The USB interface may interfere with the QVGA display on the STM32F429I-DISC1

[balaji_s]

In my program code, I select an STM32F429I-DISC1 example code through the TouchGFX IDE, which runs successfully in STM32F429I-DISC1 dev board. The displays work fine without any issues. However, I need to configure the USB CDC. Since the USB_OTG_FS pins are connected to the display, I enabled USB_OTG_HS with the following settings:

              1.PB14 set to USB_OTG_HS_DM

              2.PB15 set to USB_OTG_HS_DP

              3.Internal FS PHY set to "device only."

              4.USB device class set to "communication device class" for HS IP.

The output is received, but the display screens appear half-filled and continuously blink. The USB pins are not configured for any other operation, so why is there a conflict between the USB and the display?

[waclawek.jan]

Maybe bandwidth exhaustion?

JW

[GaetanGodart]

Hello @balaji_s ,

I have created a a project using the STM32F429I-Dk rev E01.
It worked fine.

Then I went on the IOC and enabled the USB_OTG_HS like you did but I did not find where to set USB device class to "communication device class" for HS IP.
It also worked fine.

I am not sure how to help you since I am unable to replicate the issue.

Have you selected the right TouchGFX Board Setup (TBS)? There is 2 TBS for this board, you have to take the correct one based on your board revision :

Regards,

[balaji_s]

Hello @GaetanGodart ,

I’ve set up my project configuration, and everything is functioning well until I enable the USB CDC.

When I drag the cursor over the USB_OTG_HS, the status shows as "partly disabled," and there is a conflict with the LTDC, where the display type is set to RGB565 (16-bit). Here are the steps I followed for configuration:

• I selected USB_OTG_HS with the Internal FS Phy set to Device Only.
• For USB_DEVICE, I chose Class For HS IP and set it to the Communication Device Class.

After completing all the configuration steps and generating the code, I started receiving data from the USB. However, the display flickers or blinks intermittently, with only half of the display functioning correctly.