Update readme

Author: Telekatz

README.md

@@ -1,17 +1,7 @@
-# MSC bootloader for STM32F103
+# MSC bootloader for STM32F072 and STM32F103
 
 This project was initially forked off https://github.com/mmoskal/uf2-stm32f103 though the UF2 functionality has been removed
 and replaced with the ability to load .bin firmware files.
-The size of the bootloader has been reduced to 8KiB.
-
-## Flashing bootloader from binaries
-
-You will need a STLink/v2 (or other debugger) to flash it.
-
-* https://github.com/mmoskal/uf2-stm32f103/releases
-* download the latest ZIP file (`uf2-stm32f103-vX.Y.Z.zip`)
-* run: `openocd -f interface/stlink-v2.cfg -f target/stm32f1x.cfg -c "program uf2boot-BLUEPILL.bin verify reset exit 0x8000000"`
-* see if a USB drive appears; if not reset the board twice; the LED should be fading in and out about once per second
 
 ## Build instructions
 The default target is a generic STM32F103 dev board with an LED on PC13, commonly referred to as a "bluepill" board.
@@ -20,43 +10,36 @@ To build other targets, you can override the
 `TARGET` variable when invoking `make`.
 
     make clean
-    make TARGET=STLINK
+    make TARGET=MAPLEMINI
 
 ### Targets
 
-| Target Name | Description | Link |
-| ----------- | ----------- |----- |
-|`BLUEPILL`   | Cheap dev board | http://wiki.stm32duino.com/index.php?title=Blue_Pill |
-|`MAPLEMINI`  | LeafLabs Maple Mini board and clone derivatives | http://wiki.stm32duino.com/index.php?title=Maple_Mini |
-
+| Target Name | Description | Bootloader offset | Link |
+| ----------- | ----------- |------------------ | ---- |
+|`STM32F103`  | Generic STM32F103 target without LED | 8KiB |  |
+|`STM32F072`  | Generic STM32F072 target without LED | 16KiB |  |
+|`BLUEPILL`   | Cheap dev board | 8KiB | http://wiki.stm32duino.com/index.php?title=Blue_Pill |
+|`MAPLEMINI`  | LeafLabs Maple Mini board and clone derivatives | 8KiB | http://wiki.stm32duino.com/index.php?title=Maple_Mini |
 
-## Flash instructions
-
-The `make flash` target will use openocd to upload the bootloader to an attached board.
-By default, the Makefile assumes you're using a STLink v2 based probe, but you can override this by overriding `OOCD_INTERFACE` variable. For example:
-
-    make OOCD_INTERFACE=interface/cmsis-dap.cfg flash
 
 ## Overriding defaults
 Local makefile settings can be set by creating a `local.mk`, which is automatically included.
 
-Here is an example `local.mk` that changes the default target to the STLink/v2 and uses an unmodified STLink/v2 to flash it.
+Here is an example `local.mk` that changes the default target to the MAPLEMINI.
 
     TARGET ?= STLINK
-    OOCD_INTERFACE ?= interface/stlink-v2.cfg
 
 ## Using the bootloader
 ### Building for the bootloader
-The bootloader occupies the lower 8KiB of flash, so your application must offset its flash contents by 8KiB. This can be done by modifying your linker script or flags as appropriate.
+The bootloader occupies the lower 8KiB or 16KiB of flash, so your application must offset its flash contents by 8KiB or 16KiB. This can be done by modifying your linker script or flags as appropriate.
 
 ### Switching to the bootloader
 The bootloader can be built to look for arbitrary patterns, but the default for the STM32F103 target looks for a magic value stored in the RTC backup registers. Writing the magic value and then resetting will run the bootloader instead of the main application.
+When compiling with the DOUBLE_TAP option, the bootloader can be activated by double-tapping the reset button.
 
 ## Licensing
 All contents of the dapboot project are licensed under terms that are compatible with the terms of the GNU Lesser General Public License version 3.
 
 Non-libopencm3 related portions of the dapboot project are licensed under the less restrictive ISC license, except where otherwise specified in the headers of specific files.
 
-The UF2 parts are licensed under MIT.
-
 See the LICENSE file for full details.