Aim MIL-STD-1553 - Apicmdbcini

MIL-STD-1553 Reference Manual
225
Chapter 7 – Bus Controller Functions
7.1.13 ApiCmdBCIni
Prototype:
AiInt16 ApiCmdBCIni ( AiUInt32 ul_ModuleHandle, AiUInt8 biu, AiUInt8 retr, AiUInt8 svrq,
AiUInt8 tbm, AiUInt8 gsb );
Driver Command:
API_BC_INI (0x70)
Purpose:
This function is used to initialize the Bus Controller mode of the AIM board. This must
be the first BC function called.
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Defines the number of retries which shall be performed by the BC, if a transfer is
erroneous. The retry mechanism and bus switching method works as follows:
Retry on the same bus until the retry count (internally used value) is decremented to
zero, then switch the bus and try once more again on this bus.
Value
Constant
Description
0
API_DIS
Retry disabled
1
API_RETRY_1ALT
One retry on the alternate bus
2
API_RETRY_1SAME_1ALT
One retry on the same bus, one retry
on the alternate bus
3
API_RETRY_2SAME_1ALT
Two retries on the same bus, one retry
on the alternate bus
The switching remains permanent for all transfers in “Global Transfer Bus Mode”
(see parameter ‘tbm’), or for the single transfer in “Transfer Specific Bus Mode”,
respectively. Afterwards, the bus remains in this state until it is switched again by
the application software or as a result of another retry sequence. The different bus
modes can be defined with the parameter ‘tbm’ of this function.
Note: When set to retry disabled, the retry of individual BC transfers cannot
be enabled using ApiCmdBCXferDef.
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Service Request / Vector Word Mode Control
Value
Constant
Description
0
API_DIS
Disable
1
API_ENA
Enable
Note: If RT capability of the AIM board is used for simulatiuon of Mode code
16, the function ApiCmdRTSACon shall set ‘smod’=3 and
‘swm’=0xFEFF in order to reset the Service Request Bit of the Status
Word response automatically!
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