CSP Interfaces

The Polaris receiver is operated remotely via CubeSat Space Protocol (CSP) messages. The Polaris Client Library, Property Client Library, and BTP Client Library all contain wrapper function around CSP protocols. In addition, Polaris also implements the standard CSP service ports such as CSP_PING and CSP_REBOOT.

Configuration CSP parameters

By default, the receiver uses address 20 but this can be changed by adjusting the address property sys.csp.address and saving the sys group. The system must be rebooted for the address change to take effect.

The receiver supports CSP via CAN-bus (CAN interface) and RS-422 (KISS interface) in the P1 connector. Both interfaces are always enabled for incoming messages, but the default routing table sends egress messages on the CAN interface for all traffic except loopback.

The current routing table can be listed using the csp route show command in the debug shell:

[polaris] csp route show
20/5 LOOP
0/0 CAN

The results are listed using CIDR notation. CSP addresses are 5 bits long so, 20/5 is an exact match to address 20, i.e. the loopback address. 0/0 marks the default route. To adjust CSP routing, the sys.csp.routes property should be used. As an example, to send all traffic via the RS-422/KISS interface set the property to 0/0 KISS and save the sys group. It is not necessary to add an explicit route for the loopback interface.

The CSP connection can be tested using the csp ping debug shell command. This can be combined with the watch command to e.g. ping a system 10 times and report the number of successful replies. This example pings address 1 with 100 byte frames:

[polaris] watch -c10 -s csp ping -s100 1
Running command 'csp ping -s100 1' every 1000 ms
Reply in 4 ms
Reply in 4 ms
Reply in 4 ms
Reply in 4 ms
Reply in 5 ms
Reply in 5 ms
Reply in 4 ms
Reply in 4 ms
Reply in 4 ms
Reply in 6 ms
10 executions, 10 success 0 failures