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Command and Data Handling. Yousef Alyousef Michael Li. Introduction. Command and Data Handling subsystem is responsible for computing and control of subsystem functions. The core of this subsystem is a single-board computer powered by the Motorola PowerPC 823e from Embedded Planet. RPX Lite. - PowerPoint PPT Presentation
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Command and Data Handling
Yousef AlyousefMichael Li
Introduction
• Command and Data Handling subsystem is responsible for computing and control of subsystem functions.
• The core of this subsystem is a single-board computer powered by the Motorola PowerPC 823e from Embedded Planet.
RPX Lite
• SDRAM: 64M
• FLASH: 16M
• NVRAM: 128K
• Real-Time Clock
• Interfaces:– USB
– RS-232 Serial
– PCMCIA
– Ethernet: 10BaseT
– SPI, I2C …
Requirements
Subsystem Requirements
COMM
•1 dedicated RS-232 serial port to TNC.•1 RS-232 serial port to radios.
Science Two USB ports for cameras.
ADCS I2C interface (minimum).
Tip-Mass802.11b link between main satellite and tip-mass.
Power Consumption
PartPower Consumption
(Watts)
Flight Computer 3
Wireless Interface 3
Miscellaneous Interfaces 1(max)
Total 7(max)
USB RESET SMC1 SMC2 I2C PCMCIA
General Purpose I/O Pins
FLIGHT COMPUTER (5V, 1A)
CPLDCPLD
(5V, 150mA)
USB
Interface
SCIENCERS232 DRIVER
(5V, 7mA)
MULTIPLEXER
(5V)
RADIO TNC
COMM
EPS ADCS
Multiple Wires
Wireless
INTERFACE BOARD
TIP-MASS
RS232 Serial
802.11b(5V, 1A)
System Block Diagram
THERMALINTERFACE
THERMAL
USB Interface
+5V
GND
D+
D-
Camera0
+5V
GND
D+
D-
Camera1
MUX
D+
D-
SelectVcc
Thermal Interface
Sensors in different parts of DINO
Temp. Sensor
Flight Computer
ADC
Sensor select for temperature reading
MUX
Digital Temp. readings
select
Temp. Sensor
+5V
10k
Temperature Sensors
Temperature-controlled Variable Resistor
Voltage proportional to temperature change
Watchdog and Reset Decoder
• These will be implemented in CPLD
Parts List
Part Cost Distributor Lead Time
RPX-Lite 823e
$995Embedded
PlanetA week
CPLD ~ $50 TBD A week
ADC ~ $5 Maxim 3 days
Resistors Few cents Floor N/A
Multiplexers ~ $20 TBD 3 days
Test Plans
• ADC testing requires accompanying software.
• All other interface board functionality can be confirmed with logic analyzer and multimeters.
Issues and Concerns