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The ARINC 429 Data, Format 0 packets are used to record data messages from an ARINC 429 data bus. ARINC 429 is a unidirectional data bus that is commonly found on commercial and transport aircraft. Words are 32 bits in length and most messages consist of a single data word. Messages are transmitted at either 12.5 or 100 kbit/s from a transmitting system to one or more receiving systems. The transmitter is always transmitting either 32-bit data words or the NULL state. An ARINC data packet can contain multiple messages.

The layout of the CSDW is shown in Figure 6-36. The uMsgCount field indicates the number of recorded ARINC 429 messages.

struct SuArinc429F0_ChanSpec 
    { 
    uint32_t    uMsgCount   : 16;   // Message count 
    uint32_t    Reserved    : 16;   // 
    } 

Individual ARINC 429 data messages follow the CSDW. Each message is preceded with an intra-packet data header followed by the ARINC 429 data word.

The layout of the ARINC 429 data message intra-packet data header is shown in Figure 6-37. The uGapTime field is the time between the beginning of the preceding bus word and the beginning of the current bus word in 0.1 microsecond increments. The uBusSpeed field indicates the bit rate of the recorded bus message. The bParityError flag indicates the presence of a parity data error. The bFormatError flag indicates the presence of one of several types of data format errors. The uBusNum field identifies the specific ARINC 429 bus associates with the recorded data message.

struct SuArinc429F0_Header 
    { 
    uint32_t    uGapTime        : 20;   // Gap Time 
    uint32_t    Reserved        :  1;   // 
    uint32_t    uBusSpeed       :  1;   // Bus Speed 
    uint32_t    bParityError    :  1;   // Parity Error 
    uint32_t    bFormatError    :  1;   // Data type 
    uint32_t    uBusNum         :  8;   // Bus number 
    } 

The layout of the individual ARINC 429 data work is shown in Figure 6-38. Refer to the ARINC 429 standard for the interpretation of the specific data fields.

struct SuArinc429F0_Data 
    { 
    uint32_t    uLabel      :  8;   // Label 
    uint32_t    uSDI        :  2;   // Source/Destination ID 
    uint32_t    uData       : 19;   // Data 
    uint32_t    uSSM        :  2;   // Sign/Status Matrix 
    uint32_t    uParity     :  1;   // Parity 
    } 

Reserved for future use.