Q: What is the speed grade of the XC6SLX45 FPGA on the Digilent Atlys development board?

date:16 June, 2011

A: According to the information provided in the Atlys Base System Builder support file, the FPGA part number is XC6SLX45-3CSG324C, which means its speed grade is -3.

However, in the board schematics, the FPGA is identified as XC6SLX45-2CSG324C, which would mean its speed grade is -2.

I think it’s not unlikely that Digilent used both grades in their boards and are not even sure themselves :) Probably the best engineering practice would be to hope for the worst and design for -2 grade.

Here is the quote from BSB:

The Atlys board features a Xilinx Spartan-6 XC6SLX45-3CSG324C FPGA device, two input and two output HDMI ports, 1Gb (x16) DDR2 DRAM component for use with Spartan-6, 128Mbit Numonyx N25Q 128(x4) SPI Flash memory, Marvell Alaska 10/100/1000 PHY device (88E111) with GMII interface, HID Host for USB mouse, keyboard, USB-UART bridge for the serial port, AC 97 Codec with color coded jacks, 8 slide switches, 5 pushbuttons in “Gamepad” configuration, 8 LEDs and 1 reset button

The picture below shows what the digits in the part number mean.


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