abaco systems CEI-520 - Ar_Getword; ARINC 429 Receiver Buffer Data Format; ARINC 573;717 Receiver Buffer Data Format; Table 40. ARINC 429 Receive Buffer

Program Interface Library AR_GETWORD
CEI-100/CEI-200/CEI-x20 User’s Manual 99
AR_GETWORD
CEI_INT16 ar_getword (CEI_INT16 board, CEI_INT16 channel,
CEI_INT32 *destination);
This routine gets the next available 32-bit ARINC word from the requested
channel's buffer and puts it in the desired destination. If this routine
successfully returns a word (status is ARS_GOTDATA), there may or may
not be more words in the buffer. This function removes the data from the
buffer and writes it in the specified destination.
Subsequent calls are required to determine if more words are in the buffer.
When it returns ARS_NODATA, the buffer is empty. This is a circular
FIFO buffer that is constantly being maintained by the ARINC interface as
data comes in. The data returned into “*destination” depends on the
channel type as follows:
ARINC 429 Receiver Buffer Data Format
All ARINC 429 receivers return data in the following format:
Table 40. ARINC 429 Receive buffer
31 - 8
7 - 0
Data (MSB-LSB)
Label (MSB-LSB)
Per ARINC convention, the label is transmitted (MSB-first) followed by
the data (LSB-first). The API and the board hardware operate
exclusively on engineering-formatted data.
ARINC 573/717 Receiver Buffer Data Format
Table 41. ARINC 573/717 Receive Buffer
31 – 16
15
14
13 - 12
11 - 0
Time Tag inserted
by firmware
Sync Word
Flag
0 = data
1 = sync
X
Sub Frame
Data (MSB-LSB)
Syntax
Description
Note:
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