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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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slide1

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

slide14

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

slide18

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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