ChibiOS Free Embedded RTOS

Posted: **Thu Oct 23, 2014 2:42 am**

Hi there,

I am trying to transmit data using the HAL Serial over USB Driver on an STM32F4. I am watching the value of sdup->config->usbp->state in gdb and have found that the application is returning at line 158 of serial_usb.c as shown below because sdup->config->usbp->state is USB_READY not USB_ACTIVE as it should be (I did check that sdup->state == SDU_READY so that part is fine).

Code: Select all

  
/* If the USB driver is not in the appropriate state then transactions
     must not be started.*/
  if ((usbGetDriverStateI(sdup->config->usbp) != USB_ACTIVE) ||
      (sdup->state != SDU_READY))
    return;

Here is my usb setup function -- is there something I should be doing to make the state USB_ACTIVE rather than USB_READY after these steps? I pulled this and the configuration structures (edited for my board obviously) straight from the testhal example.

Code: Select all

void usb_setup(void) {
  /*
   * Initializes a serial-over-USB CDC driver.
   */
  sduObjectInit(&SDU1);
  sduStart(&SDU1, &serusbcfg);

  /*
   * Activates the USB driver and then the USB bus pull-up on D+.
   * Note, a delay is inserted in order to not have to disconnect the cable
   * after a reset.
   */
  usbDisconnectBus(serusbcfg.usbp);
  chThdSleepMilliseconds(1000);
  usbStart(serusbcfg.usbp, &usbcfg); 
  usbConnectBus(serusbcfg.usbp);
}

Thank you in advance!

Posted: **Thu Oct 23, 2014 2:55 am**

You need to wait for the USB to be active.

This is what I use in my usb threads before my while loop:
while(USBD1.state != USB_READY) chThdSleepMilliseconds(10);
while(SDU1.state != SDU_READY) chThdSleepMilliseconds(10); // (sduStart is in the main thread)

Posted: **Thu Oct 23, 2014 3:29 am**

Your code waits for the USB to be ready, not active, though - right? At the point in the code where it's returning, the states are USB_READY and SDU_READY when they should be USB_ACTIVE and SDU_READY.

Posted: **Thu Oct 23, 2014 8:23 pm**

Yes, my bad

It's actualy how it's supposed to work.
This code is in the notify functions, which are not supposed to work if the usb is inactive. (active = enumerated on the host)

Does your usb enumerates properly? You can you transmit any data?

Posted: **Thu Oct 23, 2014 9:51 pm**

The only code for USB before I attempt the chnWriteTimeout() is in that setup function I've posted here. I'm not able to transmit data because the usbp state is never changed from USB_READY to USB_ACTIVE. I'm wondering if I'm missing something that I should be doing after the usb_setup functions and before calling the usb_write function to bring the state to USB_ACTIVE before calling chnWriteTimeout()?

Posted: **Thu Oct 23, 2014 9:58 pm**

It all depends from the host, if the enumeration is done then you should see a new virtual USB serial port on your PC. BTW, you need a driver for windows or the enumeration is not completed.

Assuming the driver is your problem, you could install this: http://www.st.com/web/en/catalog/tools/ ... pe=keyword

If you start writing before the USB goes in the active state nothing bad happens, the data is queued but not transmitted until it becomes active.

Giovanni

ChibiOS Free Embedded RTOS

Serial over USB Transmit Problem, STM32F4

Serial over USB Transmit Problem, STM32F4

Re: Serial over USB Transmit Problem, STM32F4

Re: Serial over USB Transmit Problem, STM32F4

Re: Serial over USB Transmit Problem, STM32F4

Re: Serial over USB Transmit Problem, STM32F4

Re: Serial over USB Transmit Problem, STM32F4