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ISUAL Instrument Software. S. Geller. Processors Used Startup Status Telemetry Command Processing Command Echo Science Startup Mass Memory Initialization Data Compression Module Initialization Setting High Voltages Filter Wheel and Heater control. Aurora Mode Aurora Science Products
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ISUAL Instrument Software S. Geller
Processors Used Startup Status Telemetry Command Processing Command Echo Science Startup Mass Memory Initialization Data Compression Module Initialization Setting High Voltages Filter Wheel and Heater control Aurora Mode Aurora Science Products Photometer Sampling Rates Camera Readouts Aurora Mode Parameters Sprite Mode Sprite Science Products Photometer Sampling Rates Camera Readouts Sprite Mode Parameters Dayside Processing Development Tools Compilers, Simulators, Version Control Instrument Software Overview NCKU UCB Tohoku Instrument Software S. Geller
Processors Used • DPU • 8085 processor • Assembly Language, heritage from IMAGE/FUV • Primary purpose: Overall control and sequencing • DSP • Fast Signal Processor • Software developed by NCKU • Primary purpose: Data Compression NCKU UCB Tohoku Instrument Software S. Geller
ISUAL Modes • Standby • Aurora/Airglow Observing • Sprite Observing • Dayside Data Readout NCKU UCB Tohoku Instrument Software S. Geller
Startup - Power On Status • All power services off • HV values set to zero • Heaters off • Mass Memory off • DCM off • No automatic turn-on of anything. NCKU UCB Tohoku Instrument Software S. Geller
Power-On Telemetry • Status telemetry (SOH) generated • Command echoes • No Science TLM • Command processing is active • Command echoes are generated in status telemetry NCKU UCB Tohoku Instrument Software S. Geller
Changes from Power-On Status • Any changes will be the result of receiving a ground command. • Time-tagged commands are stored in ordinary RAM, which means they are lost when power goes off. NCKU UCB Tohoku Instrument Software S. Geller
Status Telemetry • Uses Transmit side of OBMU channel • Information sent asynchronously • SOH data is sent every 30 seconds (may be commanded to go faster). • SOH data is sent in all ISUAL modes • The spacecraft stores the SOH data between ground contacts. NCKU UCB Tohoku Instrument Software S. Geller
SOH Packet • Sent as CCSDS packet • Includes Time of SOH, Mode • Voltages, Currents, Temperatures • Last Command • Number of commands executed • Fault Flags NCKU UCB Tohoku Instrument Software S. Geller
Command Echo Packet • Sent on status channel whenever a command is received by ISUAL • Encapsulated in a CCSDS packet • Multiple echoes possible in one packet NCKU UCB Tohoku Instrument Software S. Geller
Command Input • Commands are generated either by spacecraft or from Ground Station • Commands from Ground are generated using STOL • Command input uses receiver side of OBMU channel. • Commands are strings of bytes, received one byte per interrupt; DPU puts the bytes on a queue. • The command interpreter reads the queue, verifies checksums and sets up the commands for execution. NCKU UCB Tohoku Instrument Software S. Geller
Command Types • TPA command is generated by the spacecraft; ApID=700 hex • All other commands come from the ground; ApID=701 hex (up to 70F are assigned to ISUAL). • Command opcode is first byte of data. NCKU UCB Tohoku Instrument Software S. Geller
Time-Tag • Commands with no secondary header are executed immediately. • Time-tagged commands have a secondary header, which gives the UT when the command is to be executed by ISUAL. NCKU UCB Tohoku Instrument Software S. Geller
Setting ISUAL Time • ISUAL can run without a time-set. Clock starts running from year 0, day 0, hms=0:0:0, but an SOH status byte says that time has not yet been set. • ISUAL receives time in a Time-Position-Attitude (TPA) command. The time is effective as of the next 1-second PPS tick. • A PPS tick generates an interrupt NCKU UCB Tohoku Instrument Software S. Geller
