Hi,
I am using a NUCLEO-G474RE with the X-NUCLEO-SRC1M1 board.
I have created and configures the project according to https://wiki.st.com/stm32mcu/wiki/STM32StepByStep:Getting_started_with_USB-Power_Delivery_Source
I am monitoring the board with the UCPD Monitor, configured one 9V 3A PDO and connected a 9V 3A PSU.
My issue is that some devices (mobile phones) charge slowly, some dont charge at all and some charge at full speed.
The PD negotiation seems to work in all cases, the 9V is present at TP1 in all cases.
My suspicion is that the unused CC line (VCONN line) is not being powered by the board. I tried implementing the VCONN based on this post, but was unsuccessful:
https://community.st.com/t5/stm32-mcus-embedded-software/does-the-latest-stm-usb-pd-core-stack-support-electronically/td-p/220555
I have attached the Traces, a capture of the CC1/CC2 lines and my project. These are with a phone connected that does not charge at all. With other PD supplies, the phone charges without problems.
As I understand, the unused CC line being low indicates an e-marker cable, and therefore requires the source to drive this line with VCONN. This however never seems to happen. I am not sure whether this is causing charging issues with the phones or if its completely unrelated.
Is there a more recent procedure on how to manage VCONN? I read this resource, however it didnt include any actual instructions or explanations on how to implement the functionality:
https://community.st.com/t5/stm32-mcus/understanding-vconn-in-stm32-and-tcpp-usb-type-c-port-protection/ta-p/750267
Your help would be greatly appreciated.
Edit: I have tested with a cable that has an emarker, the previous cable likely does not contain one after all.
Falling back to 5V works, the phone will charge.
I have attached the trace2.txt and capture2.png accordingly. Same problem, the phone wont charge. Limitations of uploaded items forced me to put them each into a zip.
