Figure 677. Line Format Of Hard Reset; Figure 678. Line Format Of Cable Reset - ST STM32G4 Series Reference Manual

USB Type-C™ / USB Power Delivery interface (UCPD)
Packet format: Hard Reset (special case)
Among all ordered sets, the "Hard Reset" requires special treatment by the Physical Layer
hardware. This is due to the fact that this is a higher priority code and should directly
interrupt (in a clean manner) an on-going transfer.
The physical layer specification describes the behavior thus:
4. If the PHY Layer is currently sending a message, the message shall be interrupted by
sending an EOP K-code and the rest of the message discarded.
5. Wait tInterFrameGap.
6. If CC is not idle, wait for it to become idle
7. Send the Preamble followed by the 4 K-codes for Hard Reset signaling.
8. Disable the channel (i.e. stop sending and receiving), reset the PHY Layer and inform
the Protocol Layer that the PHY Layer has been reset.
9. Re-enable the channel when requested by the Protocol Layer
Packet format: Cable Reset
Cable Reset is similar in format to Hard Reset, but unlike Hard Reset it does not require a
specific high priority treatment.
The format is shown below in
2008/2083

Figure 677. Line format of Hard Reset

Preamble (training for receiver)
LEGEND:
Training sequence provided by the Physical
layer, not encoded with 4b5b
Figure 678

Figure 678. Line format of Cable Reset

Preamble (training for receiver)
LEGEND:
Training sequence provided by the Physical
layer, not encoded with 4b5b
RM0440 Rev 1
RST-1 RST-1 RST-1
Ordered set for
"Hard Reset"
Provided by the Physical layer,
encoded with 4b5b
RST-1 Sync-1 RST-1
Ordered set for
"Cable Reset"
Provided by the Physical layer,
encoded with 4b5b
RM0440
RST-2
MSv45540V1
Sync-3
MSv45541V1