USB CDC ACM Example Single Write

[Fabian]

Hello,

we are using the USB CDC ACM Example to set up a USB connection between the computer and the nRF-Chip. By pressing Press Button 1 a bunch of test data will be sent to the terminal program (after a short delay).

But how is it possible to set up a instantaneous data-transfer of a single data array (for example after a button was pressed). It seems like the data are only transmitted after multiple callings of the function app_usbd_cdc_acm

Setup: nRF5 SDK v13.0.0 USB CDC ACM Example; nRF52840-Preview-DK

With kind regards

Fabian

[Jørgen Holmefjord]

Please check if this suggestion solves your problem.

[Deepa Gopinath]

Hi all,

I too face the same issue.

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.

Can you please help to resolve this issue?

Thanks in Advance

Regards,

Deepa

[Jørgen Holmefjord]

Hi, please post a new thread where you described your issue in detail. Please also include which SDK version you are using. If you are not using latest SDK, please see if you can get it working using SDK 15.0.0.