Hdlc Data Encoding/Decoding - Samsung S3C2500B User Manual

HDLC CONTROLLER

8.5.2 HDLC DATA ENCODING/DECODING

Data encoding is utilized to allow the transmission of clock and data information over the same medium. This
saves the need to transmit clocks and data over a separate medium as would normally be required for
synchronous data. The HDLC provides four different data encoding methods, selected by bits in HCON1[18:16].
An example of these four encoding methods is shown in figure 8-5.
Data 1
NRZ
NRZI
FM1
(Biphase Mark)
FM0
(Biphase Space)
Manchester
NRZ, NRZI Type
TxClock
Data
RxClock
FM0/FM1/
Manchester type
TxClock
Data
RxClock
8-12
1 0
Figure 8-5. Data Encoding Methods and Timing Diagrams
0 1
S3C2500B
0 Bit Cell Level:
High = 1
Low = 0
No Change = 1
Change = 0
Bit Center Transition:
Transition = 1
No Transition = 0
No Transition = 1
Transition = 0
High Low = 1
Low High = 0