Aim MIL-STD-1553 - Page 173

MIL-STD-1553 Reference Manual
159
Chapter 5 – Buffer Functions
For Transmit Operation the following options are valid:
Value
Constant
Description
0
API_BSM_TX_KEEP_SAME
Keep the same Data Buffer at transfer
error
1
API_BSM_TX_GO_ON_NEXT
Go on with the next Data Buffer in the
Buffer Queue
0xFFFFFFFF
-
Do not modify this parameter
Note: The data buffer store mode is always evaluated at the
‘Transfer-End’:
‘bsm’ = 0: If a transfer error is detected at the ‘Transfer-
End’, the Buffer is not valid!
‘bsm’ = 1: At ‘Transfer-End’ the Buffer is always valid
and it does not matter, if a transfer error is detected or not. If
an error occurred during a RT-BC or RT-RT transfer, the BC
terminates the transfer with the error detection. Thus, the
possible remainder of the transfer after the error will not be
stored in the buffer.
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
B
B
u
u
f
f
f
f
e
e
r
r
S
S
i
i
z
z
e
e
M
M
o
o
d
d
e
e
0xFFFFFFFF (reserved)
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
B
B
u
u
f
f
f
f
e
e
r
r
S
S
i
i
z
z
e
e
Buffer size definition
A full-size MILBus transfer needs 16 longwords. A maximum buffer size of 31 longwords allows
the application software to store application dependant data up to 15 longwords (60 bytes) in
the buffer area.
Value
Description
0
Reserved
1..31
Buffer size in longwords
0xFFFFFFFF
Do not modify this parameter
A
A
i
i
U
U
I
I
n
n
t
t
3
3
2
2
u
u
l
l
_
_
B
B
u
u
f
f
f
f
e
e
r
r
Q
Q
u
u
e
e
u
u
e
e
M
M
o
o
d
d
e
e
Buffer Queue Mode
Value
Constant
Description
0
API_BQM_CYCLIC
Cyclic data storage
1
API_BQM_STAY_LAST
Store once and stop at end of queue
(last index) and reuse last buffer
2
API_BQM_HOST_CONTROLLED
Do not advance automatically to next
buffer (host controlled)
3
Reserved until status queue is
supported
0xFFFFFFFF
-
Do not modify this parameter
Note: The Buffer Queue Mode is only processed, if the “Buffer is
valid”. The Buffer Queue Modes affect the Current Buffer
Index and thus (in the future) the Status- and Event Queue
Operation of the BC!