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Unformatted text preview: (table 6-1). Some of the
actions defined here are used in the definition of other actions. CCSDS 232.1-B-2 Page 6-6 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 NOTE – It should be noted that the COP-1 Frame Sequence Number is an 8-bit field.
Therefore, all arithmetic in the FARM concerning the related fields V(R), N(S)
PW and NW should be performed modulo 256. In particular, this should be
taken into account when reading the event conditions contained in the FARM-1
6.2.2 ‘ACCEPT’ This action involves:
a) placing the FDU contained by the Transfer Frame in a buffer;
b) generating an ‘FDU Arrived Indication’ signal to the Higher Procedures. If a Type-BD
FDU has been placed in a buffer erasing another unread FDU, an optional ‘Aborted
Indication’ may be sent to the Higher Procedures.
6.2.3 ‘DISCARD’ This action involves:
Discarding the received Transfer Frame.
6.2.4 ‘REPORT’ This action involves:
Generating information to be placed in the CLCW based on the current status of
6.2.5 ‘IGNORE’ This action involves no processing by FARM-1.
6.3.1 FARM-1 STATE TABLE
STATE MACHINE FARM-1 is defined as a state machine that is described in a State Table. The basic operation
principle of the state machine is that it remains in a ‘State’ until an ‘Event’ occurs. When an
Event occurs, it is analyzed until it is fully identified and then the Actions specified for the
combination of that Event and that State are executed. Finally, the State variable is updated
with the new State value specified for the combination. The FARM-1 state machine is
described in the FARM-1 State Table in table 6-1.
NOTE – A brief explanation on the format of the State Table is given in annex C. CCSDS 232.1-B-2 Page 6-7 September 2010 RECOMMENDED STANDARD FOR COMMUNICATIONS OPERATION PROCEDURE-1 6.3.2
188.8.131.52 NOTES TO FARM-1 STATE TABLE
Transfer Frame Validation Not included in the FARM-1 State Table are operations concerning the validation of the
Transfer Frame. The event ‘Valid Frame Arrives’ means that the Lower Procedures have
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This document was uploaded on 03/06/2014.
- Spring '14