Aim MIL-STD-1553 - Page 131

MIL-STD-1553 Reference Manual
117
Chapter 3 – System Functions
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‘fct’
Value
Value
1..4
0..n
Upper Limit of the System Dynamic Data Word
5
0..n
Amount of contiguous Dataset Buffers
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1..32
Amount of contiguous words from specified Dataset Buffer ID
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0
Reserved
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0..31
Checksum End Word Position
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‘fct’
Value
Constant
Value
1..4
0..n
Stepsize used to increment or decrement
the System Dynamic Data Word
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0
1
API_SYSTAG_STEP_CYCLIC
API_SYSTAG_STEP_KEEP_LAST
Cyclic operation
Keep last Buffer of Dataset
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1
API_SYSTAG_STEP_CYCLIC
API_SYSTAG_STEP_KEEP_LAST
Cyclic operation
Keep last Word of States
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API_SYSTAG_STEP_1S_COMP
API_SYSTAG_STEP_2S_COMP
1's Complement
2's Complement
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API_SYSTAG_STEP_CHECKSUM_PLUS
Checksum is calculated by adding all data
word values from word position ‘min’ to
‘max’
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API_SYSTAG_STEP_CHECKSUM_XOR
Checksum is calculated by xoring all data
word values from word position ‘min’ to
‘max’
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API_SYSTAG_STEP_CHECKSUM_1760
1760 Checksum is calculated from all data
words preceding the specified Checksum
word position ‘wpos’ (‘min’ & ‘max’ are n/a)
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‘tag_fct’
Value
Value
1..4, 6, 7, 8
0..31
Word Position of the System Dynamic Data Word in the Transmit Buffer
5
0
Reserved
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'fct'
Bit 15
Bit 14
Bit 13
Bit 12
Bit 11
Bit 10
Bit 9
Bit 8
1..4, 6
BIT_POS
5, 7, 8
0 (Reserved)
'fct'
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
1..4, 6
BIT_NB
5, 7, 8
0 (Reserved)
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Value
Value
0..15
Position of LSB in System Dynamic Data Word
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Value
Value
1..16
Amount of bits in System Dynamic Data Word
0
Identical to 'BIT_NB' = 16
Output
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Return Value
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All API functions return API_OK if no error occurred. If the return value is not equal
to API_OK the function ApiGetErrorDescription can be used to obtain an error
description.