Building instructions:
===================== 
1) Raspberry Pi with ZUMSpot Pi:

* Download latest Raspbian image and install to a micro SD
- See: https://www.raspberrypi.org/documentation/installation/installing-images/
- Configure your SD before booting. Useful article:
  https://styxit.com/2017/03/14/headless-raspberry-setup.html
- Boot your Raspberry Pi
- Run raspi-config and configure according your preferences:
sudo raspi-config
(at least expand filesystem and change default password. It's a good idea to enable "Wait
for Network at Boot" and disable Desktop GUI if you don't plan to use it)

* Enable serial port /dev/ttyAMA0 (Raspberry Pi 3 or Pi Zero W only):
- Edit /boot/cmdline.txt
sudo nano /boot/cmdline.txt
(remove the text: console=serial0,115200)

- Disable services:
sudo systemctl disable serial-getty@ttyAMA0.service
sudo systemctl disable bluetooth.service

- Edit /boot/config.txt
sudo nano /boot/config.txt
(add the following lines):
enable_uart=1
dtoverlay=pi3-disable-bt

- Reboot the RPi:
sudo reboot

* Enable serial port /dev/ttyAMA0 (Raspberry Pi 2 only):
- Edit /boot/cmdline.txt
sudo nano /boot/cmdline.txt
(remove the text: console=serial0,115200)

- Disable services:
sudo systemctl disable serial-getty@ttyAMA0.service

- Reboot the RPi:
sudo reboot

* Build de firmware and upload to ZUMSpot:
cd ~
- Install the necessary software tools:
sudo apt-get update
sudo apt-get install gcc-arm-none-eabi gdb-arm-none-eabi libstdc++-arm-none-eabi-newlib libnewlib-arm-none-eabi
git clone https://git.code.sf.net/p/stm32flash/code stm32flash
cd stm32flash
make
sudo make install
cd ~

- Download the sources:
git clone https://github.com/juribeparada/MMDVM_HS
cd MMDVM_HS/
git clone https://github.com/juribeparada/STM32F10X_Lib

- Edit Config.h
nano Config.h
(and enable):
#define PI_HAT_7021_REV_03
#define ENABLE_ADF7021
#define ADF7021_N_VER (only if your board uses ADF7021N)
#define BIDIR_DATA_PIN
#define ADF7021_14_7456
#define STM32_USART1_HOST
#define ENABLE_SCAN_MODE

- Build the firmware:
make

- Upload the firmware to ZUMSpot Pi board:
sudo make zumspot-pi

* Install MMDVMHost:
cd ~
git clone https://github.com/g4klx/MMDVMHost/
cd MMDVMHost/
make

- Edit MMDVM.ini according your preferences
nano MMDVM.ini
(use Port=/dev/ttyAMA0 in [Modem])

- Execute MMDVMHost:
./MMDVMHost MMDVM.ini

2) ZUMSpot USB:

* Windows:
- Download and install the version 1.6.9 of the Arduino IDE:
https://www.arduino.cc/en/Main/OldSoftwareReleases#previous

- Download STM32duino (Arduino for STM32) from this URL:
https://github.com/rogerclarkmelbourne/Arduino_STM32/tree/ZUMspot

- Unzip to create the Arduino_STM32 folder

- Copy Arduino_STM32 folder in:
My Documents/Arduino/hardware

- Install the USB bootloader to STM32F103. Follow the instructions:
https://github.com/rogerclarkmelbourne/Arduino_STM32/wiki/stm32duino-bootloader

- Download the source (zip file) of MMDVM_HS from https://github.com/juribeparada/MMDVM_HS
(Do not download or install the STM32F103 libraries, STM32F10X_Lib, they are not necessary
under STM32duino).

- Unzip MMDVM_HS-master.zip in a local folder.

- Start the Arduino IDE. Open the MMDVM_HS.ino file in the MMDVM_HS folder.

