STM32_MMDVM_HS HAT Guidenew pi4b need remove R1 Resistor.STM32_MMDVM_HS HAT Rev1.7 Guide1.Hardware add (SDA,SCL)R20,R21 Connect stm32 i2c 2 bus to OLED,and raspi. oled message pwr on without RPI using mmdvm_hs custom fw,and i2c 2 bus.

2.Support i2c communition with raspi

Setting For Pi-star software and raspberry hardware (rpi 0-3) new pi4b need remove R1 Resistor.

Controller Mode: Simplex Node

Radio Frequency: Freq:144-148,219-225,(Main Band)420-475,842-950

Example: 438.000000

Radio/Modem Type: STM32-DVM(GPIO)

14.7456 TCXO with RXOFFSET=0 TXOFFSET=0Quick start:1.download image https://www.pistar.uk/downloads/ write it to card

2.insert card to rpi

3.wait to boot 5 minutes connect wifi Pi-star-setup pass raspberry

4.open http://pi-star/admin/5.set freq ,dmr id ,dmr mode,add home"s wifi ssid...Default Username: pi-starDefault Password: raspberryto support i2c communication change MMDVM_HS code(by Andy Uribe CA6JAU)->Config.h// Host communication selection://#define STM32_USART1_HOST//#define STM32_USB_HOST#define STM32_I2C_HOSTto disable i2c 2 to raspi and oled just remove R20,R21 update new FW: (pi-star / expert / ssh access / user :pi-star pass:raspberry)sudo pistar-mmdvmhshatflash hs_hatps:update new FW no oled pwr on message.mode info pls visitwww.mmdvm.club