How to connect STM32G071 (GP-Version) for USB Type-C PD charging (60W max.)

[DRH]

Hi,

I'm looking for an example schematic of a USB PD charger interface using STM32G071G8U. Current questions are:

• Is the available singe CC pad (PA8) all you need from the hardware point of view?
• Is there any option to connect D+ and D- to allow 5V loads to charge with higher power (DCP)?

Our plan is to switch from a autonomous USB PD charge IC to the STM32G071.

[Yohann M.]

Dear @DRH​ 

you need to have at least:

• 2 PIN for CC lines (PA8-UCPD1_CC1 and PB15- UCPD1_CC2) (in case of active cable like STM32G071B-DISCO board, you could connect only 1 PIN)
• 1 PIN for VBUS Sensing (done with ADC channel)

There are no USB instance on STM32G071G8U (D+/D- not available on this MCU)

Idea is to enable a SRC legacy type-C cable in STM32CubeMX V6.1.0 in using the library 'Type C with state machine' (5V only).

You have the choice to present different RpValues ('CAD default resistor' in 'Stack Port 0 parameters' from 'USBPD Mode and Configuration panel'):

• Default USB Power: max500mA
• USB Type-C current @1.5A
• USB Type-C current @3.0A

(function USBPDM1_AssertRp)

Regards,

Yohann

[DRH]

Hi @Yohann M.​ ,

Thank you very much. I didn't know about the legacy support of stm32 and have to check it. That sounds to be a good option.

Thank you as well for the feedback regarding USB Type-C. That means for a 60W USB Type-C source with passive cables I can't use the GP version of the STM32G071 because there is only one CC-Pin available? I understand that for active cables, one CC will be used as VCONN and therefore only the other is necessary. But I assume that for passive cables, only one CC is necessary as well? Is that wrong?

Regards,

[DRH]

Hi,

ok, I think my mistake in thinking is that passive cables only provide one CC wire and the other CC pins are not connected to each other. In this case, by twisting the cable a source with only one CC Pin will not work.

Is it an option to parallel both pins in the source to work with passive cables?

Please excuse, I'm a little confused because I have seen very much different circuits and solutions but don't know what approach is the universal one working with most sinks. Thanks again for your support.

[JDUMA]

​Hello, you can visit this web page showing a typical USB PD charger (27W) using STM32G0 : https://www.st.com/content/st_com/en/products/evaluation-tools/solution-evaluation-tools/psu-and-converter-solution-eval-boards/steval-usbpd27s.html#overview

I recommend also to have a check on our landing page for all USB-C solutions based on our MCUs : https://www.st.com/content/st_com/en/stm32-usb-c.html

Best regards, JP 

[Yohann M.]

Hi

Default option is to use both CC pins. This allows to work with any type-C cable.

STM32G0 is able to detect a sink or source device if it is configured in DRP mode (Dual Power Mode). If you want to work higher than 15W, you should use the Power Delivery protocol provided in our FW package (library should be selected accordingly).

I suggest you to have a look at the different linked provided by @JDUMA​.

Regards

Yohann

[DRH]

Hi All,

thank you for your support. That's exactly what I was looking for. One question to clarify: Is there an USB Type-C interface where it's possible to use the STM32G071 GP version with only one CC pin?

Regards,

DRH

[Yohann M.]

Dear @DRH​ 

On STM32G071B-DISCO board, only 1 CC pin is used but this is a specific use case.

Regards,

Yohann

[DRH]

Hi,

thank you for your response. For me it looks like the hardware provides both CC pins but I have to double-check the firmware. It's a special use case because it's a sniffer only, isn't it?

Regards,

DRH

[Yohann M. · Accepted solution]

The disco board is a sniffer but also a sink device which has an integrated cable. It is a plug and not a receptacle in which one we should determine the CC line used for PD connection. In this board, from HW point of view, one of the CC line of the STM32G0 is already connected and used for the PD connection (there is only 1 CC line a Type-C cable)

From Firmware side, it is able to determine automatically which CC line form the Type-C cable is connected.