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Jan "Yenya" Kasprzak edited this page Jul 31, 2020 · 3 revisions

FlySkyI6 Development

Toolchain

The firmware is compiled with arm-none-eabi GCC toolchain. Install gcc and binutils for arm-none-eabi on your system, as well as make.

Build using make

  • clone the FlySkyI6 repository
  • go to the source/build directory
  • run make all or make all-swe, depending on the firmware version you want to build (for an unmodified hardware or for Tx with added SwE switch)
  • The fs-i6_updater-MM-DD-HH-MI.bin or fs-i6-swe_updater-MM-DD-HH-MI.bin is the resuilting file for installing with mhils' updater utility.

Hacking the C code

Note that this is not a project written fully in C. It is just a bunch of C and ASM routines binary-patched to the original FlySky binary firmware.

The memory inside the MCU is very tight, and it might well be that the modification of C code will result in the new version of the binary code being too big for the dedicated space. In that case, you get the sections overlap error while linking.

In that case, you might want to modify the placement of the C routines in the final binary in the linking script source/MKL16Z64xxx4_flash.ld. Have a look at fs-i6.map or fs-i6-swe.map file in the source/build directory to obtain the sizes of varions code sections.

ASM

NOTE: this is a copy of the development.md file from the code repository

ASM compilation:

arm-none-eabi-as.exe -o fsi6.o fsi6.asm -mcpu=cortex-m0plus -mthumb -g3

arm-none-eabi-objcopy.exe -O binary fsi6.o fsi6.bin

Docummented disassembly can be found in ASM/10ch.0x0000

Documentation was created with use modified script

http://magiclantern.wikia.com/wiki/GPL_Tools/disasm.py

It is also to possibile to compile some parts of modifyed firmware with gcc (all c files are in source directory). The project was originally compiled with Freescale Kinetics.

Compiled elements must be replaced later in original file (addresses are described in source/MKL16Z64xxx4_flash.ld) Current linker script is not able to combine compilation results and old FW. Command used for compilation (extraced from Freescale Kinetics)

arm-none-eabi-gcc -mcpu=cortex-m0plus -mthumb -Os -fmessage-length=0 -fsigned-char -ffunction-sections -fdata-sections -Wall -g -D"CPU_MKL16Z64VLH4" -I../startup -I../board -I../utilities -I../CMSIS -I../drivers -std=gnu99 -MMD -MP -MF"source/file.d" -MT"source/file.o" -c -o "source/file.o" "../source/file.c"

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