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(On-Board Computer (OBC))
(PIC18LF26K83)
 
Line 22: Line 22:
  
 
= Attitude Determination and Control System (ADCS) =
 
= Attitude Determination and Control System (ADCS) =
 
=PIC18LF26K83=
 
==Configuration==
 
Clock is set to the highest value (64MHz) as the board is made for test purposes. It could be lowered if a such speed is not needed for the final use. Typically in order to reduce power consumption
 
 
Note that if done so, some parameters may need to be changed
 
===CAN===
 
As described in the ADCS control document, the CAN configuration is the following :
 
version 2.0 B, extended ID, SP set to 87.5% and SJW = 1, bus speed 125 kbps.
 
 
{|class=wikitable
 
|-
 
! Register || Hex  || Parameter || Description
 
|-
 
|rowspan="2"| BRGCON1
 
|rowspan="2"| 0x0F
 
| BRP || (2x16)/FOSC
 
|-
 
| SJW || 1 x TQ
 
|-
 
|rowspan="4"| BRGCON2
 
|rowspan="4"| 0xBC
 
| PRSEG || 5 x TQ
 
|-
 
| SAM || once at sample point
 
|-
 
| SEG1PH || 8 x TQ
 
|-
 
| SEG2PHTS || Freely programmable
 
|-
 
|rowspan="3"| BRGCON3
 
|rowspan="3"| 0x01
 
| SEG2PH || 2 x TQ
 
|-
 
| WAKDIS || Enable CAN wake-up
 
|-
 
| WAKFIL || CAN line filter not used
 
|-
 
|}
 
 
===UART===
 
 
===SPI===
 
 
===ADC===
 

Latest revision as of 11:01, 18 September 2020

CHESS mission

The CHESS mission wants to fly 2 Cubesats with primary mission to measure the earth’s atmosphere with the help of a mass spectrometer.

On-Board Computer (OBC)

The On-Board Computer (OBC) transfers information between the subsystems, mainly from the radio to mission payload and back.

In the CHESS mission, it communicates:

  • with the EPS through OBC/CAN
  • with the ADCS through a serial link
  • with the radios through a SPI link
  • with the mass spectrometer through a SPI link
  • with the GPS board through a SPI link

The data processing is distributed between a microprocessor and a FPGA logic. Additionally, a OBC/PIC PIC microcontroller bridges the FPGA to the OBC/CAN bus.

Attitude Determination and Control System (ADCS)

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