STM32F103 internal bootloader work on RS485?

[Jian Chen]

Posted on October 25, 2017 at 16:32

Hi,

I am using STM32F103RET6 microcontroller. On my PCB, the USART1 channel is used as RS485 communication with a SN65HVD11HD transceiver.  That means to transmit/receive each character, the direction pins RE, DE pin of the transceiver has to be controlled.  Can I still use the internal bootloader inside the micro developed by ST? 

If I cannot, is there an example about how to develop the bootloader myself?

Thanks, Jian

[Tesla DeLorean]

Posted on October 25, 2017 at 17:07

The built in loader isn't going to work very well for you, and it isn't particularly feature rich anyhow.

Boot-loaders are a staple of embedded development, sure there is plenty of material out there to be consumed.

http://shop.oreilly.com/product/0636920017776.do

 

ST has some IAP example code using a variety of interfaces. For serial my preference is X-MODEM, being small, robust and having its own flow control, plus a wealth of cross-platform terminal support.

There might be some protocols more appropriate to RS485, or other half-duplex channels. If you have to own the app development at both ends construct something that meets your needs.