Physical Layer Protocol; Table 233. 4B5B Symbol Encoding Table - ST STM32G0 1 Series Reference Manual

USB Type-C™ / USB Power Delivery interface (UCPD)
38.4.3

Physical layer protocol

The physical layer covers the signaling underlying the USB Power Delivery specification.
On the transmitter side its main function is to form packets according to the defined packet
format including generally:
•
preamble
•
start of packet (SOP, ordered set)
•
payload header
•
payload data
•
cyclic redundancy check (CRC) information
•
end of packet (EOP)
Before going on the CC line, the data stream is BMC-encoded, respecting specified timing
restrictions.
On the receive side, the principle task is to:
•
extract start of packet (SOP, ordered set) information
•
extract payload header
•
extract payload data
•
receive and check CRC
•
receive end of packet (EOP)
The receive is basically a reverse of the transmit process, thus starting with BMC data
stream decoding.
Symbol encoding
Apart from the preamble all symbols are encoded with a 4b5b scheme according to the
specification shown in the following table.
Name
1312/1390

Table 233. 4b5b Symbol Encoding Table

4b
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001
A 1010
B 1011
C 1100
5b
11110
01001
10100
10101
01010
01011
01110
01111
10010
10011
10110
10111
11010
RM0444 Rev 5
RM0444
Symbol description
hex data 0
hex data 1
hex data 2
hex data 3
hex data 4
hex data 5
hex data 6
hex data 7
hex data 8
hex data 9
hex data A
hex data B
hex data C