LFKeyboards Mini1800: refactor into revisions (#16260)

* fork Mini1800 into reva and revc versions

* update info.json

- apply friendly formatting
- update maintainer value

* update keymap rules.mk formatting

- align inline comments
- convert tabs to spaces

* align keymap rules.mk files to QMK template

* move common keymap rules.mk settings to revision level

* info.json: correct key sequence

* align revision rules.mk files to QMK template

* clean up revision rules.mk files

* add readme files for each revision

* correct USB Product string

* remove post_rules.mk files

The internal settings were commented out, so the files actually don't do anything.

* edit Bootloader instructions on main readme

* move non-assignment rules to post_rules.mk

* add inline comments for NKRO_ENABLE per fauxpark

3 files changed, 60 insertions, 0 deletions

diff --git a/keyboards/lfkeyboards/mini1800/revc/post_rules.mk b/keyboards/lfkeyboards/mini1800/revc/post_rules.mk
new file mode 100644
index 0000000000..ad997587b2
--- /dev/null
+++ b/keyboards/lfkeyboards/mini1800/revc/post_rules.mk
@@ -0,0 +1,7 @@
+ifeq ($(strip $(ISSI_ENABLE)), yes)
+    TMK_COMMON_DEFS += -DISSI_ENABLE
+endif
+
+ifeq ($(strip $(WATCHDOG_ENABLE)), yes)
+    TMK_COMMON_DEFS += -DWATCHDOG_ENABLE
+endif
diff --git a/keyboards/lfkeyboards/mini1800/revc/readme.md b/keyboards/lfkeyboards/mini1800/revc/readme.md
new file mode 100644
index 0000000000..5d442cb6d9
--- /dev/null
+++ b/keyboards/lfkeyboards/mini1800/revc/readme.md
@@ -0,0 +1,24 @@
+# Mini1800 RevC
+
+The first public release of the Mini1800.
+
+* Keyboard Maintainer: [LFKeyboards](https://github.com/lfkeyboards)
+* Hardware Supported: Mini1800 RevC (Black PCB with AT90USB646)
+* Hardware Availability: [LFKeyboards.com](https://www.lfkeyboards.com/)
+
+Make example for this keyboard (after setting up your build environment):
+
+    make lfkeyboards/mini1800/revc:default
+
+Flashing example for this keyboard:
+
+    make lfkeyboards/mini1800/revc:default:flash
+
+## Bootloader
+
+To reset the board into bootloader mode, do one of the following:
+
+* **Physical reset button**: Briefly press the button on the bottom of the PCB (between Q and W keys)
+* **Keycode in keymap**: Press the key mapped to `RESET` if it is available (`Fn`+`Right Shift`, then tap `Enter` by default)
+
+See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information. Brand new to QMK? Start with our [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
diff --git a/keyboards/lfkeyboards/mini1800/revc/rules.mk b/keyboards/lfkeyboards/mini1800/revc/rules.mk
new file mode 100644
index 0000000000..0ea69b6d6f
--- /dev/null
+++ b/keyboards/lfkeyboards/mini1800/revc/rules.mk
@@ -0,0 +1,29 @@
+# MCU name
+MCU = at90usb646
+
+# Bootloader selection
+BOOTLOADER = atmel-dfu
+
+# Build Options
+#   change yes to no to disable
+#
+BOOTMAGIC_ENABLE = no       # Enable Bootmagic Lite
+MOUSEKEY_ENABLE = no        # Mouse keys
+EXTRAKEY_ENABLE = yes       # Audio control and System control
+CONSOLE_ENABLE = no         # Console for debug
+COMMAND_ENABLE = no         # Commands for debug and configuration
+NKRO_ENABLE = yes           # Enable N-Key Rollover
+BACKLIGHT_ENABLE = yes      # Enable keyboard backlight functionality
+RGBLIGHT_ENABLE = yes       # Enable keyboard RGB underglow
+AUDIO_ENABLE = yes          # Audio output
+
+# RGB code is implemented in lfkeyboards, not WS2812
+RGBLIGHT_CUSTOM_DRIVER = yes
+BACKLIGHT_DRIVER = custom
+SLEEP_LED_ENABLE = yes
+
+ISSI_ENABLE = yes           # If the I2C pullup resistors aren't install this must be disabled
+WATCHDOG_ENABLE = yes       # Resets keyboard if matrix_scan isn't run every 250ms
+
+# Extra source files for IS3731 lighting
+SRC = TWIlib.c issi.c lighting.c