1. SOIS EDS ESA Internal Study YGT Program
F. Torelli & P. Skrzypek CCSDS Fall Meeting /10/2012

2. Introduction Outline Overview of the SOIS EDS study
Recap on basic SOIS concepts
Points currently under investigation
Driver/device behavioural model in SOIS EDS
Algorithms representation in SOIS EDS
Objectives:
Overview of the SOIS EDS Study
Basic SOIS EDS concepts
Points of discussion regarding:
Device behavioural model
Behavioural model representation in EDS

3. Overview of the SOIS EDS study

4. SOIS EDS study Young Graduate Trainee:
MSc in Informatics, spec. Computer Engineering
Experience in OS porting, drivers development, sensors wireless networks development and testing
1 year, full time
Objectives:
SOIS EDS technology and schema assessment.
EagleEye AOCS ICDs translation into SOIS EDS.
DVS and DAS auto-coding and integration into EagleEye Central SW
EagleEye AOCS performance verification

5. EagleEye and Avionics Test Bench
SOIS EDS from AOCS equipment
SOIS DAS & DVS into Central SW

6. Recap on basic SOIS concepts

7. SOIS Command & Data Acquisition Service Primitives
Application
ACQUIRE_FROM_DEVICE.request (DASAP Address, Transaction Identifier, Device Identifier, Value Identifier)
ACQUIRE_FROM_DEVICE.indication (DASAP Address, Transaction Identifier, Value, Result Metadata,
Timestamp (optional))
COMMAND_DEVICE.request (DASAP Address, Transaction Identifier, Device Identifier, Value Identifier, Value)
COMMAND_DEVICE.indication (DASAP Address, Transaction Identifier, Result Metadata)
DVS
Service Primitives
Device Abstraction Control Procedure
ACQUIRE_FROM_DEVICE.request (Transaction Identifier, Virtual Device Identifier, Value Identifier)
ACQUIRE_FROM_DEVICE.indication (Transaction Identifier, Value, Result Metadata, Timestamp (optional))
COMMAND_DEVICE.request (Transaction Identifier, Virtual Device Identifier, Value Identifier, Value)
COMMAND_DEVICE.indication (Transaction Identifier, Result Metadata)
DAS
Service Primitives
Device-specific
Access Protocol
PACKET_SEND.request (PSSAP Address, PDSAP Address, Service Class, Priority, Channel, Data)
PACKET_RECEIVE.indication (PSSAP Address, PDSAP Address, Service Class, Channel, Data)
PACKET_FAILURE.indication (PSSAP Address, PDSAP Address, Failure Metadata)
READ.request (MASAP Address, Destination Address, Transaction ID, Memory ID, Start Memory Address, Size, Priority, Channel,
Authorisation (optional))
READ.indication (MASAP Address, Destination Address, Transaction ID, Memory ID, Start Memory Address, Size, Priority,
Channel, Data, Result Metadata)
WRITE.request (MASAP Address, Destination Address, Transaction ID, Memory ID, Start Memory Address, Size, Priority, Channel,
Data, Acknowledge (optional), Authorisation (optional), Verification (optional))
READ/MODIFY/WRITE.request (MASAP Address, Destination Address, Transaction ID, Memory ID, Memory Address, Size,
Mask, Priority, Channel, Data, Acknowledge (optional), Authentication (optional), Verification (optional))
MEMORY_ACCESS_RESULT.indication (MASAP Address, Destination Address, Transaction ID, Memory ID,
Start Memory Address, Size, Result Metadata)
SubNet
PS & MAS Service Primitives
ECSS Protocol
Datalink

8. SOIS Command & Data Acquisition Procedures & Protocols
Application
DVS
Service Primitives
Device Abstraction Control Procedure
Non-Standard Procedure, it depends on the device/equipment
DAS
Service Primitives
Device-specific
Access Protocol
Non-Standard Protocol, it depends on the device/equipment
SubNet
PS & MAS Service Primitives
ECSS Protocol
Datalink
MilBus 1553 communication protocol service primitives and engine [ECSS-E-ST-50-13C]
Spacewire RMAP service primitives and engine [ECSS-E-ST-50-52C]
Others…

9. SOIS Command & Data Acquisition Electronic Data Sheets
Application
SOIS DoT
Terms
DVS
Service Primitives
Device Abstraction Control Procedure
Service Primitives Semantics
SOIS EDS
Code Generation
Service capability
DAS
Service Primitives
Device-specific
Access Protocol
Information to generate DACP
Code Generation
Mapping between DACP and DAS Primitives
SubNet
PS & MAS Service Primitives
ECSS Protocol
Datalink
Information to generate DAP
No need for ECSS protocol description in the SOIS EDS
Mapping between DSAP and SubNet Primitives

