OBC Subsystem

Serial Interface

Baud: 115200

Line ending: CRLF

Recommended serial terminal: miniterm.py

The OBC does not echo back characters as you type, but it will send back the full command it received once you hit enter (i.e., when the OBC encounters a CRLF EOL sequence).

Current command format follows the structure of:

<command> <subcommand> [<args>...]

Overview

Here are the useful commands that are currently implemented:

get tasks
get runtime
get heap
get minheap
task suspend <id>
task resume <id>

get

Get various metrics from the OBC.

tasks

Show state, priority, and free stack of running tasks. Note that the Num column is not the task id used for other commands. See the TASK_IDS enum in sfu_cmds.h_ for task ids.

Task            State   Prio    Stack   Num
serial          R       3       38      7
IDLE            R       0       103     5
state           B       3       260     10
tickle          B       4       95      9k
main            B       2       52      1
FreqPST         B       1       54      2
radio           B       5       77      8
InfreqPST       B       1       45      3
Receiver        B       2       49      4
blinky          S       1       99      6

runtime

Show task CPU utilization statistics.

Task            Abs             Perc
serial          13409184                1%
IDLE            954919186               95%
tickle          57110           <1%
main            3053180         <1%
FreqPST         51296           <1%
state           14571           <1%
InfreqPST       12141           <1%
Receiver        510286          <1%
radio           30604595                3%
blinky          54453           <1%

heap

Show amount of heap currently available.

4440 bytes

minheap

Show lowest amount of heap ever reached.

3352 bytes

task

Run various task-related commands.

suspend <id>

Suspend the task with id <id>

For example, from TASK_IDS, we see that TASK_RADIO has an ID of 1. Thus, the following command will suspend the radio task.

task suspend 1

resume <id>

Resume the task with id <id>

The following command will resume the radio task, TASK_RADIO.

task resume 1

Check the CMD_TABLE macro in sfucmds.h for the list of registered commands. Commands are implemented in sfucmds.c.

Command sched is implemented but not tested, reason being the current parsing for this command expects to recieve the raw byte representation of the command to schedule. This is assisted by parsing the argument as hexadecimal characters, but of course is still not feasible to input manually. Won’t matter too much since there are easier ways to test the scheduling system, such as:

• Hardcode a variety of sched struct and populate it with simple fields retrieved from serial commands, then fire these off into the scheduling system.
• Test scheduling system using the radio.

Radio SPI Interface

TODO