MA28140 Datasheet, PDF (30/72 Pages) Dynex Semiconductor – Packet Telecommand Decoder

MA28140
5.3 TELEMETRY INTERFACE
The Telemetry interface allows four different reporting
words to be retrieved.
• the Command Link Control Word (CLCW),
• the Command Pulse Distribution Unit Status (CPDUS),
• the Frame Analysis Report (FAR),
• the Authentication Unit Status (AUS).
• TMMOD = 1; the status (CPDUS, FAR, AUS) reports
are fetched with 2 sample signals.
Both interfaces use the same TMC and TMD signals.
When the parallel interface is selected it is not possible to use
the TM (and MAP) serial interface, except for the CLCWB
interface which can be used in a serial mode even if the PAR
signal is set to 1. The protocol for the serial interface is fully
compliant with section 4.3 of TTC-B-01 (serial 16 bit digital
channel).
It is possible for an application to use either a serial or
parallel interface to read these reports. The selection between
serial or parallel interface is made with the configuration input
pin PAR as follows:
• PAR = 1; the parallel TM interface is used
• PAR = 0; the serial TM interface is used
The parallel interface is described in section 5.4. The
parallel interface is useful for integrating subsystems
comprising both the TC decoder and a processor, without
cross-coupling after the TC decoders. The CLCW has its own
serial telemetry interface which is redundant in serial mode.
The other three reports (CPDUS, FAR, AUS) can be
fetched through a common serial interface (clock and data
lines) using two or five different sample signals. The selection
between using two or five sample signals is made with the
configuration input pin TMMOD as follows:
• TMMOD = 0; the status (CPDUS, FAR, AUS) reports
are fetched with 5 sample signals.
Serial CLCW Interface
The 16 bit Command Link Control Word (CLCW) can be
retrieved through this interface. The serial CLCW interface is
redundant in order to allow two separate redundant TM
encoders to be connected to each TC decoder. Figure 12
shows the serial CLCW telemetry interface. The serial
interface is implemented with 3 signal lines:
• CLCWSA: status sample input,
• CLCWCA: status clock input,
• CLCWDA: status data output.
The redundant serial CLCW interface is identical with the
nominal serial CLCW interface using the 3 signals:
• CLCWSB: status sample input,
• CLCWCB: status clock input,
• CLCWDB: status data output.
CLCW Serial Interface
PTD
CLCWSA
CLCWCA
CLCWDA
APPLICATION
Telemetry
Systems
PAR = 0
Note: The 0 bit is the MSB and is transmitted first.
Figure 12: Serial CLCW Telemetry Interface
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