Uploading code to aTmega328 using Bluetooth on software serial

Amro93 · January 6, 2019, 3:05am

I 'm working on an ROV and I' m using RS485 with ROS to communicate my laptop with the arduino uno on the ROV. My problem is that I want to use hc-05 BT module to upload code to the arduino using software serial, because I can't use hardware serial as ROS uses it. Is that possible or is there a way to get ROS working on software serial?
Thanks in advance!

pert · January 6, 2019, 4:47am

There is a SOFT_UART option in optiboot for bit banged software UART:

github.com

Optiboot/optiboot/blob/e5c412b073887930125dfe48f82f64915bab7ed8/Wiki/CompilingOptiboot.md#compile-options

# Introduction #

You can compile Optiboot for platforms that do not have pre-existing .hex files, or you can make modifications to the source code and/or Makefile in order to implement "custom" versions of Optiboot.

This will require some relatively deep knowledge of avr-gcc, Atmel AVR hardware and processor details, Makefiles, and the command line environment.  We HAVE tried to take steps to allow Optiboot to be compiled without installing a full AVR development suite.


# Details #

Optiboot is designed to be compiled with the same version of avr-gcc that is distributed with the Arduino environment: 4.3.2.  This is actually quite an old version of gcc; some effort has been made to allow the compile to procede with new versions of the compiler.  However, since Optiboot MUST compile to a total size of less than 512 bytes, it is very sensitive to changes in the way the compiler does optimizations, or the way it processes optimization options on the compile command.

In all cases, Optiboot compiles directly from the command line using "make", rather than from within any IDE.  It is currently designed to used compilers installed in one of three different places:

  * Local Development Environment - you have WinAVR (on Windows), CrossPack (on Mac), or an avr-gcc package (linux) installed on your system, with appropriate development tools somewhere in your path.
  * You have Arduino installed, and are trying to compile Optiboot from its home directory within the Arduino directory structure (hardware/arduino/bootloaders/optiboot/)  The Arduino app includes a pretty complete set of compiler tools, and these can be used to compile optiboot without installing a separate toolchain. (as of Version 1.5 of the Arduino IDE, a much smaller set of tools is included, and this method doesn't work any more.)
  * You have downloaded the Arduino Source code, which also includes (binary) copies of avr-gcc toolchains, and a source directory containing the Optiboot source code.

WARNING: some targets don't compile with "make" 3.81 or 3.82 due to bug in it.  See https://github.com/Optiboot/optiboot/issues/106

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I don't have any experience with it.

You'd need to send a signal to start the bootloader before starting the upload. Usually a hardware reset is done. optiboot is written to jump right to the application after a watchdog reset, but it should be possible to modify it to also run on a watchdog reset.

I know some recent work has been done to enable OTA flashing from the application using the new flash write feature of Optiboot. That requires your sketch to only use 1/2 the flash memory of the Arduino. There's information here, and in the linked thread. Juraj also has an OTA library, but it says it only supports microcontrollers with least 64 kB of flash (your Uno has 32):

Amro93:
there is a way to get ROS working on software serial?

I don't know. What is the problem preventing it from working with software serial?

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Uploading code to aTmega328 using Bluetooth on software serial

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