USBPD EPR Request

[KamilB]

Hi! I'm working on a Power Delivery Sink using an STM32G484RETx MCU. I managed to get SPR Power Delivery working without any issues, but I'm having trouble handling the EPR handshake.

I'm using the latest USB-PD library from ST's GitHub:

https://github.com/STMicroelectronics/stm32-mw-usbpd-core

I can successfully enter EPR Mode, but the PD stack automatically calls Evaluate Capabilities and sends an SPR Request (Data Object[2] == 0). I can’t find any option to prevent the stack from running Evaluate Capabilities when Extended PDOs are received from the source.

I’ve read @FBL's post on the ST Community, which states that the latest stack should support EPR:

https://community.st.com/t5/stm32-mcus-embedded-software/update-about-usb-pd-stack-to-support-epr-mode/td-p/829168

Do you have any solutions or examples that show how to properly handle EPR using the ST USB-PD stack?

In the second screenshot, you can see that the stack incorrectly sends an EPR Request (Data Object[2] = 00000000h) because it still triggers the SPR Evaluate Capabilities callback.

Thanks.

[FBL]

Hi @KamilB 

Indeed, the stack supports it but we don't have an example to showcase the extended power range and the hardware supporting it.