Flashing-on-a-Target-Board.md

-> TODO: document the USB way and the serial port way
+So, you wrote your driver and then compiled it: now want to run it on a STM32 microcontroller. To do this, there are several ways, depending on your board's configuration.
 
-So, you wrote your driver and then compiled it: now want to run it on a board.
+## Method 1: USB
 
-You can start using a STM32 Discovery board: these are very 
-versatile boards that you can easily use for test porpouses. Otherwise, if you have one,
-you can directly flash it on one of Skyward's Tropper/Anakin boards.
+If you are using a Discover board, you can directly plug your board to your PC with a USB cable. You will need some drivers that are available one the vendor's site. Once the PC has recognized tour board, you have two options.
 
-### Requirements
-You'll need a binary file (bin, elf...) that you have built for the right board
- using SBS (see [here](./Skyward-Build-Systems-(SBS))).
+### 1.1 Drag and Drop
 
-Then obviously you'll need a board and a USB-to-MiniUSB cable that you'll have to plug
- to the corresponding port (if the board has two, it's the biggest one).
- 
- What's written here is taken from Miosix's Quick start guide: <https://miosix.org/wiki/index.php?title=Quick_start#Getting_started>.
+Some boards support drag and drop: simply select your .bin file and drop it in the device.
 
+### 1.2 ST-Link software
 
-**Software**
+If this doesn't work, you can try downloading an ST-Link utility, which is provided with a GUI. You will need to press Connect, flash your binary, verify it and then power cycle the board.
 
 *Windows*
 
@@ -34,19 +28,24 @@ wget https://raw.githubusercontent.com/mobyfab/QStlink2/master/res/49-stlinkv2.r
 sudo mv 49-stlinkv2.rules /etc/udev/rules.d
 sudo chown root:root /etc/udev/rules.d/49-stlinkv2.rules
 ```
-Or you can use `stm32flash` or `openocd` from CLI (the last one is needed to run SBS's script).
 
-### Discovery Boards
 
-**Flashing**
+## Method 2: USART
 
-Discovery boards are quite simple to use: plug your board via usb to your PC and then
-use QSTLink to flash the binary file on the board. 
+If your board has at least a USART port accessible, you can also flash binaries through it. To do this, you'll need a USB-TTL module and you need to have access to the following pins of your STM32:
 
-Or, if you prefer, you can use two scripts that you can find in the `scripts\` folder:
+* BOOT0
+* BOOT1
+* NRST
+* USART RX
+* USART TX
 
-- start_openocd.sh: starts openocd(leave it in background)
-- openocd-flash.sh <binary_file_name>: connects to openocd using gdb and
-														uses it to flash the binary file into the connected board.
+You also need `stm32flash` installed.
+
+**Procedure**
+1. Connect BOOT0 to VDD and BOOT1 to GND
+2. Reset the board by pulling NRST to GND and then leave it floating
+3. try `stm32flash /dev/ttyUSB0` or `ttyS0`
+4. if the board information is printed, flash with `stm32flash -b <BAUDRATE> -w <BINARYNAME> /dev/ttyUSB0` or whatever device the USB-TTL is attached.
+5. once finished, restore BOOT0 and BOOT1 values and reset the board.
 
-If the program is not running, power-cycle the board and you'll see it working!