USB Type-C™ / USB Power Delivery interface (UCPD) RM0440
2048/2126 RM0440 Rev 4
Ordered sets
An ordered set consists of four K-codes as shown in the following figure.
Figure 675. K-code transmission
The following table lists the defined ordered sets, including all possible SOP* sequences.
At the physical layer, the Hard Reset has higher priority than the other ordered sets so it can
interrupt an on-going Tx message.
On reception, the physical layer must accept ordered sets with any combination of three
correct K-codes out of four, as shown in the following table:
Table 422. Ordered sets
Ordered set name K-code #1 K-code #2 K-code #3 K-code #4
SOP Sync-1 Sync-1 Sync-1 Sync-2
SOP’ Sync-1 Sync-1 Sync-3 Sync-3
SOP’’ Sync-1 Sync-3 Sync-1 Sync-3
Hard Reset RST-1 RST-1 RST-1 RST-2
Cable Reset RST-1 Sync-1 RST-1 Sync-3
SOP’_Debug Sync-1 RST-2 RST-2 Sync-3
SOP’’_Debug Sync-1 RST-2 Sync-3 Sync-2
Table 423. Validation of ordered sets
Status 1st code 2nd code 3rd code 4th code
Valid Corrupt K-code K-code K-code
Valid K-code Corrupt K-code K-code
MSv45537V1
K-code 4 K-code 3 K-code 2 K-code 1
Bit 1
Bit 0
Bit 2Bit 3
Transmit firstTransmit last
Transmit firstTransmit last
b4 b0
Bit 4