The SILICA Xynergy-M4 Board combines an ARM Cortex-M4 based STMicroelectronics STM32F417 controller with a Xilinx Spartan-6 low-cost FPGA (XC6SLX16) in one design.
There are numerous development tools for either ARM Cortex-M microcontrollers or FPGA kits, but this is the first module in the market that merges both technologies on one board, although it is absolutely common to have a microcontroller next to an FPGA, performing tasks that cannot be integrated in the FPGA in a cost-effective way.
High costs for the adequate IP cores and for the additionally needed resources in the FPGA very often require an implementation in favor of a two-chip solution. Particularly the use of standard communication interfaces like Ethernet, USB and CAN are in most cases cheaper and easier to implement on a microcontroller.