HiRel/CanSat/Master FPGA
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This board will be the master board on the HiRel/CanSat.
System
The design contains a soft-core processor controlling the different slaves of the HiRel/CanSat via peripheral devices attached to it by an AHB-lite bus system.
Connections
The FPGA board hosts a 106.25 MHz oscillator and a button which can be used as a reset signal.
Signal | FPGA pin | FPGA dir |
---|---|---|
clock | 16 | in |
reset_n | 2 | in |
The FPGA board connectors consist of 4 dual Pmods, each having 12 pins. The Pmods are connected to the slave boards via the bottom and the top ring.
board | connector | Signal | Pmod pin | FPGA pin | FPGA dir |
---|---|---|---|---|---|
slave 1: power supply |
bottom | TxD | J2.1 | 14 | |
RxD | J2.3 | 11 | |||
LED 0 | J2.5 | 8 | out | ||
LED 1 | J2.7 | 5 | out | ||
top | switch 0 | J4.1 | 24 | in | |
switch 1 | J4.3 | 27 | in | ||
switch 2 | J4.5 | 32 | in | ||
switch 3 | J4.7 | 35 | in | ||
slave 2: XBee radio |
bottom | RxD | J2.2 | 15 | |
TxD | J2.4 | 12 | |||
reset | J2.6 | 9 | |||
sleep request | J2.8 | 6 | |||
top | RSSI PWM | J4.2 | 23 | ||
associate | J4.4 | 26 | |||
DIO | J4.6 | 30 | |||
sleep | J4.8 | 33 | |||
slave 3: Computer On Module |
bottom | RxD1 | J1.1 | 126 15 | |
TxD1 | J1.3 | 123 12 | |||
GPIO 168 | J1.5 | 119 9 | |||
GPIO 167 | J1.7 | 117 6 | |||
top | audio signals | ||||
slave 4: sensors |
bottom | CS_n | J1.2 | 126 14 | out |
MOSI | J1.4 | 123 11 | out | ||
MISO | J1.6 | 119 8 | in | ||
SClk | J1.8 | 117 5 | out | ||
top | int_n | J3.2 | 133 24 | ||
J3.4 | 27 | ||||
J3.6 | 32 | ||||
cnvt_n | J3.8 | 141 35 |
FPGA comparisons
The choice of the FPGA was based on a comparison of synthesis results of a simple AHB-Lite system.
Manufacturer | Device | Estimated Frequency | LUTs / CoreCells | Memory | ||
---|---|---|---|---|---|---|
[MHz] | % | Needed | Available | |||
Xilinx | XC6SLX9 | 75.3 | 807 | 13 | 4 | 32 |
Microsemi | AGL60 | 16.4 | 56896 | 3704 | 2 | 4 |
Microsemi | AGL250 |
As it is visible in the table above, the smaller Microsemi Igloo devices are too small for us. Bigger Microsemi Igloo devices however are not easily available and also quite expensive (>80$). On the other hand the Xilinx Spartan 6 FPGAs are quite spacious, immediately available and have a reasonable price (<20$). Furthermore we already use them successfully on our FPGArack board.