Command Echo Data • opcode of echoed command • sequence number of echoed command • Exec code: • 0=executed • 1=queued (was time-tagged) • time when executed/queued • result code • (OK, or errors like invalid opcode) NCKU UCB Tohoku Instrument Software S. Geller
Command Echo Packet • Number of Echoes in this packet • Up to 32 Echoes NCKU UCB Tohoku Instrument Software S. Geller
NCKU UCB Tohoku Instrument Software S. Geller
NCKU UCB Tohoku Instrument Software S. Geller
Science Startup • Must be done when in Standby mode, before taking data • Not required if changing among Aurora, Sprite or Dayside modes. • Invoked by I_SCIENCE command NCKU UCB Tohoku Instrument Software S. Geller
I_SCIENCE Command • Initialize Mass Memory • Initialize DCM • Set mode: • Aurora • Sprite - Burst • Sprite - Continuous • Initialize and start TM generation NCKU UCB Tohoku Instrument Software S. Geller
Mass Memory Initialization • Turn on Mass Memory power • Memory test; update bad-memory map. • Allocate Mass Memory Control Blocks • for DCM,Camera, Spectrophotometer and Array photometer • Allocate TM area • for building packets, PVCFs and 64 Megabit “files”. NCKU UCB Tohoku Instrument Software S. Geller
Data Compression Module (DCM) Initialization • Turn on DCM • DCM shows “busy” until it completes its internal checks • Copy DSP program from EEPROM to MM • Set up initial “do nothing” MMCB • Issue CDI commands • tell DCM where in MM it can get its initial MMCB and DSP program NCKU UCB Tohoku Instrument Software S. Geller
Setting High Voltages • Levels are set by loading registers • HV levels not active until a particular HV power service is turned on • Commands to set HV registers must be preceded by “May-I” command, with 4 code bytes. NCKU UCB Tohoku Instrument Software S. Geller
Camera HV Settings • Camera - MCP • Day • Night (Aurora) • Night (Sprites) • Camera - Phosphor • Day • Night (Aurora) • Night (Sprites) NCKU UCB Tohoku Instrument Software S. Geller
Spectrophotometer HV Settings • 6 HV power supplies • Day • Night (Aurora) • Night (Sprites) • total of 6 x 3 = 18 settings NCKU UCB Tohoku Instrument Software S. Geller
Array Photometer HV Settings • 2 HV power supplies • Day value • Night value • total of 2 x 2 = 4 settings • Commanded by DPU via CDI NCKU UCB Tohoku Instrument Software S. Geller
Heater Control • “Open Loop” • Table is loaded for each heater, giving: • number of seconds on • number of seconds off • Each heater can be commanded to: • Active (cycling) • Off (always off) NCKU UCB Tohoku Instrument Software S. Geller
Filter Wheel operation • Command: I_FILTER_SET index=n • rotate filter wheel to position n • DPU ensures that camera exposures have been paused before moving the filter wheel. • DPU selects position index, then gives a “start” • status bit signals that filter has stopped • error conditions? NCKU UCB Tohoku Instrument Software S. Geller
Aurora Mode NCKU UCB Tohoku Instrument Software S. Geller
Aurora Mode Setup • HV values set in registers • Heaters cycling • Initial Filter set • Do Science Setup • I_SCIENCE command, select Aurora mode NCKU UCB Tohoku Instrument Software S. Geller
Aurora Science Products • Aurora Picture: • Taken at regular intervals • Fixed exposure length, filter • Spectrophotometers: • M Averages of the 6 Spectrophotometer detectors • Array Photometers: • TBD • Pair of TPA to determine pointing NCKU UCB Tohoku Instrument Software S. Geller
Spectrophotometer • Fixed rate: 1000 samples/sec • 6 Sensors, with separate HV settings NCKU UCB Tohoku Instrument Software S. Geller
Spectrophotometer Sampling • Continuous sampling while in Aurora mode • Not synchronized to Camera exposures • NS samples will be taken and stored into an MM area. • The NS samples are averaged (by the DCM) • Result is MS groups of 6 integer values. • NS=1000 MS=5 NCKU UCB Tohoku Instrument Software S. Geller
