Is it normal for the CTS line to always go low after debug starts?

[hi118]

After checking the UART waveform by running the sample "ble_wifi_onbording" that comes with "STM32 Connectivity Expansion Pack 1.1.0", I have a question.

Is it normal for the CTS line to always go low after debug starts?

The CTS line is always low, even if the TX and RX lines are moving.

If this was an anomaly, what do you think caused it?

I checked the waveform between STM32H747 Disco Kit and uRata uSD-M2 Adapter.

<Device>
・STM32H747I-DISCO
　STM32H747I-DISCO STMicroelectronics | Mouser
・LBEE0ZZ1WE-TEMP
　LBEE0ZZ1WE-TEMP Murata Electronics | Mouser
・Wi-Fi/BT module: 1DX M.2 Module
　1LV M.2 Module - Embedded Artists

[BragadeeshV]

Hi @hi118 ,

Could you please clarify if this behavior is observed in the CTS of the host or the wireless module?

[Charles_Lai · Accepted solution]

Hi,

If flow control is not enabled, CTS/RTS won't work.

Best regards