Dual-Band UHF/VHF Antenna MMDVM Hotspot for Raspberry Pi - Supports P25 DMR YSF

STM32 MMDVM HS HAT Guide

If using a new Raspberry Pi 4B, please remove the R1 resistor.

STM32 MMDVM HS HAT Rev1.7 Guide

1. Hardware enhancements (SDA, SCL): R20, R21 connect the STM32 I2C 2 bus to the OLED and Raspberry Pi. This allows OLED messages to display when powered on, even without the Raspberry Pi, using custom MMDVM_HS firmware and the I2C 2 bus.
2. Supports I2C communication with Raspberry Pi.

Settings for Pi-Star software and Raspberry Pi hardware (Raspberry Pi 0-3): If using a new Pi 4B, removal of the R1 resistor is necessary.

Configuration

• Controller Mode: Simplex Node
• Radio Frequency: 144-148, 219-225 (Main Band), 420-475, 842-950 MHz
• Example Frequency: 438.000000 MHz
• Radio/Modem Type: STM32-DVM (GPIO)
• 14.7456 MHz TCXO with RXOFFSET=0, TXOFFSET=0

Quick Start Guide

1. Download the image from here and write it to the SD card.
2. Insert the card into the Raspberry Pi.
3. Wait 5 minutes for booting and connect to Wi-Fi: Pi-star-setup (password: raspberry).
4. Open http://pi-star/admin/ in a web browser.
5. Set frequency, DMR ID, DMR mode, and add your home’s Wi-Fi SSID.

Default Username: pi-star
Default Password: raspberry

To Support I2C Communication

Edit the MMDVM_HS code (by Andy Uribe CA6JAU) in Config.h:

// Host communication selection:
//#define STM32_USART1_HOST
//#define STM32_USB_HOST
#define STM32_I2C_HOST
    

To disable I2C 2 to Raspberry Pi and OLED, simply remove R20, R21.

Update Firmware

Using Pi-Star / Expert / SSH Access (user: pi-star, pass: raspberry), run the following command:

sudo pistar-mmdvmhshatflash hs_hat

Note: Updating firmware removes the OLED power-on message.

For more information, please visit www.mmdvm.club.