Spectrophotometer Averaging • Spectrophotometer fills memory with NS samples, then switches to a different readout area. • DPU gets an interrupt on the switch, and stores the time of the first sample of the new group. • Old sample group goes to the DCM for averaging. NCKU UCB Tohoku Instrument Software S. Geller
Array Photometer • 16 channels with one filter, HV • 16 channels with another filter, HV • sampling rate is fixed NCKU UCB Tohoku Instrument Software S. Geller
Array Photometersampling • Continuous sampling while in Aurora mode • Not synchronized to Camera exposures • NA samples will be taken and stored into an MM area. • The NA samples are averaged (by the DCM) • Result is MA groups of 32 integer values. • NA=1000 MA=5 NCKU UCB Tohoku Instrument Software S. Geller
Array Photometeraveraging • Array photometer fills memory with NA samples, then switches to a different readout area. • DPU gets an interrupt on the switch, and stores the time of the first sample of the new readout. • Old sample readout goes to the DCM for averaging. NCKU UCB Tohoku Instrument Software S. Geller
Camera Readouts • MM-Camera interface has registers for two readout areas. • After a readout is complete, camera automatically switches to the other area for the next readout. • DPU gets an interrupt when the switch occurs. NCKU UCB Tohoku Instrument Software S. Geller
Aurora Modeparameters • Camera • Filter • exposure length (100 ms?) • Interval between exposures (1 minute?) • Spectrophotometer NS, MS • Array Photometer NA,MA NCKU UCB Tohoku Instrument Software S. Geller
Aurora Mode Data Cycle • DPU starts Camera exposure at regular intervals • notes start time • waits for camera to readout exposure. • While this is going on, DPU captures samples from both Photometer units. • Data is sent to DCM • Compressed data is sent as TLM packets NCKU UCB Tohoku Instrument Software S. Geller
NCKU UCB Tohoku Instrument Software S. Geller
Sprite Mode NCKU UCB Tohoku Instrument Software S. Geller
Sprite Mode Setup • HV values set in registers • Heaters cycling • Initial Filter set • Do Science Setup: I_SCIENCE mode= • Sprite-Burst • Sprite-Continuous NCKU UCB Tohoku Instrument Software S. Geller
Sprite Mode Setup (cont.) • Select Trigger Photometer • Set trigger level NCKU UCB Tohoku Instrument Software S. Geller
Camera Readouts • Camera interface has registers for two readout areas. After all the images from an event are stored in MM, the camera automatically switches to the other area to readout the next event. • DPU gets an interrupt for each Sprite Event • DPU gets a (different) interrupt for each readout switch. NCKU UCB Tohoku Instrument Software S. Geller
Sprite Science Productsin burst mode • Up to 8 Sprite Images • pre-trigger (1) • event (1) • post-trigger (up to 6 more) • Spectrophotometer and Array Photometer samples covering duration of Sprite event • Pair of TPA to determine pointing NCKU UCB Tohoku Instrument Software S. Geller
Science Products incontinuous mode • Up to NC Sprite Images • pre-trigger (5) • event (1) • post-trigger (NC-1-5) • Spectrophotometer and Array Photometer samples covering duration of Sprite event • Pair of TPA to determine pointing NCKU UCB Tohoku Instrument Software S. Geller
Photometer Sampling • Prior to Sprite Event, samples are taken continuously. • Each sample is read out into a circular buffer of NPS (NPA) samples; the oldest samples are over-written. NCKU UCB Tohoku Instrument Software S. Geller
Photometer Sampling (cont.) • The idea is for the photometer samples to cover the time period of the Event, pre and post trigger. NPS and NPA should be set to enough samples to cover a Sprite interval. • On the Sprite Event interrupt, the DPU reads a register to identify the Event sample (memory address). NCKU UCB Tohoku Instrument Software S. Geller
Photometer Sampling (cont.) • DPU waits until a camera readout is complete, then commands the photometers to switch to their alternate circular buffers. • DPU captures sample group, and the index of the Event sample, sends it to DCM • DPU sets new alternate circular buffer addresses, ready for next Sprite Event. NCKU UCB Tohoku Instrument Software S. Geller