ST STM32G0 1 Series Reference Manual page 1324

USB Type-C™ / USB Power Delivery interface (UCPD)
The CCENABLE[1:0] bitfield can disable pull-up/pull-downs on one of the CC lines.
Note: The Type-C state machine depends not only on CC line levels, but also on VBUS presence
detection (sink mode) and when in source mode determines VCONN generation and VBUS
state (ON/OFF/+voltage level); discharge). UCPD does not directly control VBUS
generation circuitry nor VCONN load switch (enabling VCONN supply generator to be
connected to the CC line), but the application needs these inputs and controls to function
correctly.
General programming sequence (with UCPD configured then enabled)
1. Set ANAMODE and ANASUBMODE[1:0] based on the current position in USB Type-C
state machine (and also the current advertisement in the case of a source). This turns
on the appropriate pull-ups/pull-downs on the CC lines, and define the voltage levels
that the TYPEC_VSTATE fields represent. Note that before programming the PHY is
effectively off
2. Read TYPEC_VSTATE_CC1/2 to determine the initial Type-C state (for example
whether the local source is connected to a remote sink)
3. In the case of no connection then wait for a connection event
4. Assuming a connection is detected and assuming a local Power Delivery functionality
is implemented, start sending/receiving Power Delivery messages
5. When a new interrupt/event occurs on PHYEVT1/2 indicating a change in stable
voltage, re-evaluate the implications and give this input to the Type-C state machine
Case of a source that needs to change between one of the three possible Rp values
(Default-USB / 1.5A / 3.0A) and the sink connected to it:
•
[Source] Simply reprogram ANASUBMODE[1:0]
•
[Sink behaviour from that time] PHYEVT1/2 occurs and the TYPEC_VSTATE1/2
changes accordingly
Programming for a dual-role port (DRP) toggling from source to sink:
•
Simply re-program ANAMODE and ANASUBMODE[1:0] to start the new behavior
Detailed programming sequence (example):
1324/1390 RM0444 Rev 5
RM0444