Add Bluepill (stm32f103) handwired keyboard (#4126)

* Main folder

Main folder with some changes like the base layout and matrix for uploading in a future to the qmk repositorie

* First Commit

Firsts non previously commited changes:
-Changed to keyboards/handwired
-Basic credit to Xydane
-70% Layout

* Modified file structure for several keyboards

As I don't want to create several folders and overcrowd the main folders I made a few modifications to being able of configure several keyboards as revisions of the main keyboard.
Added a second variant.
Compiling tests went right but I haven't tried it on the controller.

* Starting leds

* Started dual color leds PWM functions and configs

I started to create the PWM functions and configs based on internet examples, it doesn't compile yet

* Backtraced a bit to establish and try debug before continuing the pwm

Just this, algo some doc as a new pinout image, space cadet modification to try if it works and little more

* Deleted unuseful stuff

After trying the reestructure to being compatible with several keyboards and that it worked I deleted the other keyboard.
Added space cadet shift to ISO.
Finally I couldn't debug everything and I'm getting quite frustrated to continue much more than just adding pwm leds

* Changed again Iso fix for Space Cadet

* Renamed keyboard, future pull

I just renamed the keyboard and made some simplifying changes in order to make a pull request sometime soon.

I'm too frustrated, tired and knowledge limited to achive using the PWM for leds, I didn't even get to use the debug mode...

I intend to end basic led color change using layers (if I can), document everything properly and make a pull request so other users can continue/use this project.

* Writed Readme.md file

I also corrected a previous compilation problem and ordered a bit the keymaps

* Corrected readme

* Try to add layer activated light

* Revert "Try to add layer activated light"

This reverts commit 205af820d845dab08988f329b9f062f558060220.

* Progress to fork

Coming back to work, upcoming pull

* Linked image

Corrected readme

* Some cleanning

Added images to readme, som cleaning, burning after commit.

* Almost finished (working)

Finally

* Finished bluepill firmware

Just finished and tried layer dependant led colors. Going for merge

* Deleted innecesary stuff and trailing spaces

Just as commit title said.

* Coding conventions

Just modified some files to respect coding conventions

* Deleted XXXXXX define

Checking some other PR seen this improvement

* Changes suggested on PR

Firs doing the easy changes

* More changes for the PR

-I also deleted one unused function for led toggling on matrix.c (Now it uses layer dependent baklight, algo on of on start)
-Deleted commented function on keymaps.

Right now only needs testing and all pragma replaces.

* Almost every pragma change on PR

That's almost finished, only waiting for reply due to compiling errors

* Revert "Almost every pragma change on PR"

This reverts commit 07f23aa862b370cdf0ae37d6f2130c9e9856f491.

* Revert last commit

I moddified by mistake a file from another keyboard

* Solved last pragma

Compiles fine.
Now I only need to test it, I say you if it works to include it in the main repository.

keyboards/handwired/bluepill/bluepill70/rules.mk

@@ -0,0 +1,47 @@
+# project specific files
+SRC =	matrix.c \
+	    led.c
+
+# GENERIC STM32F103C8T6 board - stm32duino bootloader
+#OPT_DEFS = -DCORTEX_VTOR_INIT=0x2000
+#MCU_LDSCRIPT = STM32F103x8_stm32duino_bootloader
+#BOARD = GENERIC_STM32_F103
+
+# GENERIC STM32F103C8T6 board - no bootloader (programmer over serial or SWD) //  Modified by Xydane
+OPT_DEFS =
+MCU_LDSCRIPT = STM32F103x8
+BOARD = GENERIC_STM32_F103
+
+# MAPLE MINI
+# OPT_DEFS = -DCORTEX_VTOR_INIT=0x5000
+# MCU_LDSCRIPT = STM32F103xB_maplemini_bootloader
+# BOARD = MAPLEMINI_STM32_F103
+
+## chip/board settings
+# the next two should match the directories in
+#  <chibios>/os/hal/ports/$(MCU_FAMILY)/$(MCU_SERIES)
+MCU_FAMILY = STM32
+MCU_SERIES = STM32F1xx
+# linker script to use
+# it should exist either in <chibios>/os/common/ports/ARMCMx/compilers/GCC/ld/
+#  or <this_dir>/ld/
+# startup code to use
+# is should exist in <chibios>/os/common/ports/ARMCMx/compilers/GCC/mk/
+MCU_STARTUP = stm32f1xx
+# it should exist either in <chibios>/os/hal/boards/
+#  or <this_dir>/boards
+# Cortex version
+# Teensy LC is cortex-m0; Teensy 3.x are cortex-m4
+MCU  = cortex-m3
+# ARM version, CORTEX-M0/M1 are 6, CORTEX-M3/M4/M7 are 7
+ARMV = 7
+# If you want to be able to jump to bootloader from firmware on STM32 MCUs,
+# set the correct BOOTLOADER_ADDRESS. Either set it here, or define it in
+# ./bootloader_defs.h or in ./boards/<FOO>/bootloader_defs.h (if you have
+# a custom board definition that you plan to reuse).
+# If you're not setting it here, leave it commented out.
+# It is chip dependent, the correct number can be looked up here (page 175):
+# http://www.st.com/web/en/resource/technical/document/application_note/CD00167594.pdf
+# This also requires a patch to chibios:
+#   <tmk_dir>/tmk_core/tool/chibios/ch-bootloader-jump.patch
+#STM32_BOOTLOADER_ADDRESS = 0x1FFFC800