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 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.
connector | board | Signal | Pmod pin | FPGA pin |
---|---|---|---|---|
S1 bottom | power | USB TxD | J1.1 | 127 |
USB RxD | J1.3 | 124 | ||
LED 0 | J1.5 | 121 | ||
LED 1 | J1.7 | 118 | ||
S2 bottom | Computer On Module | COM RxD1 | J1.2 | 126 |
COM TxD1 | J1.4 | 123 | ||
COM GPIO 168 | J1.6 | 119 | ||
COM GPIO 167 | J1.8 | 117 | ||
S2 top | power | switch 0 | J3.2 | 133 |
switch 1 | J3.4 | 137 | ||
switch 2 | J3.6 | 139 | ||
switch 3 | J3.8 | 141 |
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.