HDLC & SDLC Protocol Controller

The HSDLC IP core implements a controller for the High-Level Data Link Control (HDLC) and the Synchronous Data Link Control (SDLC) protocols. It is based on the Intel 8XC152 Global Serial Channel (GSC) working in SDLC mode, and adds features to support HDLC or proprietary frame transmission under host processor control.

The core operates as a peripheral to a host processor, and is easy to integrate with both modern and legacy processors. Control and status registers are accessible via an APB or a generic 80c51-like bus interface, and a comprehensive set of interrupt signals facilitates interrupt-based operation.


The controller’s great flexibility enables a variety of serial link setups. It provides two independent interfaces, one for transmitting and one for receiving data. Both interfaces provide control signals for the link drivers to support both full- and half-duplex operation. The controller can be programmed to use hardware flow control signals (RTS/CTS) and it can also detect collisions. The baud-rate is programmable and limited only by the link drivers and the core’s clock frequency. The core derives the receive clock from the received serial data, or uses an externally provided receive clock.

The HSDLC controller core is designed for reuse and is rigorously verified and scan-ready. Although designed to manage serial links, the core contains no latches or tri-states, and is fully synchronous with a single clock domain. The core is available in Verilog RTL or as a targeted FPGA netlist. Deliverables provide everything required for a successful implementation, including sample scripts, an extensive testbench, and comprehensive documentation.