Update readme.md

firmware/bootloader/readme.md

@@ -1,54 +1,5 @@
 # Bootloader
 
-### BIG OPEN QUESTION: do we need to merge this custom BL into OpenBLT? See https://github.com/rusefi/rusefi/wiki/Firmware-update-via-CAN
+See https://github.com/rusefi/rusefi/wiki/Firmware-update-via-CAN
 
-*** User Manual ***
-
-To start the bootloader updater:
-- Turn off your rusEFI ECU board, and connect UART to PC.
-- Download "FLASHER-STM32" here: http://www.st.com/en/development-tools/flasher-stm32.html
-- Run "STMFlashLoader Demo", set COM-port parameters (the same as in TunerStudio).
-- Press the "Next" button.
-- Turn on the ECU board.
-- If the connection is successful, the next page of STMFlashLoader appears immediately. Press "Next" button again and follow the instructions.
-- You can use:
-  - Upload from device (Flash Read) command;
-  - Download to device (Flash Write) command;
-  - Erase->Selection command (only Sector erase is currently supported, not Full Erase!).
-
-To update the firmware:
-- choose "Download to device" mode;
-- select the firmware file (rusefi.hex). Note! ***Use only recent firmware builds with bootloader support!***
-- you may select "verify" option to check 
-- you may select "Jump to the user program" to automatically run the main firmware after the update.
-
-![image](STMFlashLoader_all_screenshots.png)
-
-!!! Note that the bootloader can update only the main firmware, but not itself !!!
-
-Use this code on your own risk!
-
-
-*** Developers Section ***
-
-Problem statement:
- - UART + bluetooth bootloader for Prometheus board which does not have USB
- - future plan: firmware from SD card
- - future plan: some sort of settings reset mechanism
-
-How it works, in two words:
-- The bootloader requires a separate makefile because it's a separate binary executable with its own project settings and fileset.
-- Start firmware/bootloader/compile_bootloader.bat to compile the bootloader code. Use it only if bootloader modification is required.
-- The compiled bootloader code is stored in bootloader/bootloader_generated.hxx and it can be included into the main firmware (build/rusefi.hex) if the bootloader support is enabled.
-- The bootloader support is disabled by default (USE_BOOTLOADER=no). You can enable it by adding "USE_BOOTLOADER=yes" to Makefile or "SET USE_BOOTLOADER=yes" to your Windows compile batch-file.
-- When USE_BOOTLOADER=yes, a special version of linker script is used: STM32F407xG_CCM_bootloader.ld. It shifts 'flash' memory address to 32kb (0x08008000), and clears a space for bootloader at the very beginning of the flash memory. It also adds section ".bl" for the bootloader code.
-- The file bootloader_storage.c used to include the bootloader code into the firmware (using '.bl' section).
-- In result, there are two binary executables combined in one firmware: the bootloader starts first, and the main firmware start afterwards.
-- All those can be overridden by board configs and makefiles - that's exactly how it's been compiled for Prometheus board.
-
-The bootloader executable works as follows:
-- Init ChibiOS and UART/Serial driver using tunerstudio_io code;
-- Create a thread to listen to UART (thBootloaderSerial), using dfuStartLoop();
-- The PC 'stm32-flasher' software sends its request byte only once, so we don't wait for it - the bootloader sends an answer as soon as it starts (both the request & answer bytes are known consts);
-- If the next command doesn't come immediately (<100 ms), we abort the bootloader dfu loop and run the application code - calling dfuJumpToApp() in main().
-- Otherwise, if at least one command is received, we stay in the bootloader mode and process commands.
+Here we combine ChibiOS with OpenBLT