Reasons for USB-UART Component Enumeration Failure – KBA90556

[Anonymous]

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Translation - Japanese: USB-UART コンポーネントの エニュメレーションが失敗する原因 - KBA90556 - Community Translated (JA)

Question:

What are the possible reasons for the USB-UART component failing to enumerate?

Answer:

The USB_UART component fails to enumerate if there is a mismatch between the V_DDD supplied on the board and V_DDD voltage settings in the PSoC® Creator™. You must ensure that these values match. You can check the value for your project in PSoC Creator as shown in the figure below.

Figure 1. V_DDD Setting in the .cydwr Tab

In addition, you must ensure that in the USBFS_Start(uint8 device, uint8 mode) and USBFS_InitComponent(uint8 device, uint8 mode) APIs, the value to the argument uint8 mode matches the V_DDD used in the design. USBFS_Start() API activates the component in specific voltage mode and USBFS_InitComponent() API This function initializes the component’s global variables and initiates communication with the host by pull-up D+ line. Please refer the USBUART component datasheet for more details of the APIs.