CH340E configuration issue

[Mithun_K_Das]

I'm using CH340E USB to UART communication IC. Problem is, after power on, until any single bit of data is sent through PC terminal, no data is transmitting through the IC. MCU working fine. Once sending at least one bit of data from PC terminal, all communication works and data can be read on PC terminal which is coming from MCU via CH340E IC.

This works fine until power down. Once again while power on, need to send at least one data from PC terminal (Vertual terminal). Seems like until a data is sent from PC to the MCU, the CH340E IC is not getting the USB configuration. But once it gets the configuration, it works fine until power down.

MCU:STM32F407.

diagram is same as this.

Any suggestion to solve this?

 

[danadakk]

Use a script to send a byte and then start the application depending on it ?


Regards, Dana.

 

[Mithun_K_Das]

Is there any way to do that from the MCU side? where MCU is transmitting data through UART.

 

[danadakk]

That would be a function of the driver on PC side, not an expert here on this
but it must "listen" on its side depending on how it was written.

Try it ......


Regards, Dana.

 

[FvM]

Sounds rather unlikely, although not completely impossible. Are you sure that the issue is not in the uC firmware? Did you verify with an oscilloscope that the bridge IC is actually getting data but not sending it to USB. If so, it's probably a bug in CH340 silicon or USB driver software.