USBD write

[Regio]

Hi,

I read data from FDS and output it to nRF USB. The output is implemented by

app_usbd_cdc_acm_write(&m_app_cdc_acm, m_tx_buffer, (sizeof(m_tx_buffer));

But I only see the last item on the output. Please, what is the problem so that I can see

the whole list on the terminals. The output via NRF_LOG_HEXDUMP_INFO is OK.

Best regards

Regio

[Edvin]

It is a bit difficult to say without knowing anything about your implementation of the fds or the usb. Perhaps you can share something?

Typical pitfalls:

FDS not done reading/writing before you use it. Wait for the callbacks.

How do you pass it to the usb?

[Regio]

Hi

app_usbd_cdc_acm_write from the sent code lists only the last item in the list. How to edit the code to list all items from the list?

[Dmitry]

Hi,

app_usbd_cdc_acm_write() has no internal buffering, you should wait for APP_USBD_CDC_ACM_USER_EVT_TX_DONE event after sending an item. 

[Regio]

Hi Dmitry,

thank you for your response.

if(new_usb_packet > 0 && usb_busy == false)
	   {
		   sprintf(&m_tx_buffer[12], "\r\n");
          
       app_usbd_cdc_acm_write(&m_app_cdc_acm,
                                 m_tx_buffer,      
                    (sizeof(read_data)*2)+2);      
 					
		      if(ret == NRF_ERROR_BUSY)
		      {
		      NRF_LOG_INFO("usb_busy = true");
		      usb_busy = true;
		      }
		      else if(ret != NRF_SUCCESS)
		      {
		      NRF_LOG_INFO("USB ret != NRF_SUCCESS");
		      }
		      else
		      {
		      new_usb_packet--;
          }
      }

I've already done that and it didn't help to see the code

[Dmitry]

if(ret == NRF_ERROR_BUSY)

where does your ret assigns something?

[Regio]

ret assigns 0

[Dmitry]

I mean, if you're going to check the result of app_usbd_cdc_acm_write(), there should be an assignment:

ret = app_usbd_cdc_acm_write(...)

Also it's hard to understand the complete logic of your code by these snippets, please post the whole code relevant to USB handling (cut out any app logic if there's something confidential).