upload firmware over half duplex RS-485

Does the Arduino bootloader work in a half duplex manner? I have used the Arduino bootloader for my own personal projects with great success. I have a new project that has a “two-wire” (half-duplex) RS-485 serial interface. Once the board is in its housing, the ISP connector is difficult to access. I was wondering could I use the RS-485 interface to program the chip. I’m using the hardware UART of the chip for the RS-485 interface. The essence of my question is can the bootloader work in a half duplex manner.

Yes & no: Actual comms are half-duplex - the PC serial port sends stuff, the Arduino bootlaoder responds.
But you need to be able to trigger a reset to get the bootloader to kick off.
How will you accomplish that over RS485?

Thank you for answering my question. For the reset, I will just jerry-rig something up to cycle the power. That won’t be a problem. BTW, I’ll have to modify the bootloader to control the TX enable pin of the RS-485 transceiver which shouldn’t be a problem either. Thank you!

For the reset, I will just jerry-rig something up to cycle the power.

At exactly the right moment?

PaulS:
At exactly the right moment?

Its relatively easy to do. Heck you can even do it by pushing a reset button at the right moment (half a second or so). I have some chips with the reset pin disabled so the only way to bootload is to power cycle just before upload and it works fine.

Wondering if there has been any success in this area, I am currently looking into doing the same thing. programming over RS485 that is..
Thanks
Quentin

It worked for me.