Hardware/CubeSat Gumstix
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This board is the result of a diploma work. It is meant to be a first evaluation version of a Cubesat image processing board.
Type | FPGA Rack | Schematic | UCF | Description |
---|---|---|---|---|
2015 | ![]() |
FPGA + Gumstix 2015 schematic top view |
FPGA + Gumstix 2015 UCF | FPGAs: Spartan 6 XC6SLX45, XC6SLX100 or XC6SLX150 SPI flash: M23P64-ME |
Components
Camera
The camera interface connector is foreseen to be used with different camera models. The connector layout is:
pin | signal | function |
---|---|---|
1 | 3.3 V | 3.3 V |
2 | GND | GND |
3 | TxD / SCLK | RS232 / I2C control |
4 | RxD / SDA | |
5 | Frame valid / VSync | frame control |
6 | Line valid / HRef | |
7 | Data valid | |
8 | Pixel clock | |
9 | D0 | frame data |
10 | D1 | |
11 | D2 | |
12 | D3 | |
13 | D4 | |
14 | D5 | |
15 | D6 | |
16 | D7 | |
17 | D8 | |
18 | D9 | |
19 | D10 | |
20 | D11 | |
21 | CC1 / ExtSync | camera control |
22 | CC2 / XCLK | |
23 | CC3 / Reset | |
24 | CC4 / PowerDn |
ADC
The board hosts a ADS8028 12-bit, 1 MSPS, 8-channel analog-to-digital converter.
The ADC is powered with the input 5 V for the analog part and with a local 3.3 V for the digital lines. The voltage reference input connects to the analog power supply via jumper J5.
Inputs AIN0 to AIN4 are used to monitor the board's power supplies. Inputs AIN5 to AIN7 are sourced by connector J9.
The connection to the FPGA is given in the following table:
ADC signal |
FPGA pin |
function |
---|---|---|
CS_n | C16 | chip select, active low |
SCLK | B12 | serial clock |
DOUT | A18 | slave out (MISO) |
DIN | C17 | slave in (MOSI) |
PD_n_RST_n | B18 | power down or restart, active low |
BUSY | A17 | busy aquiring temperature |
Peripheral connectors
Two 24-pin peripheral connectors are provided. Both comprise 2 power supply pins and 22 FPGA I/O:
connector pin |
FPGA pin peripheral 1 |
FPGA pin peripheral 2 |
---|---|---|
1 | 3.3 V | 3.3 v |
2 | GND | GND |
3 | Y1 | L1 |
4 | Y2 | L3 |
5 | W1 | K1 |
6 | W3 | K3 |
7 | V1 | J1 |
8 | V3 | J3 |
9 | U1 | H1 |
10 | U3 | H3 |
11 | T2 | H2 |
12 | T4 | H4 |
13 | T1 | G1 |
14 | T3 | G4 |
15 | R1 | F1 |
16 | R4 | F3 |
17 | P1 | F2 |
18 | R3 | F5 |
19 | N1 | E1 |
20 | N3 | E3 |
21 | M2 | D1 |
22 | M4 | D3 |
23 | M1 | D2 |
24 | M3 | D5 |
Power supplies
The board receives a 5 V power input. 4 DC/DC converters provide power for different components.
FPGA supply
On the FPGA:
- VCC33 is used by the FPGA for VCCAUX, the SPI flash, the JTAG connector, bank 0 and bank 3
- VCC18/33 is used for FPGA bank 1
- VCC25/33 is used for FPGA bank 2
- VCC12 is used for the FPGA core
Bank 0 connects to the camera and the ADC
Bank 1 is connected to the Gumstix and 1.8 V should be used. The Gumstix board could be replaced by a memory board which might require 3.3 V signalling
Bank 2 connects to the On-Board Computer (OBC). The OBC connector B allows to have SpaceWire differential lines. If so, one has to mount the 165 Ω serial and 140 Ω parallel resistors. Normal CMOS signalling requires 0 Ω serial and no parallel resistors.
Bank 3 connects to the spare connectors on the side of the board.