- Under the menu "Tools" select "Board" and then select:
Board: Generic STM32F103C Series
Variant: STM32F103C8 (20k RAM, 64k Flash)
CPU Speed: 72 MHz (Normal)
Upload method: STM32duino bootloader (you have transfered the USB bootloader before)
Serial port: COMx (Maple Mini)

- Edit Config.h according your board:
#define PI_HAT_7021_REV_03 (only if your board is ZUMSpot USB)
#define ADF7021_CARRIER_BOARD (only if your board is ZUMSpot Libre Kit)
#define ENABLE_ADF7021
#define ADF7021_N_VER (only if your board uses ADF7021N)
#define BIDIR_DATA_PIN
#define ADF7021_14_7456
#define STM32_USB_HOST
#define ENABLE_SCAN_MODE

- Click the Upload button in the IDE and wait for the transfer.

- Once the transfer is completed, press the RESET button of the board. In the case of
ZUMSpot Libre Kit, you will see the LED (PC13) of the blue pill blinking.

- Once you connect with MMDVMHost, the LED will blink fast in the ZUMSpot Libre Kit.

* Linux Raspbian:
cd ~
- Install the necessary software tools:
sudo apt-get update
sudo apt-get install gcc-arm-none-eabi gdb-arm-none-eabi libstdc++-arm-none-eabi-newlib libnewlib-arm-none-eabi

- Download the sources:
git clone https://github.com/juribeparada/MMDVM_HS
cd MMDVM_HS/
git clone https://github.com/juribeparada/STM32F10X_Lib

- Edit Config.h
nano Config.h
(and enable):
#define PI_HAT_7021_REV_03 (only if your board is ZUMSpot USB)
#define ADF7021_CARRIER_BOARD (only if your board is ZUMSpot Libre Kit)
#define ENABLE_ADF7021
#define ADF7021_N_VER (only if your board uses ADF7021N)
#define BIDIR_DATA_PIN
#define ADF7021_14_7456
#define STM32_USB_HOST
#define ENABLE_SCAN_MODE

- Build the firmware with bootloader support:
make bl

- Upload bootloader and firmware to ZUMSpot USB board, using serial port first (you
are using an USB-serial converter with device name /dev/ttyUSB0):

Hold BOOT0 (or move BOOT0 jumper to 1), next press and release RESET

sudo make serial-bl devser=/dev/ttyUSB0

Release BOOT0 (or move BOOT0 jumper to 0)

- For following firmware updates, you could use the USB port directly:
sudo make dfu devser=/dev/ttyACM0

* Install MMDVMHost:
cd ~
git clone https://github.com/g4klx/MMDVMHost/
cd MMDVMHost/
make

- Edit MMDVM.ini according your preferences
nano MMDVM.ini
(use Port=/dev/ttyACM0 in [Modem])

- Execute MMDVMHost:
./MMDVMHost MMDVM.ini

3) Makefile options:

make clean: delete all objects files *.o, for starting a new firmware building.

make: it builds a standard firmware (without USB bootloader support).

make bl: it builds a firmware with USB bootloader support.

make zumspot-pi: upload the firmware to a ZUMSpot Pi version (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
of the ZUMSpot just before using this command.

make serial devser=/dev/ttyXXX: upload standard firmware using serial port bootloader method.

make serial-bl devser=/dev/ttyXXX: upload firmware with USB bootloader support using serial
port bootloader method.

make stlink: upload standard firmware using ST-Link interface.

make stlink-bl: upload firmware with USB bootloader support using ST-Link interface.

make ocd: upload standard firmware using ST-Link interface. This method uses a local
openocd installation.

make ocd-bl: upload firmware with USB bootloader support using ST-Link interface. This
method uses a local openocd installation.

* Common Makefile commands:
- Serial programming (first programming, transfer the USB bootloader):
make clean
make bl
sudo make serial-bl devser=/dev/ttyUSB0

- USB programming (you have already transfered the USB bootloader):
make clean
make bl
sudo make dfu (reset ZUMSpot before) or
sudo make dfu devser=/dev/ttyACM0 (/dev/ttyACM0 is the device name of ZUMSpot USB under
Raspbian)

- ZUMSpot Pi (no USB support needed):
make clean
make
sudo make zumspot-pi

4) Config.h options:

#define PI_HAT_7021_REV_02: enable pinouts for first revision of ZUMSpot Pi. In general is
not used.

#define PI_HAT_7021_REV_03: enable pinouts support for ZUMSpot Pi or ZUMSpot USB. You have
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 ENABLE_ADF7021: add support for ADF7021 (all boards, enabled by default).

