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Command and Data Handling

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8 channel 10 bit ADC. Open source WinAVR C compiler. Burr-Brown (TI) ADS7828 ADC ... MAX1472 CW Transmitter. AD8354 RF Gain Block. Block Diagram. Solar Cells ... – PowerPoint PPT presentation

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Title: Command and Data Handling


1
Command and Data Handling
  • Gather, process, format, and store science and
    housekeeping data
  • Validate and execute commands
  • Provide some level of autonomy
  • Control all functions of the satellite

2
Hardware
  • Low power
  • Low Voltage ( less than 3.7V )
  • Small footprint
  • Inexpensive
  • Legacy

3
(No Transcript)
4
ATmega2561L ATmega1281L
  • Atmel AVR 8-bit
  • Large 128/256kB program memory
  • Two Wire, SPI, USART
  • 2.7V, 15mW
  • 8 channel 10 bit ADC
  • Open source WinAVR C compiler

5
Burr-Brown (TI) ADS7828 ADC
  • I2C, 12 bit, 8 channel multiplexer
  • 0.75 mW power dissipation

6
Other hardware
  • N-channel enhancement Power MOSFETs
  • 32 Mbit external flash memory, SPI
  • Real Time clock with battery backup and alarm,
    I2C
  • Microcontroller supervisor, under voltage
    protection, WDT, master reset, I2C
  • Current sensing amplifiers

7
CDH Hardware Summary
8
Hardware Progress
  • All components selected
  • Complete subsystem schematic
  • Begun PCB layout
  • must complete for testing and programming

9
Software
  • Procedural, Interrupt driven design
  • All code written in C
  • Four modes of operation
  • Normal
  • Idle
  • Safe
  • Transmit

10
(No Transcript)
11
Programming Status
  • Have compilers, development platforms,
    testing equipment
  • Well defined
  • Programmed USART, internal ADC, general I/O

12
BEACON
Continuous Wave Transmitter/Receiver System
  • Will always broadcast identifying signal
  • Ground will track AS-I by this signal and then
    engage main COMM
  • Will broadcast predetermined error message in
    case of main COMM failure
  • Transmit power estimated to be .5W 1W in the 70
    cm range

13
Beacon Schematic
14
K-ID Chip
15
MAX1472 CW Transmitter
16
AD8354 RF Gain Block
17
Block Diagram
04-25-2007
17
AubieSat-I Design Review, Spring 2007
18
Energy Storage
  • Two Lithium-Ion batteries will be used to store
    energy.
  • Each battery is rated for 1.7Ah, which is roughly
    18,115 Joules, under specific conditions.
  • The open circuit voltage on the batteries is 3.7V
  • The batteries are connected in parallel to
    provide peak current.

04-25-2007
18
AubieSat-I Design Review, Spring 2007
19
Battery Regulators
  • Each battery will be regulated by the Maxim 1879
    Li-Ion regulator.
  • The MAX1879 was selected for its over-voltage
    and temperature protection.
  • Also an easy to assemble, proven circuit.

04-25-2007
19
AubieSat-I Design Review, Spring 2007
20
3.3V/4.5V Voltage Regulator
  • The 3.3V and 4.5V regulated busses are provided
    by the MAX1705.
  • Multiple regulators are used to provide peak
    current and redundancy.
  • 3.3V is provided on LDO and 4.5V is on POUT as a
    by-product.

04-25-2007
20
AubieSat-I Design Review, Spring 2007
21
EPS Schematic 1
22
EPS Schematic 2
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