Algorithm-oriented heterogeneous hardware design has been one of the major driving forces for hardware improvement in the post-Moore’s Law era. To achieve the swift development of heterogeneous designs, designers reuse existing hardware components to craft their systems. However, current hardware design languages either require tremendous efforts to customize designs or sacrifice quality for simplicity. Chisel, while attracting more users for its capability to easily reconfigure designs, lacks a few key features to further expedite the heterogeneous design flow. In this paper, we introduce Twine—a Chisel extension that provides high-level semantics to efficiently generate heterogeneous designs. Twine standardizes the interface for better reusability and supports control-free specification with flexible data type conversion, which saves designers from the busy-work of interconnecting modules. Our results show that Twine provides a smooth on-boarding experience for hardware designers, considerably improves reusability, and reduces design complexity for heterogeneous designs while maintaining high design quality.