"Response to command from spacecraft" (SVC/ITC)

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Focus:	Maintenance / Operation
Structures:	Abstract / Concrete

Context:

Description:

Command confirmation telemetry packet. When executing spacecraft commands, ITC will autogenerate a diagnostic packet, detailing where and when a command is executed as well as the return code for the execution. To identify the command, ITC reflects the command in toto.

Layout:  (hide detail; help)

Response to command from spacecraft (CmdConfirm) Telemetry Packet Format
0x	0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15
000	Version=0			T=0	SH	APID=0x2D0
002	SF		Sequence Count
004	Packet Length=41
006	Timestamp
00E	ITC_NodeID nid								ITC_TaskID tid
010	Time_msui deq_msui
014	Time_lsui deq_lsui
018	Time_msui exe_msui
01C	Time_lsui exe_lsui
020	Status status
024	Drop drp
026	Flags flags
028	CmdHeader cmd_hdr

CmdConfirm (pkt)
|  ITC_NodeID nid (fld)
|  ITC_TaskID tid (fld)
|  Time_msui deq_msui (fld)
|  Time_lsui deq_lsui (fld)
|  Time_msui exe_msui (fld)
|  Time_lsui exe_lsui (fld)
|  Status status (fld)
|  Drop drp (fld)
|  Flags flags (bf)
|  |  pad15 rsv (0-14)
|  |  isTime44 isTime44 (15)
|  CmdHeader cmd_hdr (str)
|  |  Hdr0 hdr0 (bf)
|  |  |  Version ver (0-2)
|  |  |  isCmd isCmd (3)
|  |  |  Sec_hdr sec_hdr (4)
|  |  |  Apid apid (5-15)
|  |  Hdr1 hdr1 (bf)
|  |  |  Seq_flg seq_flg (0-1)
|  |  |  Seq_cnt seq_cnt (2-15)
|  |  Cmd_len cmd_len (fld)
|  |  Hdr3 hdr3 (bf)
|  |  |  Fnc_pad fnc_pad (0)
|  |  |  Fnc_code fnc (1-15)

typedef struct _ITC_CmdConfirm_Tlm {

    /* Telemetry header */
    char                 hdr[14];

    /* ITC node ID */
    char                 nid;

    /* ITC task ID */
    char                 tid;

    /* Time (most significant 32 bits) */
    unsigned int         deq_msui;

    /* Time (least significant 32 bits) */
    unsigned int         deq_lsui;

    /* Time (most significant 32 bits) */
    unsigned int         exe_msui;

    /* Time (least significant 32 bits) */
    unsigned int         exe_lsui;

    /* MSG status code */
    unsigned int         status;

    /* Number of dropped confirmations */
    unsigned short       drp;

    /* Assorted command confirmation flags */
    ITC_Flags            flags;

    /* CCSDS telecommand header */
    ITC_CmdHeader        cmd_hdr;

} ITC_CmdConfirm_Tlm;

Fields:

CmdHeader (index)

Attribute(s):  

Brief:  "CCSDS telecommand header"

Instance(s):  cmd_hdr

CCSDS telecommand header

Drop (index)

Attribute(s):  

Brief:  "Number of dropped confirmations"

Instance(s):  drp

Should memory constraints result in dropped command confirmation packets, the count of dropped packets (on a per task basis) is accumulated and returned in the next successful command confirmation.

Flags (index)

Attribute(s):  

Brief:  "Assorted command confirmation flags"

Instance(s):  flags

Assorted command confirmation flags (only one currently defined: isTime44)

ITC_NodeID (index)

Attribute(s):  LITCNODEID

Brief:  "ITC node ID"

Instance(s):  nid

ITC identifies nodes on the communications network by number. These are the numbers.

ITC_TaskID (index)

Attribute(s):  LITCTASKID

Brief:  "ITC task ID"

Instance(s):  tid

ITC identifies tasks by number. These are the numbers.

Status (index)

Attribute(s):  

Brief:  "MSG status code"

Instance(s):  status

The return code from the routine that executes the command.

Time_lsui (index)

Attribute(s):  

Brief:  "Time (least significant 32 bits)"

Instance(s):  deq_lsui, exe_lsui

Lower half of a WCT_time object (an 8-byte integer measuring nanoseconds since the LAT epoch).

Time_msui (index)

Attribute(s):  

Brief:  "Time (most significant 32 bits)"

Instance(s):  deq_msui, exe_msui

Upper half of a WCT_time object (an 8-byte integer measuring nanoseconds since the LAT epoch).