UHF VHF UV for mmdvm Hotspot Module for DMR P25 YSF DSTAR Pi Zero 3B 3B with OL

Description:
Our simplex and duplex systems all use an offset of 0, which is our duplex system. Regardless of simplex or duplex, the offset is 0.
We are using high-precision temperature compensated crystals, so it is 0
We use high cost TCXO crystal with extremely low bit error rate, offset of 0,
and frequency error of 0

new pi4b need remove R1 Resistor.
STM32_for MMDVM_HS HAT Rev1.7 Guide

1.Hardware add (SDA,SCL)R20,R21 Connect stm32 i2c 2 bus to OLED,and raspi. oled message pwr on without RPI using for mmdvm_hs custom fw,and i2c 2 bus.
2.Support i2c communication with raspi
Setting For Pi-star software and for 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=0

Quick 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 for raspberry
4.open http://pi-star/admin/
5.set freq,dmr id,dmr mode,add home's wifi ssid...
Default Username: pi-star
Default Password: for raspberry

to support i2c communication change for MMDVM_HS code(by Andy Uribe CA6JAU)->Config.h

// Host communication selection:
//#define STM32_USART1_HOST
//#define STM32_USB_HOST
#define STM32_I2C_HOST
to 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-for mmdvmhshatflash hs_hat
ps:update new FW no oled pwr on message.
mode info pls visit

The for MMDVM hotspot support module can work with UHF or VHF(VHF is not the main band)

Specification:
· High performance 32-bit AR M processor
· Fully assembled and tested
· Supports DMR, P-25, D-Star and System Fusion
· Onboard LEDs to show status (Tx, Rx, PTT, Mode)
· Up to 10mW RF power
· SMA antenna connector, UHF&VHF antenna included
· Mounts cleanly on all current Raspberry Pi's including the Pi Zero
· The firmware is pre-loaded and is easily upgraded via software.
·UHF 433 900 MHZ, VHF 144 220 MHZ Opera FREQ
· Supported and tested with PI-STAR
Please note: The product does not come with a memory card or motherboard. You need to start it to connect to the hotspot, insert the memory card, and then connect to the hotspot to light up the screen.

Packing list:
1*Single hotspot expansion board
1*OLED screen
1*shell
1*Antenna

Please do not upgrade the firmware by yourself, if you have not the knowledge for it.
The product needs to be soldered with the pi motherboard (not included), please make sure you know it before buying.

Note:
1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness.
2. Please allow slight manual measurement deviation for the data.