1. TRIO-CINEMA FSW- 1 SSL, 8/10/2010 Flight Software Seyoung Yoon and Sameet Ramakrishnan Space Sciences Laboratory Kyung Hee University University of California, Berkeley

2. TRIO-CINEMA FSW- 2 SSL, 8/10/2010 Overview Helium Cmds Analogs I II IVIII Simulink PWR.A ACS.A Sun Sensors Sun Sensors Torque Coils Torque Coils STEIN Atten STEIN Atten MAG Elect MAG Elect STEIN Elect STEIN Elect MAG.A STEIN.A SPI S-Band Tx S-Band Tx TM.A SDCARD STEIN FPGA POWER Switches Timers MAG FPGA BKG.A EXEC.A SSR.A LD.A CMD.A SRAM & EEPROM SRAM & EEPROM HSK.A COMM FPGA FSW MAJOR MODULES SPI

3. TRIO-CINEMA FSW- 3 SSL, 8/10/2010 Tasks Two kinds of tasks – Foreground tasks (called by EXEC module) Run asynchronously in available time No hard limit on execution time Configurable by ground commands Will be frequently interrupted by Background commands, so should not rely on IO peripheral state Attitude Control System (ACS), SRAM scan, memory peek/poke… – Background tasks (called by BKG module) Interrupts fired at 1024 Hz Run at specific times Must complete before next interrupt (~9700 instructions) Performs tasks that must occur on time Data flow management, MAG sampling, housekeeping (analog) ADC sampling…

4. TRIO-CINEMA FSW- 4 SSL, 8/10/2010 Background Task Table HSKSTETXSTEMAGSTETXSTE HSKSTETXSTE TXSTE TXSTEMAGSTETXSTE CMDSTETXSTE TXSTE HSKSTETXSTEMAGSTETXSTE TXSTE TXSTE TXSTEMAGSTETXSTE TXSTE TXSTE

5. TRIO-CINEMA FSW- 5 SSL, 8/10/2010 Overview Background module completed and tested EPS module completed and tested SD card drivers in progress –Drivers have since been completed, and circular buffers on SD card have been built Transmission module mostly completed –“Overflow” packet handling not complete –Support for Memory Dump Packets needed –Error handling –Testing

6. TRIO-CINEMA FSW- 6 SSL, 8/10/2010 Overview

7. TRIO-CINEMA FSW- 7 SSL, 8/10/2010 Real Time Clock (RTC) Description: –Time-stamping science data –Scheduling Commanded events –Referencing ACS “ephemeris” –Set via ground command –Offset maintained for drift Progress : –Built interface library (over I2C) –Initialize, read, start/stop, halt/unhalt Future : –Finalize details of maintaining offset. –Potential addition of a background task to automatically correct drift?

8. TRIO-CINEMA FSW- 8 SSL, 8/10/2010 Data Handling HSK Module Transmission Module Transmission Module Fast Digital HSK Fast Digital HSK ACSACS ACSACS EPSEPS EPSEPS SD Card SD Card Slow Digital HSK Slow Digital HSK Analog HSK Analog HSK STEIN Module STEIN Module MAG Module MAG Module SteinDataBuff[ ] MagDataBuff[ ] HskDataBuff[ ]

9. TRIO-CINEMA FSW- 9 SSL, 8/10/2010 Housekeeping Overview Schedules sampling of analog inputs, EPS values, state of software and peripherals –Sample rate 16Hz –Packet refresh rate 10 seconds Timestamps and packetizes information for downlink –During orbit, the blocks are stored onto the SD card –During downlink period, the blocks are directly down-linked at next available opportunity New “recent” block sent approximately every 10 seconds Maintains updated record of EPS solar currents for ACS –Sample rate 32 Hz, 6 values so.1875 second refresh rate

10. TRIO-CINEMA FSW- 10 SSL, 8/10/2010 Housekeeping Packet Format First 80 bytes “slow digital housekeeping” –Timestamp + General program state –Actuators Status –Power Status –ACS/Sun Sensor? –MAG Housekeeping, STEIN housekeeping 7 repeated blocks of 60 bytes each –Updated ~2 second rate limited by sampling all EPS values) –Analog Housekeeping from EPS –Analog inputs into microcontroller –Fast Digital Housekeeping Torque coils status, Spin Rate, Elevation from ACS SSR state

