Xilinx Virtex-6 Libraries Guide for HDL Designs

Chapter 4: About Design ElementsCFGLUT5Primitive: 5-input Dynamically Reconfigurable Look-Up Table (LUT)IntroductionThis element is a runtime, dynamically reconfigurable, 5-input look-up table (LUT) that enables the changingof the logical function of the LUT during circuit operation. Using the CDI pin, a new INIT value can besynchronously shifted in serially to change the logical function. The O6 output pin produces the logical outputfunction, based on the current INIT value loaded into the LUT and the currently selected I0-I4 input pins.Optionally, you can use the O5 output in combination with the O6 output to create two individual 4-inputfunctions sharing the same inputs or a 5-input function and a 4-input function that uses a subset of the 5-inputlogic (see tables below). This component occupies one of the four 6-LUT components within a slice.To cascade this element, connect the CDO pin from each element to the CDI input of the next element. This willallow a single serial chain of data (32-bits per LUT) to reconfigure multiple LUTs.Port DescriptionsPort Direction Width FunctionO6 Output 1 5-LUT outputO5 Output 1 4-LUT outputI0, I1, I2, I3, I4 Input 1 LUT inputsCDO Output 1 Reconfiguration data cascaded output (optionally connect to the CDI inputof a subsequent LUT)CDI Input 1 Reconfiguration data serial inputCLK Input 1 Reconfiguration clockCE Input 1 Active high reconfiguration clock enableVirtex-6 Libraries Guide for HDL Designs114 www.xilinx.com UG623 (v 11.4) December 2, 2009