc a plication s oftware3

OMCAS(OMC Aplication Software)

  • Software Tasks

  • Perform PHK:It is in charge ofexecuting 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

OMC-INTEGRAL Memory Management ADA Europe 2002


1750 address space

Extended Memory

System

Physical

Memory

64

Kwords

256

Pages

Address

State

(AS)

64 Kwords

16

AS

16

pages

Logical

Page=

4Kwords

1750 Address Space

OMC-INTEGRAL Memory Management ADA Europe 2002


Memory architectural restrictions

Static Association

Memory:Architectural Restrictions

Total Memory

1 Mword

(1 word= 2bytes)

Task

16 data AS

16 SW code AS

Task

16 Logical Pages

16 Logical Pages

1 Physical Page (4 Kwords)

1 Logical Page (4 Kwords)

1 Logical Page (4 Kwords)

1 Physical Page (4 Kwords)

Memory available per task: 64Kwords

OMC-INTEGRAL Memory Management ADA Europe 2002


Jose manuel p rez lobato eva mart n lobo

20-BIT PHYSICAL ADDRESS

LOCK & KEY ACCESS PROTECT

WRITE PROTECT (OPERAND ACCESS)

4

8

AL

P P A

E W

P P A

A L

EW

12

4

5

LPA

4

AS

PS

AS

4

PROCESSOR STATUS WORD

.

16-BIT LOGICAL ADDRESS

LOGICAL ADDRESS OF 4K PAGE

ADDRESS OF WORD WITHIN 4K

INSTRUCTION /OPERAND ACCESS DESIGNATOR FROM HARDWARE

OMC-INTEGRAL Memory Management ADA Europe 2002


Low level memory management

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

Accessible Pages

Not accessible

Page

OMC-INTEGRAL Memory Management ADA Europe 2002


Low level memory management1

Low level memory management

  • Solution

    • Change, in a dynamic way, the Logical to Physical page association.

Physical page 1

  • 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.

Logical page

type t_window is

array (1..1024) of t_unsigned16

Physical page 2

Logical page

type t_window is

array (1..1024) of t_unsigned16

Physical page 3

OMC-INTEGRAL Memory Management ADA Europe 2002


Ccd c harge c opled d evice

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)

OMC-INTEGRAL Memory Management ADA Europe 2002


Jose manuel p rez lobato eva mart n lobo

Visible

Area

Hiden

Area

CCD Graphic Diagram

A/D

A/D

OMC-INTEGRAL Memory Management ADA Europe 2002


Omc working modes

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

OMC-INTEGRAL Memory Management ADA Europe 2002


Window extraction

Window extraction

1.- 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

OMC-INTEGRAL Memory Management ADA Europe 2002


Normal mode

CCD STORAGE AREA

RAM DPE

Physical Pages

TELEMETRY TASK Address State

Logical Pages

SCIENCE TASK

Address State

1

80

1

2

3

4

Logical

Pages

1

1

40

41

39

5

6

40

2

2

1

2

3

4

41

80

10

1

2

3

4

8

9

7

5

6

3

6

3

40

5

4

5

6

2

3

40

8 rows

HSSL

4

10

ROE FIFO

Normal Mode

OMC-INTEGRAL Memory Management ADA Europe 2002


Ff calibration mode

Full

Full

RAM DPE

Free

Physical

Pages

FFCAL TASK

Address State

TELEMETRY TASK

Address State

CCD STORAGE AREA

Free

Logical Pages

1

1

2

Logical Page

4K bytes

2

HSSL

3

ROE FIFO

FF Calibration Mode

OMC-INTEGRAL Memory Management ADA Europe 2002


Conclusions

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).

OMC-INTEGRAL Memory Management ADA Europe 2002


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