USB device disconnect and connect in STM32L0

kevin239955_stm1_st · ‎2015-12-29

Posted on December 29, 2014 at 17:02

Hi

I just begin in STM32L0. I using my board for dev an USB example base STM32L053R8.

And I have a confused about USB connect and disconnect. I run a test case based on STM32L053R8_NUCLEO_USB for test. And I don't want USB host detect USB device till I call function USBD_Start at the code below. But the Host still detect my USB device. I have check the bit DPPU (BCDR register). It is still disable. I can not Image what is the reason

/* Init Device Library */

USBD_Init(&USBD_Device, &HID_Desc, 0);

/* Register the HID class */

USBD_RegisterClass(&USBD_Device, &USBD_HID);

while (1);

/* Start Device Process */

USBD_Start(&USBD_Device);

Thank for help.

Kevin

#stm32l0-usb-disconnect-connect

tsuneo · ‎2015-12-30

Posted on December 30, 2014 at 15:52

Likely, you are working on STM32Cube_FW_L0_V1.1.0?

And then, the stack code doesn't enable on-chip pull-up resistor until USBD_Start() is called.

Does your ''dev board'' have an external fixed pull-up?

Tsuneo