Remove BTTSKRMINIE3V2_USBMOD, use BTTSKRMINIE3V2 instead

For the past two years I've had only occasional issues with a
BTTSKRMINIE3V2_USBMOD build my the SKR MINI, but after upgrading to a faster Pi
(64-bit OS) for Klipper, some major problems with this mod became evident.
Hard-wiring the USB D+ pullup to 3V3 causes the host to enumerate it as soon as
a soft reset is issued, whereby the firmware (and this bootloader) have not had
time to properly initialize and get USB ready. This stalls USB hubs, times out
the Ethernet controller on Raspberry Pis, and causes all kinds of other issues,
thus, I'm discouraging its use and removing the target.

Regarding the debugging difficulties motivating BTTSKRMINIE3V2_USBMOD, they can
be solved with a proper debugging setup. I'm able to successfully debug the MCU
even with the USB pullup MOSFET and the STATUS LED attached to SWDCLK and SWDIO
respectively using a FT232H. As such, the BTTSKRMINIE3V2 target should be used
instead, and I've also re-added control of the STATUS LED to indicate
bootloader presence.

Author: twelho

README.md

@@ -22,7 +22,6 @@ To build other targets, you can override the
 |`OLIMEXSTM32H103` | Olimex STM32-H103 | https://www.olimex.com/Products/ARM/ST/STM32-H103/ |
 |`BLUEPILLPLUSSTM32` | Bluepill with USB C | https://github.com/WeActTC/BluePill-Plus/ |
 |`BTTSKRMINIE3V2` | BigTreeTech SKR MINI E3 V2.0 (3D printer motherboard) | https://github.com/bigtreetech/BIGTREETECH-SKR-mini-E3 |
-|`BTTSKRMINIE3V2_USBMOD` | BTT SKR MINI E3 V2.0 with USB pullup removed | https://github.com/bigtreetech/BIGTREETECH-SKR-mini-E3 |
 
 For the above targets there are some potential variants that can be added to the target name based on what the target supports:
 

release.Makefile

@@ -35,7 +35,6 @@ all: dapboot-bluepill.bin \
      dapboot-olimexstm32h103.bin \
      dapboot-bluepillplusstm32.bin \
      dapboot-bttskrminie3v2.bin \
-     dapboot-bttskrminie3v2-usbmod.bin \
      dapboot-bluepill-high.bin \
      dapboot-maplemini-high.bin \
      dapboot-stlink-high.bin \
@@ -46,8 +45,7 @@ all: dapboot-bluepill.bin \
      dapboot-stlink-high-128.bin \
      dapboot-olimexstm32h103-high-128.bin \
      dapboot-bluepillplusstm32-high-128.bin \
-     dapboot-bttskrminie3v2-high-256.bin \
-     dapboot-bttskrminie3v2-usbmod-high-256.bin
+     dapboot-bttskrminie3v2-high-256.bin
 
 clean:
 	$(Q)$(RM) $(BUILD_DIR)/*.bin
@@ -94,12 +92,6 @@ dapboot-bttskrminie3v2.bin: | $(BUILD_DIR)
 	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2 -C src/
 	$(Q)cp src/dapboot.bin $(BUILD_DIR)/$(@)
 
-dapboot-bttskrminie3v2-usbmod.bin: | $(BUILD_DIR)
-	@printf "  BUILD $(@)\n"
-	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_USBMOD -C src/ clean
-	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_USBMOD -C src/
-	$(Q)cp src/dapboot.bin $(BUILD_DIR)/$(@)
-
 dapboot-bluepill-high.bin: | $(BUILD_DIR)
 	@printf "  BUILD $(@)\n"
 	$(Q)$(MAKE) TARGET=BLUEPILL_HIGH -C src/ clean
@@ -165,9 +157,3 @@ dapboot-bttskrminie3v2-high-256.bin: | $(BUILD_DIR)
 	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_HIGH_256 -C src/ clean
 	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_HIGH_256 -C src/
 	$(Q)cp src/dapboot.bin $(BUILD_DIR)/$(@)
-
-dapboot-bttskrminie3v2-usbmod-high-256.bin: | $(BUILD_DIR)
-	@printf "  BUILD $(@)\n"
-	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_USBMOD_HIGH_256 -C src/ clean
-	$(Q)$(MAKE) TARGET=BTTSKRMINIE3V2_USBMOD_HIGH_256 -C src/
-	$(Q)cp src/dapboot.bin $(BUILD_DIR)/$(@)

src/stm32f103/skrminie3v2/config.h

@@ -36,10 +36,18 @@
 #define DFU_WILL_DETACH 0
 #endif
 
-/* There is a PCB-mounted status LED, but it's unreadable when the board is installed,
- * and additionally it's wired to SWDIO so toggling it manually is a bad idea */
+/* STATUS LED */
 #ifndef HAVE_LED
-#define HAVE_LED 0
+#define HAVE_LED 1
+#endif
+#ifndef LED_OPEN_DRAIN
+#define LED_OPEN_DRAIN 0
+#endif
+#ifndef LED_GPIO_PORT
+#define LED_GPIO_PORT GPIOA
+#endif
+#ifndef LED_GPIO_PIN
+#define LED_GPIO_PIN GPIO13
 #endif
 
 /* Display encoder button (BTN-ENC) on PA15, no external pullup */
@@ -82,8 +90,8 @@
 #define USES_GPIOA 1
 #endif
 
-/* For stm32duino bootloader compatibility, the following options enable
- * bootloader flashing using KIAUH: https://github.com/th33xitus/kiauh */
+/* For stm32duino bootloader compatibility, the following options enable bootloader flashing using Klipper:
+ * https://github.com/Klipper3d/klipper/blob/6d48adf9ef5d17632acf53a7e3a07964f6cfd642/src/stm32/stm32f1.c#L238 */
 #ifndef REG_BOOT
 #define REG_BOOT BKP10
 #endif

src/stm32f103/skrminie3v2_usbmod/config.h

@@ -139,19 +139,6 @@ ifeq ($(TARGET),BTTSKRMINIE3V2_HIGH_256)
 	ARCH			= STM32F1
 	DEFS			+= -DBOOTLOADER_HIGH
 endif
-ifeq ($(TARGET),BTTSKRMINIE3V2_USBMOD)
-	TARGET_COMMON_DIR	:= ./stm32f103
-	TARGET_SPEC_DIR		:= ./stm32f103/skrminie3v2_usbmod
-	LDSCRIPT		:= ./stm32f103/stm32f103x8.ld
-	ARCH			= STM32F1
-endif
-ifeq ($(TARGET),BTTSKRMINIE3V2_USBMOD_HIGH_256)
-	TARGET_COMMON_DIR	:= ./stm32f103
-	TARGET_SPEC_DIR		:= ./stm32f103/skrminie3v2_usbmod
-	LDSCRIPT		:= ./stm32f103/stm32f103xc_high.ld
-	ARCH			= STM32F1
-	DEFS			+= -DBOOTLOADER_HIGH
-endif
 ifeq ($(TARGET),STM32L1_GENERIC)
 	TARGET_COMMON_DIR	:= ./stm32l1
 	TARGET_SPEC_DIR		:= ./stm32l1/generic