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= On-Board Computer (OBC) = | = 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 [https://www.epflspacecraftteam.com/chess-1 CHESS mission], | ||
+ | it communicates: | ||
+ | * with the EPS through [[OBC/CAN|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 | ||
= Attitude Determination and Control System (ADCS) = | = Attitude Determination and Control System (ADCS) = |
Revision as of 11:55, 18 September 2020
Contents |
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
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.
Register | Hex | Parameter | Description |
---|---|---|---|
BRGCON1 | 0x0F | BRP | (2x16)/FOSC |
SJW | 1 x TQ | ||
BRGCON2 | 0xBC | PRSEG | 5 x TQ |
SAM | once at sample point | ||
SEG1PH | 8 x TQ | ||
SEG2PHTS | Freely programmable | ||
BRGCON3 | 0x01 | SEG2PH | 2 x TQ |
WAKDIS | Enable CAN wake-up | ||
WAKFIL | CAN line filter not used |