Document number
205065
Version
Rev. N
Issue date
2019-02-04
Sirius OBC and TCM User Manual
Page
109
of
174
The default configuration of the TC uplink is:
•
Derandomization of telecommands is disabled.
•
Telecommands must include a segment header, see 4.1.3.2.2 in [RD9]
7.2. Block diagram
TCM-S
S
P
A
C
E
W
I
R
E
SpaceWire
Router
03
03
01
01
02
02
UARTs
RS422
/
RS485
RS422
/
RS485
Umbilical
Umbilical
RS422
RS422
LVDS
LVDS
RS422
RS422
C
C
S
D
S
TRX
TRX
Mass memory
NVRAM
Watchdog
W
a
t
c
h
d
o
g
A
D
C
S
C
E
T
TCM core application
Error manager
RAM
System flash
Pulse commands
Pulse commands
RS422
RS422
12
12
Figure 7-1
–
Sirius TCM functionality layout with the external ports depicted
7.3. TCM-S application overview
The TCM-S application is partitioned into several software modules who each handles a
specific functional part. An overview of the software architecture of the TCM-S is presented
in Figure 7.2. A main design driver of the TCM-S software architecture is the ability to pass
along data between the different handlers without copying, since that would quickly
decrease the performance and throughput of the system. To help with the no-copy policy,
each peripheral handling larger amounts of data have DMA functionality, off-loading the
CPU from mere datashuffling tasks while at the same time increasing performance by at
least a magnitude. Data coming in on the SpaceWire interface intended for the mass
memory will thus be stored in RAM only once - in the handoff between the SpaceWire and
mass memory handlers.