Is there a way to avoid using DTR while using usbd_cdc_acm?

[guojf]

Hi：

My environment is: nRF5_SDK_17.1.0_ddde560,  keil, s113_nrf52_7.2.0_softdevice

When using usbd_cdc, I found that DTR must be set to start communication. Is there any way to not use DTR, because some software does not operate DTR.

Regards

[Vidar Berg]

Hi,

To remove the dependency on DTR I'm afraid you only option is to patch the USB implementation. There aren't exposed any configuration settings to disable it. 

Here are some other posts about this which I think may be relevant:

 nRF52 DK - USB CDC ACM Example not working with HTerm/Qt 

https://devzone.nordicsemi.com/f/nordic-q-a/34933/usb-cdc-acm-example-is-not-working-in-interrupt-mode/139887#139887 

Best regards,

Vidar 

[guojf]

Hi ，

Thanks for your suggestion, I have realized this function by changing the SDK code.
When USB is turned on,

setup_req_class_out 

will be called. Here,

p_cdc_acm_ctx->line_state |= APP_USBD_CDC_ACM_LINE_STATE_DTR|APP_USBD_CDC_ACM_LINE_STATE_RTS;

; can realize automatic opening of DTR. Although this may not be a good way, it can meet my needs.