User`s manual
RTD Embedded Technologies, Inc. | www.rtd.com   7  FPGA35S6 User’s Manual 
1 Introduction 
1.1  Product Overview 
The FPGA35S6 series of FPGA boards are designed to provide platform to create any digital I/O that is required for 
your application. It interfaces with the PCIe bus and features a Xilinx Spartan 6 FPGA with a 27 MHz oscillator and 
1Gb of DDR2 SDRAM. There 48 5V tolerant I/O and 40 3.3V tolerant high speed I/O. 
1.2  Board Features 
  Xilinx Spartan 6 System level features 
o  XC6SLX45T 
  43,661 Logic Cells 
  2,489 kb of internal RAM 
  116 18Kb (2088 Kb Max) Block RAM 
  401 kB Distributed RAM 
o  XC6SLX100T 
  101,261 Logic Cells 
  5,800 kb of internal RAM 
  268 18Kb (4,824 Kb Max) Block RAM 
  976 kB Distributed RAM 
o  RAM hierarchical memory: 
  Each block RAM has two independent ports 
  Programmable Data Width 
o  Integrated Endpoint block for PCI Express 
o  Integrated Memory Controller 
  1 Gb of DDR2 SDRAM 
  Supports access rates of up to 800Mb/s 
o  Dedicated carry logic for high-speed arithmetic 
o  Abundant logic resources with increased logic capacity 
  Optional shift register or distributed RAM support 
  Efficient 6-input LUTs 
  LUT with dual flip-flops 
o  Four dedicated DLLs for advanced clock control 
  Phase shift input clock by 0, 90, 180, 270 
  Multiply input clock by 2 to 32 
  Divide input clock by 1 to 32 
  Fully supported by Xilinx development system 
o  ISE WebPACK (free download from http://www.xilinx.com) 
o  ISE Design Suite 
  Digital I/O Connectors 
o  48 5 volt tolerant I/O with ESD protection 
o  40 3.3 volt tolerant high speed I/O with ESD protection 
  PCI Express Bus: 
o  PCIe/104 Universal Board 
  Interfaces with Type 1 or Type 2 bus 
  No re-population 
o  Provides 2.5 Gbps in each direction 
o  In-band interrupts and messages 
o  Message Signaled Interrupt (MSI) support 










