基于DO-178C机载设备通用外场加载软件设计

Field Loading Software for Airborne Equipment According to DO-178C

外场加载广泛应用于国内外各型号民用飞机的机载系统或设备,可显著地提升机载系统或设备的维护性。将适用的适航审定要求转换为具体设计策略是机载系统或设备加载软件设计的关键。DO-178C所列关于外场加载的系统安全性考虑构成了加载软件设计的基本审定和安全性要求。以满足DO-178C的安全性考虑为前提,针对TMS320F28335 DSP平台有限RAM和Flash存储资源,提出了一种基于ARINC825总线的机载设备通用外场软件设计策略。该设计策略全面考虑了数据传输协议鲁棒性、数据完整性校验、加载功能激活方式、软硬件兼容性检查、异常激活保护等多个方面安全设计措施,全面落实了适航审定对外场加载的安全性要求。某机载设备实践证明根据该策略实现的机载加载软件兼顾了数据传输速率和加载安全,有效提升了设备维护性。

The field-loading function is widely supported for the airborne systems or equipments of various aircrafts,which can significantly improve the maintainability of airborne equipments. The applicable certification consideration being completely converted into specific design strategies is essential for the design of the fieldloading software. The system safety considerations relating to field-loadable software( FLS) in DO-178 C forms the basic certification and safety requirements for the field-loading software design. A generic field-loading software design strategy for airborne equipments with limited memory resource based on ARINC825 is provided.Several key design strategies are described to ensure compliance with all DO-178 C FLS safety considerations,including the robust of data transmission protocol, data integrity verification, activation of field-loading function,software/hardware compatibility check,and inadvertent activation protection. It’s demonstrated in an airborne equipment project that both the data transmission speed and software loading safety are ensured,and the maintainability of the equipment is effectively improved.