HBLbits_Verilog Basic_Fsm hdlc
Synchronous HDLC framing involves decoding a continuous bit stream of data to look for bit patterns that indicate the beginning and end of frames (packets). Seeing exactly 6 consecutive 1s (i.e., 01111110) is a "flag" that indicate frame boundaries. To avoid the data stream from accidentally containing "flags", the sender inserts a zero after every 5 consecutive 1s which the receiver must detect and discard. We also need to signal an error if there are 7 or more consecutive 1s.
Create a finite state machine to recognize these three sequences:
Here are some example sequences that illustrate the desired operation.
Create a finite state machine to recognize these three sequences:
- 0111110: Signal a bit needs to be discarded (disc).
- 01111110: Flag the beginning/end of a frame (flag).
- 01111111...: Error (7 or more 1s) (err).
Here are some example sequences that illustrate the desired operation.
High-Level Data Link Control (HDLC) is a bit-oriented code-transparent synchronous data link layer protocol developed by the International Organization for Standardization (ISO). The standard for HDLC is ISO/IEC 13239:2002.
HDLC provides both connection-oriented and connectionless service.
HDLC can be used for point-to-multipoint connections via the original master-slave modes Normal Response Mode (NRM) and Asynchronous Response Mode (ARM), but they are now rarely used; it is now used almost exclusively to connect one device to another, using Asynchronous Balanced Mode (ABM).
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