Reference Manual AFDX / ARINC 664 Application Interface Library
165
Section 4 – Function Reference: Receiver Functions
One Entry specifies one Message, which means one complete SAP port message. For special
system information and administration a Fix sized Header is preceded.
The following picture shows the schematic of such an entry.
SAP Message Buffer Layout
31
24
23
16
15
8
7
0
Time Tag High
Time Tag Low
Message Size
IP Source Address
UDP Source Port
SAP Header Reserved
SAP Frame
Received SAP- FRAME
(sampling message: up to SAP payload (1 – 1471 bytes
queuing message: up to 8Kbytes)
Figure 4.4.2.3-1: RX SAP Message Buffer Layout
T
T
Y
Y
_
_
S
S
A
A
P
P
_
_
B
B
U
U
F
F
F
F
E
E
R
R
_
_
H
H
E
E
A
A
D
D
E
E
R
R
This is a structural description of the SAP header
typedef struct sap_buffer_Header {
TY_FDX_FW_IRIG_TIME
x_FwTimeTag;
AiUInt32
ul_BufferSize;
AiUInt32
ul_IPSrc;
AiUInt32
ul_UDPSrcPort;
AiUInt32
ul_Reserved;
} TY_SAP_BUFFER_HEADER;
T
T
Y
Y
_
_
F
F
D
D
X
X
_
_
F
F
W
W
_
_
I
I
R
R
I
I
G
G
_
_
T
T
I
I
M
M
E
E
x
x
_
_
F
F
w
w
I
I
r
r
i
i
g
g
T
T
i
i
m
m
e
e
The Firmware IRIG Time Tag information is from last received message. In case of a queuing
port where the messages can be fragmented it is the Time Tag of the last received fragment.
typedef struct {
AiUInt32
ul_TtHigh;
AiUInt32
ul_TtLow;
} TY_FDX_FW_IRIG_TIME;
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
T
T
t
t
H
H
i
i
g
g
h
h
;
;
Timetag word in firmware format. The higher part of the time tag, containing the minutes
of hour, hours of day and day of year.
For further description see Firmware specification.
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
T
T
t
t
L
L
o
o
w
w
;
;
Timetag word in firmware format. The lower part of the time tag, containing the
Microseconds of second, seconds of minutes and minutes of hour.
To get a ‘C’ structured information of the Time Tag you can use the functions
FdxFwIrig2StructIrig ().
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
M
M
s
s
g
g
S
S
i
i
z
z
e
e
;
;
SAP payload size in bytes of received Frame.
