	Document Name: Effective Date: soon Revision: draft Title:

REVISION HISTORY

Rev	Date	Description	Author/Approval

Table of Contents

1 Introduction	4

1.1 Purpose	4

1.2 Scope	4

1.3 General Description	4

1.4 Project Acronyms and Abbreviations	5

1.5 Applicable Documents	8

1.5.1 External Documents	8

1.5.2 Internal Documents	9

2 Software Overview	10

2.1 Allocation of Requirements	10

2.2 Software Architecture	11

2.3 Software Inputs and Outputs	11

2.4 Software Data and Control Flow	11

2.5 Software Resource Limitations	11

2.6 Scheduling and Inter-Processor Communications	11

2.7 Design Methods and Implementation Detail	11

2.8 Partitioning Methods	11

2.9 Previously Developed Software Components	11

2.10 Derived Requirements	12

2.11 Deactivated Code	12

2.12 Traceability of Safety Rational	12

3 SOFTWARE MODULE DESCRIPTION	13

3.1 Hardware Support Layer	13

3.1.1 StartupSafety.c - Startup code and primary interrupt vector table	13

3.1.2 ClockController.c – Entry point to Application	13

3.1.3 FlashMemoryController.c – Entry point to Application	14

3.1.4 WDTController.c – Entry point to Application	14

3.2 Application Layer	14

3.2.1 mainLoop.c – Entry point to Application	14

3.2.2 FuelFlowController.c – Fuel Flow input reader/converter/calibrator	14

3.2.3 Airdata calculation modules	14

3.2.3.1AirData – Barometric	14

3.2.3.2BaroSetController – Barometric	14

3.2.3.3OutsideAirTemperature – OAT calibration and conversion	14

3.2.3.4TrueAirTemperature – TAT calibration and conversion	15

3.2.4 Navigation data calculation modules	15

3.2.4.1NavData – Navigation Data	15

3.2.4.2WindComputer – Wind direction ans speed	15

3.2.5 Serial I/O Interfaces	15

3.2.5.1SerialtoParallelController.c – Serial COM-A & B I/O Interface	15

3.2.5.2UartController.c – Serial COM-A & B Output Interface	15

3.2.5.3XilinxUartController.c – Serial COM-C & D Output Interface	15

3.2.5.4ARINC429Controller.c – ARINC 429 Controller	15

3.2.5.5GpsDataParser.c – Serial Input Decoder	15

3.2.5.6GarminMessageSerializer.c – Serial Output Encoder	16

3.2.5.7KingDFormatter.c – Serial Output Encoder	16

3.2.5.8AltitudeDataFormatter.c – Serial Output Encoder	16

3.2.6 Synchro Input Modules	16

3.2.6.1SynchroCalculator.c – Heading Synchro Input Reader	16

3.2.6.2SynchroPeakDetector.c – Heading Synchro Input driver	16

3.2.7 Pressure ADC Input Modules	16

3.2.7.1A2DController.c – Pressure Sensor Input Controller	16

3.2.7.2AirSpeedComputer.c – Compute Airspeed from input Pitot and Static Pressure	16

3.2.7.3AltitudeComputer.c – Compute Pressure Altitude from input Static Pressure	16

3.2.7.4PressureSensorController.c – Pressure Sensor Controller	16

3.2.8 Sandia AIM Modules	16

3.2.8.1AltitudeInflightMonitor.c – AIM monitor	17

3.2.8.2SwitchPressMonitor.c – AIM Switch Press Monitor	17

3.2.9 Ground Based Modules	17

3.2.9.1TestDataOutput.c – Production Test Data Output module	17

3.2.9.2AirDataSetup.c – Unit Configuration module	17

3.2.10 Utility Modules	17

3.2.10.1Task.c – Task scheduler module	17

3.2.10.2math.c – Reentrant C Library Utilities	17

3.2.10.3MSP430.h – System Definitions	17

3.3 Project Support Files	18

3.3.1 Makefile – Project Make File	18

3.3.2 ProjLink.Cmd – Project Linker Command File	18

4 LOW-LEVEL SOFTWARE REQUIREMENTS	19

5 REQUIREMENTS TRACEABILITY MATRIX	20

5.1 Requirements To Code	20

5.2 Code To Requirements	20

Introduction

Project Acronyms and Abbreviations

Applicable Documents

The following documents are listed for reference only. Each document is applicable to these requirements only to the extent specified herein.

External Documents

Internal Documents

Software Overview

The software will be structured as a simple time/event-triggered with a statical priority scheduler handling background (translation) tasks. First the program will runs through a startup and initialization section. This will be run once at startup and performs memory allocation, hardware initialization and task initialization.

Allocation of Requirements

LOW-LEVEL SOFTWARE REQUIREMENTS

This section lists the low-level software requirements. Each requirement is identified by a unique number associated with a high-level software requirement.

REQUIREMENTS TRACEABILITY MATRIX

The following table lists the trace of all high level software requirements and the system level requirement which they trace to. The following system requirements are not present in this software trace matrix for the listed reasons.

System requirements not traceable to software:

Allocated to hardware: 2, 7, 13, 19, 20, 27, 30, 32, 45, 47, 50, 52, 53

Canceled requirement: 17, 38 and 39

Allocated to hardware testing 33, 44, 46, 54, 55, 56, 57

Regulatory options not applicable to this product: 28, 31 and 34

Requirements To Code

The following table lists system requirements traced to Software High-Level requirements traced to software low level requirements traced to the source code which implements them. This table is generated from the RTMS Requirements-Traceability-Management-System but the data is verified and controlled here. This data is generated and verified in support of the following DO-178B objectives:

A-4 (1) Low-level requirements comply with high-level requirements

A-4 (6) Low-level requirements are traceable to high-level requirements

A-5 (1) Source Code complies with low-level requirements

A-5 (5) Source Code is traceable to low-level requirements

The trace matrix data review along with the code reviews which utilize the trace data ensure that these objectives are achieved.

Code To Requirements

The following table lists the source code files implementing low-level software requirements traced to high-level software requirement, traced to system requirements. This table is generated from the RTMS Requirements-Traceability-Management-System but the data is verified and controlled here. This data is generated and verified in support of the following DO-178B objectives:

A-4 (1) Low-level requirements comply with high-level requirements

A-4 (6) Low-level requirements are traceable to high-level requirements

A-5 (1) Source Code complies with low-level requirements

A-5 (5) Source Code is traceable to low-level requirements

The trace matrix data review along with the code reviews which utilize the trace data ensure that these objectives are achieved.

Sandia Aerospace – Confidential – Do not Duplicate or Distribute	Page 12 of 12

Software Design Description - SADC 7-35, Fuel Airdata Computer

Karl Lieder

2007-07-27T08:58:44