#define ADF7021_N_VER: enable support for narrow band version of ADF7021 (ADF7021N). Disabled
by default, in general all boards will have just ADF7021.

#define DUPLEX: enable duplex mode with dual ADF7021. It is still under development.

#define BIDIR_DATA_PIN: enable Standard TX/RX Data Interface of ADF7021 (enabled by default, 
needed for scanning mode detection feature).

#define ADF7021_14_7456: select this option if your board uses a 14.7456 MHz (enabled by default).

#define ADF7021_12_2880: select this option if your board uses a 12.2880 MHz.

#define ADF7021_ENABLE_4FSK_AFC: enable AFC support for DMR, YSF and P25. This is experimental,
depending on your frequency offset this option will improve or not your BER reception.

#define ADF7021_AFC_POS: enable this option if you can not receive any signal after enable the
ADF7021_ENABLE_4FSK_AFC option.

#define STM32_USART1_HOST: enable direct serial host communication with ZUMSpot (using USART1
PA9 and PA10 pins). Disable STM32_USB_HOST if you enable this option. Enable this if you have
a ZUMSpot Pi. You don't need to enable this option if you will transfer the bootloader.

#define STM32_USB_HOST: enable USB host communication with ZUMSpot (using STM32F103 USB
interface). Disable STM32_USART1_HOST if you enable this option. Enable this if you have
a ZUMSpot USB or ZUMSpot Libre Kit.

#define ENABLE_SCAN_MODE: enable automatic mode detection in ZUMSpot. This is based on
scanning over all enabled modes, and you could have some detection delay. Enabled by default.

#define SEND_RSSI_DATA: enable RSSI reports to MMDVMHost. It is already converted to dBm.

#define SERIAL_REPEATER: enable a second serial port (USART2, pins PA2 and PA3) for Nextion
LCD display.

Pinout definitions for ZUMSpot Libre Kit (Carrier board, RF7021SE + STM32F103 board):
=====================================================================================
- Main RF7021SE board:
CE             PC14
SLE            PB8
SREAD          PB7
SDATA          PB6
SCLK           PB5
DATA           PB4 (TxRxData)*
DCLK           PB3 (TxRxCLK)*
CLKOUT         PA15 (jumper wire in RF7021SE)
PAC            PB14 (PTT LED)
VCC            3.3 V
GND            Ground

- Second RF7021SE board (duplex mode, experimental):
SLE            PA6
DATA           PA4 (TxRxData)*
DCLK           PA5 (TxRxCLK)*
PAC            NC
CLKOUT         NC
VCC            3.3 V
GND            Ground

SDATA, SREAD, SCLK and CE are shared with the main ADF7021.

- Serial ports:
TXD            PA9 (serial port host communication)
RXD            PA10 (serial port host communication)
DISP_TXD       PA2 (Nextion LCD serial repeater)
DISP_RXD       PA3 (Nextion LCD serial repeater)

- Status LEDs:
COS_LED        PB15
PTT_LED        PB14
P25_LED        PB0
YSF_LED        PB1
DMR_LED        PB13
DSTAR_LED      PB12

- Misc pins:
PIN_LED        PC13 (status led)
PIN_DEB        PB9 (debugging pin)

* You could install a serie resistor (10 - 100 ohms) in each TxRxData and TxRxCLK lines, for
reducing EMI.

Pinout definitions for Arduino Due/Zero + RF7021SE:
===================================================
Use STM32duino + Arduino IDE for building the code 

- Main RF7021SE board:
CE            12
SLE            6
SREAD          5
SDATA          4   // 2 in Arduino Zero Pro
SCLK           3 
DATA           7 (TxRxData)*
DCLK           8 (TxRxCLK)*
CLKOUT         2   // 4 in Arduino Zero Pro  (jumper wire in RF7021SE)
PAC            9 (PTT LED)
VCC            3.3 V
GND            Ground

- Serial ports:
USB Arduino Programming Port (host communication)

- Status LEDs:
COS_LED       10
PTT_LED        9
P25_LED       17
YSF_LED       16
DMR_LED       15
DSTAR_LED     14

- Misc pins:
PIN_LED       13
PIN_DEB       11

* You could install a serie resistor (10 - 100 ohms) in each TxRxData and TxRxCLK lines, for
reducing EMI.