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 SDRAM: 64M FLASH: 16M NVRAM: 128K Real-Time Clock Interfaces: –USB –RS-232 Serial –PCMCIA –Ethernet: 10BaseT –SPI, I2C …

Requirements SubsystemRequirements COMM 1 dedicated RS-232 serial port to TNC. 1 RS-232 serial port to radios. ScienceTwo USB ports for cameras. ADCSI2C interface (minimum). Tip-Mass b link between main satellite and tip-mass.

Power Consumption Part Power Consumption (Watts) Flight Computer3 Wireless Interface3 Miscellaneous Interfaces1(max) Total7(max)

USB RESETSMC1SMC2 I2CI2C PCMCIA General Purpose I/O Pins FLIGHT COMPUTER (5V, 1A) CPLD (5V, 150mA) USB Interface SCIENCE RS232 DRIVER (5V, 7mA) MULTIPLEXER (5V) RADIO TNC COMM EPS ADCS Multiple Wires Wireless INTERFACE BOARD TIP-MASS RS232 Serial b (5V, 1A) System Block Diagram THERMAL INTERFACE THERMAL

USB Interface +5V GND D+ D- Camera0 +5V GND D+ D- Camera1 MUXMUX D+ D- Select Vcc

Thermal Interface Sensors in different parts of DINO Temp. Sensor Flight Computer ADC Sensor select for temperature reading MUXMUX 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 PartCostDistributorLead Time RPX-Lite 823e $995 Embedded Planet A week CPLD~ $50TBDA week ADC~ $5Maxim3 days ResistorsFew centsFloorN/A Multiplexers~ $20TBD3 days

Test Plans ADC testing requires accompanying software. All other interface board functionality can be confirmed with logic analyzer and multimeters.

Issues and Concerns