11. TRIO-CINEMA FSW- 11 SSL, 8/10/2010 Housekeeping Status Progress: –Sampling analog inputs, retrieving EPS, framework for retrieving digital value completed –ACS solar current refreshing completed –Packetization completed (for now…) Future: –CTM finalization*! –Digital values filled into framework as they become available –Action/Error log (maybe not here) Overflow packets? –I2C error handling, testing

12. TRIO-CINEMA FSW- 12 SSL, 8/10/2010 Housekeeping Verification Demonstration later in the week?

13. TRIO-CINEMA FSW- 13 SSL, 8/10/2010 Command Module Description DMAs uplinked commands from radio into PIC’s DMA RAM –Serial UART2 -> DMA RAM –By comparing uplink rate against CMD module interrupt rate, we can calculate necessary DMA buffer size (~75 bytes) Sorts commands from DMA RAM into 1 of 2 lists in non DMA RAM: immediate command list or delayed command table –Delayed Commands buffered for the duration of the orbit –Immediate Commands received and handled “immediately” Initiate downlink, request packet, mode switches, etc. Provides functions for EXEC to access these lists

14. TRIO-CINEMA FSW- 14 SSL, 8/10/2010 Command Progress Immediate Command handling completed –Implemented as a circular buffer data structure Delayed Commands currently handled as “table” Delayed Packet with entries of 6 bytes Maintains a 4 byte “time field” and a 2 byte “command field” Table “halted”, reloaded, restarted Originally linked list Lots of space overhead for the flexibility of inserting commands in correct temporal location Does not seem necessary/consistent with table structure/large one shot packet uploads Limits number of commands total that can be stored, adds software execution time overhead –Sorting more of a ground task anyways? These decisions must still be made

15. TRIO-CINEMA FSW- 15 SSL, 8/10/2010 Command Module Verification

16. TRIO-CINEMA FSW- 16 SSL, 8/10/2010 Command Future/Problems Command uplink format finalization –How many commands? Space on dsPIC? Sorted? –Delayed Command Table manipulation post uplink Deletion Insertion? Modification? Verification/error checking of uplinked commands –CRC verification scheme needed? –Redundancy? General error handling needed Needs testing under larger data rates

17. TRIO-CINEMA FSW- 17 SSL, 8/10/2010 STEIN Module Description Single point of entry for SSR writes –Scheduled frequently enough that this makes sense –May “absorb” other modules with busy times HSK, MAG blocks –Error handling from a single place Retrieve, timestamp, packetize STEIN data from FPGA –Force packet writes at minimum every 1 second Hardware timestamp rollover

18. TRIO-CINEMA FSW- 18 SSL, 8/10/2010 STEIN progress Able to write blocks (STEIN, MAG, HSK) to SD card –Primitive scheduling system Error handling/reset sequence completed –Hard/Soft Reset Retrieval and Packetization of Stein data completed –Refer to CTM for Stein packet format –One second force needs “hardware support”

19. TRIO-CINEMA FSW- 19 SSL, 8/10/2010 STEIN Module Future Handle potential changes in software requirements from instrument side –Currently just assumes arbitrary 32 bit values, doesn’t parse data at all –Change in STEIN packet format, some status bytes/meta data needed? Needs testing with FPGA, STEIN hardware Ensure Stein packet format is acceptable

20. TRIO-CINEMA FSW- 20 SSL, 8/10/2010 Magnetometer Description Description –Interacts with MAG through I2C interface to FPGA –Initializes hardware –Schedules and commands sampling (based on mode) Baseline of 64Hz, divided down for slower sampling –Controls mode switching/power settings Via ground command –Packetizes data Repeat of status byte, 4 24 bit vectors (1 for each axis and OB temperature) Inboard temperature replacement –Maintains shared values for ACS –CPD for full details on all the nuances Progress –Done “in theory”, but needs testing with real hardware

21. TRIO-CINEMA FSW- 21 SSL, 8/10/2010 Conclusion and Future Tasks Review and finalization of the CTM –Will allow finalization of the Housekeeping, Command, Transmission modules Tying modules together –Implementation of the EXEC module/command parsing –Testing modules together, and with GSEOS Verification of software with hardware –IIB, MAG and eventually STEIN Integration of ACS code with FSW Load Module