Custom systems-on-chips have been a good alternative for those who can afford the time and cost required for a gate array or cell-based ASIC design. A custom design offers the benefits of increased system integration and higher performance, but comes with high cost, long design cycles, and significant risk. As device geometries continue to shrink, and ASIC design costs continue to grow, fewer and fewer applications can justify the expense of a full-custom design.

With the advent of low-cost FPGA families, in which you can implement one or more embedded processors, custom embedded solutions are now viable for cost-sensitive applications and are well within the reach of the average embedded developer. Examining the possibilities that this relatively new embedded methodology offers lets you understand the benefits and tradeoffs.