DINO Peer Review 29 October 2015 Command and Data Handling Li, Michael Jayaraman, Vijay Bhatia, Vishal Winkelman, Martin.

DINO Peer Review April 20, 2023

Command and Data Handling

Li, Michael

Jayaraman, Vijay

Bhatia, Vishal

Winkelman, Martin

Colorado Space Grant Consortium 2


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 Intel PXA255 Processor.



Design Requirements

• C&DH must not exceed 7 Watts.• Maximum ½ kg.• External watchdog timer.• External reset.• 3.8” x 3.6” x 4” minimum profile• Must run Linux• 32MB RAM minimum• 8MB FLASH minimum



Interfaces

Subsystem Requirements

COMM• 1 dedicated RS-232 serial port to TNC.• 1 RS-232 serial port to initialize radios.

Science Two USB ports for cameras.

ADCS 9 channel ADC (12-bit precision minimum)

Tip-Mass 1 RS-232 serial port for RF module.

Structures13 binary inputs to monitor states of certain deploymentmechanisms

Power 1 R-232 serial port

Thermal 32 channel ADC for thermistors

Software Kernel, BSP etc…



Arcom Viper

• PXA255 400Mhz CPU• SDRAM: 64M• FLASH: 16M• 256K Battery Backed SRAM• Real-Time Clock• Watchdog Timer• Interfaces:

– 2 USB v1.1– 5 Serial Ports– Compact Flash Drive Support– Ethernet: 10/100BaseT– JTAG– 8 GPIO– PC/104



Power Consumption

PartPower Consumption

(Watts)

Flight Computer 1.6

Wireless Interface 2.4

Miscellaneous Interfaces 1(max)

Total 5 (max)



Specifications (Viper overview)

Power Requirements:

• 1.6W @ + 5V only supply (typical)

• 200mW @ +5V (standby mode)

Operating Temperature:

• -20°C to +70°C

• -40°C to +85°C (extended)

Form Factor: PC104



Design Options

• MIP405

• RPXLITE

• VIPER



OPTIONS CONSIDERED

Option 1 : MIP405• Integrated embedded IBM PowerPC processor • 375 DMIPS at 266MHz or PPC405GPr with 608 DMIPS at 400MHz• Power consumption Typically < 5.0 Watts• Ethernet, USB and 128MB SDRAM

Pros• 128MB on-board soldered SDRAM (ECC support), up to 4MB on-board soldered

Flash. • SRAM, EPROM, Flash and Disk-On-Chip modules can be added for keeping a

redundant copy of the Flight Operating System as a back up in case of failure.

Cons• Higher power consumption. • Doesn’t come with pre-loaded version of RedBoot Linux !!



OPTIONS CONSIDERED

Option 2 : RPX Lite• Integrated single-board computer based on the Motorola MPC823 version.• Capable of providing the user with a bandwidth of up to 80MHz. • Mechanical specifications of the PC104 standard• 32, or 64 Mbytes SDRAM16• 2, 4, 8, or 16 Mbytes Flash• 0, 32, 128, 512 Kbytes NVRAM/RTC• SCC2 - 10BaseT (RJ-45) Ethernet port

Pros• The Dino team could get some help from the 3CS team as this has been

previously used in the 3CS project.

Cons• Processor speed – 80MHz. Much less compared to the Viper.• Cost Per Unit ~$900. Much more expensive compared to other SBCs.• Poor technical support.



Reasons For Design Decision

• Ultra Low power consumption of 1.6Watts. • Has most number of Serial ports as compared to the other boards.• Provides 8 General Purpose I/O pins with expansion possibilities.• Meets all interface and design requirements.• Good processing speed of 400MHz.• Low Cost – Only $400!!• Lead Time of around 1-2 Weeks.• As the board is pretty new, it would be easily available in the market

until Dec 2005.• Dr. Sam Siewert and his team of researchers from the ECE

department (CU) are using the same Viper board in their research. He would be a great source of information regarding Viper incase the C&DH team needs his advice



Other Unexplored Options

• EBC-C3 Winsystems SBC up to 700MHz via Eden processor.

• SAT-520PLUS Winsystems SBC featuring 133MHz processor.



Testing PlansUART TEST – TX/RX verified on a terminal

Ethernet controller test – try pinging an IP address on the same network and say one IP outside the network (proposed to be used when we run short of the serial ports esp. for debugging and loading code on to the board…)

RAM test – try writing all 0s and all 1s and read them back. Try writing alternate 1s and 0s and try reading back and verifying the data

Flash test – similar to the RAM test.

Test with the actual viper board. test with a potentiometer which varies the voltage to the A/D converter.

JTAG Interface can be used to troubleshoot system hangs



Testing Plans (cont.)

• Test individual I/O pins.• Test USB – Probe bus and detect cameras• Test FPGA - Assert certain pins, test schematic.• Radiation Tolerance tests (industry supported?)



Budget

Component QuantityUnit Price

Total Price

Flight Computer 2 $410.00 $820.00

Interface Board

However many fits on a sheet ~$200.00 ~$200.00

Board Support Software 1 $1000.00 $1000.00

A/D board 1 ~$100.00 ~$100.00

Total: ~$2000.00



System Block Diagram

Flight Com puter (Arcom V iper)

Intel 400 MHz PXA255 XScale

Current/VoltageMonitors for Mechanism

Deploym ent

PC/104 PC/104

ADCSSensors

InterfaceBoard

Therm alSensors

(~32)

A /D ConvertersPC/104 TTL D igital I/O

USB (2) Reset Serial Ports

FPG A(Reset Logic)

PowerSubsystem

Tip MassRF Module

Radio/TNC(2 COM)

Science(Cam eras)



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

• Built-in watchdog on Viper

• Reset decoder will be implemented in FPGA



Issues and Concerns

• Radiation Shielding (How much, what kind…)

• BSP Software Licensing

• Testing Platform (Development Kit?)

DINO Peer Review 29 October 2015 Command and Data Handling Li, Michael Jayaraman, Vijay Bhatia, Vishal Winkelman, Martin.

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