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D2RG_MMDVM_HS_ambe_uart_service

D2RG MMDVM HS AMBE Raspberry Pi (RPi) HAT uses NXP SC16IS752 as a SPI-UART converter to extend the number of UART ports, an MMDVM HS is connected to SC16IS752 UART A, UART B is unused but can be used as a general purposed UART, and it is on the left (upper left corner) of the MMDVM HS AMBE HAT board.

Device Tree [RPi, assume you have the latest Raspbian running]:

<b>sc16is752-spi0-ce0.dts</b> is for SC16IS752 via RPi SPI 0 with CE/CS=0 (GPIO08) - MMDVM HS AMBE hardware configuration.

The .dts file needs to be compiled as .dtb and put to /boot/overlays (SD Card)

dtc -@ -I dts -O dtb -o sc16is752-spi0-ce0.dtb sc16is752-spi0-ce0.dts

And adding:

dtoverlay=sc16is752-spi0-ce0

to config.txt under /boot (SD Card)

Then allocate serial UART interfaces to /dev/ttySC0 and /dev/ttySC1 - A and B of SC16IS752.

Patch the Pi-Star under terminal:

rpi-rw

sudo su

curl -OL https://raw.githubusercontent.com/bg3mdo/D2RG_MMDVM_HS_ambe_uart_service/master/sc16is752-spi0-ce0.dts

dtc -@ -I dts -O dtb -o sc16is752-spi0-ce0.dtb sc16is752-spi0-ce0.dts

sudo mv sc16is752-spi0-ce0.dtb /boot/overlays

sudo echo "dtoverlay=sc16is752-spi0-ce0" >> /boot/config.txt

Setting up everything as normal, and go to pi-star expert mode, in the MMDVMhost, you change modem port to /dev/ttySC0 and apply settings.

Flash a firmware for D2RG MMDVM HS AMBE

Credit to Andy(CA6JAU)

curl -OL https://raw.github.com/juribeparada/MMDVM_HS/master/scripts/install_fw_d2rg_mmdvmhs.sh

chmod +x install_fw_d2rg_mmdvmhs.sh

sh install_fw_d2rg_mmdvmhs.sh

D2RG MMDVM HS AMBE hardware prototype

This project is supported by Bruce(VE2GZI).