Hardware/CubeSat RPi
(→Board to board) |
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== Board to board == | == Board to board == | ||
− | The inter-board connection is a serial bus with | + | The inter-board connection is a serial bus with coaxial cables for Tx and Rx lines. |
These channels are duplified for reasons of security. | These channels are duplified for reasons of security. | ||
− | To this comes a 0 V and 5 V power supply. | + | To this comes a 0 V, a 3.3 V and 5 V power supply. |
− | The connection is done by | + | The connection is done by coaxial connectors on two board sides. |
− | + | ||
== Raspberry Pi to FPGA == | == Raspberry Pi to FPGA == |
Revision as of 14:33, 6 December 2019
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This board is to serve an easy to use demonstrator for a CubeSat On-Board Computer (OBC). It hosts a Raspberry Pi Zero and a Microsemi ProASIC3 M1A3PE3000-2FG484I FPGA.
Power supplies
The board is powered from a standard 5 V ± 5% (4.75 V to 5.25 V).
This power supply is used by:
- the Raspberry Pi which generates a 3.3 V for itself and for the FPGA I/O banks
- a DC/DC converter which generates a 1.5 V for the FPGA core
The FPGA is supplied with:
Name | function | voltage |
---|---|---|
GND | ground | 0 V |
GNDQ | quiet ground | 0 V |
VCOMPLA/B/C/D/E/F | PLL ground | 0 V |
VCC | core supply | 1.5 V |
VCCIBx | I/O supply | 3.3 V |
VMVx | quiet I/O supply | 3.3 V |
VCCPLA/B/C/D/E/F | PLL supply | 1.5 V |
VJTAG | JTAG supply | 3.3 V |
VPUMP | programming supply | 3.3 V |
Connectors
Board to board
The inter-board connection is a serial bus with coaxial cables for Tx and Rx lines. These channels are duplified for reasons of security. To this comes a 0 V, a 3.3 V and 5 V power supply.
The connection is done by coaxial connectors on two board sides.
Raspberry Pi to FPGA
All Raspberry Pi I/O lines are connected to the FPGA. xxx of them are connected to the FPGA programming lines.
Programming
The Raspberry Pi Zero loads its operating system from the SD card.
The FPGA can be programmed either from the JTAG connector or from the Raspberry Pi. One has to make sure that the lines on the Raspberry Pi connector are tri-stated when trying to program the FPGA.