USB CDC ACM Flushing Write Data

[Deepa Gopinath]

Hi all,

In our program calling app_usbd_cdc_acm_write() a single time does not directly send a message to the terminal program (Teraterm). 
Even Teraterm is not getting connected to USB Port.Even though an APP_USBD_CDC_ACM_USER_EVT_TX_DONE is generated and the LED4 is changing its status. 
After calling app_usbd_cdc_acm_write() the fourth time all four messages (the current one and the three from before) are visible on the computer.

I have observed this behaviour when Im in debug mode. But When I do free run , messages are not visible on the computer after 4th message.
In case of free run messages are visible on the computer after 20th message.

Nordic SDK - nRF5_SDK_14.2.0_17b948a

Can you please help to resolve this issue?

Thanks in Advance

Regards,

Deepa

[Deepa Gopinath]

Hi all,

I have observed the same behaviour on nRF5_SDK_15.0.0_a53641a also

Can you please help to resolve this issue?

Thanks in Advance!!

Regards,

Deepa

[Sigurd]

Hi,

What is the size of the packets you are sending? Could you try to send an empty packet and/or a 32bit packet as the last packet. Let me know if that doesn’t work.