10. Points currently under investigation

11. Behavioural Model Options
A. Driver behaviour
EDS includes the DACP and DAP algorithms
DVS and DAS SW is the translation of the EDS algorithms
B. Device behaviour
EDS includes manufacturer behaviour state chart
Code generator produces the DVS and DAS SW
SOIS EDS
#define HPC_STATUS_FIRE_MASK 2
#define PM_ID_REDUNDANT_MASK 0x
#define PM_ID_NOMINAL_MASK 0x
#define GPI_DATA_REG_ADDR 0x01F800AC
typedef UNSIGNEDINT8 HPC_REGS_ACCESS[(sizeof(struct HPC_REGS) / sizeof(MEMADDR))];
/* TSC695F GPI (GENERAL PURPOSE INTERFACE) PORT */
struct HPC_REGS rHPCRegs;
/* Local module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_PAR = ACARO_CH2;
/* Partner module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_LOC = ACARO_CH1;
*ArmFlag = ((TempPattern
Service capability
#define HPC_STATUS_FIRE_MASK 2
#define PM_ID_REDUNDANT_MASK 0x
#define PM_ID_NOMINAL_MASK 0x
#define GPI_DATA_REG_ADDR 0x01F800AC
typedef UNSIGNEDINT8 HPC_REGS_ACCESS[(sizeof(struct HPC_REGS) / sizeof(MEMADDR))];
/* TSC695F GPI (GENERAL PURPOSE INTERFACE) PORT */
struct HPC_REGS rHPCRegs;
/* Local module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_PAR = ACARO_CH2;
/* Partner module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_LOC = ACARO_CH1;
*ArmFlag = ((TempPattern
Information to generate DACP
Mapping between DACP and DAS Primitives
#define HPC_STATUS_FIRE_MASK 2
#define PM_ID_REDUNDANT_MASK 0x
#define PM_ID_NOMINAL_MASK 0x
#define GPI_DATA_REG_ADDR 0x01F800AC
typedef UNSIGNEDINT8 HPC_REGS_ACCESS[(sizeof(struct HPC_REGS) / sizeof(MEMADDR))];
/* TSC695F GPI (GENERAL PURPOSE INTERFACE) PORT */
struct HPC_REGS rHPCRegs;
/* Local module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_PAR = ACARO_CH2;
/* Partner module channel Id. (constant).*/
const UNSIGNEDINT32 HPC_LOC = ACARO_CH1;
*ArmFlag = ((TempPattern
Information to generate DAP
Mapping between DSAP and SubNet Primitives

12. Behavioural Model Trade-Off
A. Driver behaviour
“Easy” DVS and DAS SW code generation/translation
Solution in-line with today’s philosophy of drivers’ development
DACP and DAP algorithms in EDS are good for DVS and DAS simulation
EDS might capture a simplified behaviour of the device
EDS to be produced by the device user
DACP and DAP algorithms in EDS are coded manually
B. Device behaviour
“Difficult” DVS and DAS SW code generation
Manufacturers have to comply to standard rules to describe the device behaviour description/statechart
EDS’ device behaviour is good to simulate the device
EDS captures the complete behaviour of the device
EDS’ device behaviour is provided by the manufacturer
DVS and DAS SW code is automatically generated

13. Algorithms Representation Limitations
SCXML & MathML  Baseline, but…
Mathematical expressions are not sufficient to represent algorithms including, for example, bitwise operations, checksums, switch cases…
State machines are good for the description of macroscopic behaviour or asynchronous events, but not for simple elaborations such as loops or access to arrays.
Example from NPAL camera:
NPAL_DEFLIST raw data at DAS interface
DEFECTIVE_PIXELS_LIST at DVS interface:
Each pixel is described by:
(uint32 x, uint32 y, uint8 type)
Where:
pixels (x, y) coordinates are counted from top left, starting with 0
type can be:
hot_pixel 0
cold_pixel  1
unknown  2
Bits (little endian)
Value
0  cold pixel
1  hot pixel
1-3
Not used
4-13
Pixel column
14-23
Pixel row
for(i=0; i<array_size(NPAL_DEFLIST); i++) {
DEFECTIVE_PIXELS_LIST[i].type = NPAL_DEFLIST[i] & 0x ? 0:1;
DEFECTIVE_PIXELS_LIST[i].x = (NPAL_DEFLIST[i] >> 10) & 0x3FF;
DEFECTIVE_PIXELS_LIST[i].y = NPAL_DEFLIST[i] & 0x3FF; }

14. Algorithms Representation Improvements
To incorporate programming language code inside the states of the state machines
To complement SCXML and MathML with other formalisms, for example ASN.1 for interface definition and bit fields mapping
Additional Needs
Availability of parser/code generators
Rules and conventions in the way algorithms are hooked to the services
SOIS EDS Schema should include the framework for DACP and DAP algorithms definition

15. Conclusions Objectives Overview of the SOIS EDS study
1 man/year, prototyping of SOIS EDS in Avionics Test Bench
Recap on basic SOIS EDS concepts
DVS/DAS/SubNet (services), DACP (procedures), DAP (protocols).
Points currently under investigation
Trade-off between driver and device behavioural model in SOIS EDS
Need for the definition of a framework for the algorithms representation in SOIS EDS