Adding information for MMDVM_HS_Hat

BUILD.md

@@ -7,6 +7,7 @@ This is a detailed guide for building the firmware of MMDVM_HS from the source c
 - ZUMspot RPi
 - ZUMspot Libre Kit
 - ZUMspot USB
+- MMDVM_HS_Hat
 - Makefile options
 - Config.h options
 - Pinout definitions
@@ -427,6 +428,13 @@ Execute MMDVMHost:
 
     ./MMDVMHost MMDVM.ini
     
+# MMDVM_HS_Hat
+
+Please check here for detailed instructions:
+
+    https://github.com/mathisschmieder/MMDVM_HS_Hat/blob/master/README.md
+
+
 # Makefile options
 
 - make clean: delete all objects files *.o, for starting a new firmware building.
@@ -437,6 +445,8 @@ Execute MMDVMHost:
 
 - make zumspot-pi: upload the firmware to a ZUMspot RPi version (using internal RPi serial port) 
 
+- make mmdvm_hs_hat: upload the firmware to MMDVM_HS_Hat board (using internal RPi serial port) 
+
 - make dfu [devser=/dev/ttyXXX]: upload firmware using USB bootloader. "devser" is optional,
 and it corresponds to the USB serial port device name. This option permits to perform a reset
 to enter to booloader mode (DFU). If you don't use "devser", you have to press the reset button
@@ -486,6 +496,8 @@ to enable this option if you have one of these products.
 - #define ADF7021_CARRIER_BOARD: enable this option if you have a ZUMspot Libre Kit (Board with
 modified RF7021SE and Blue Pill STM32F103).
 
+- #define MMDVM_HS_HAT_REV12: enable this option if you have a MMDVM_HS_Hat board for RPi. 
+
 - #define ENABLE_ADF7021: add support for ADF7021 (all boards, enabled by default).
 
 - #define DUPLEX: enable duplex mode with dual ADF7021. It is still under development.