MMDVM Repeater board
Features:
Repeater and Simplex mode change anytime , through change the RX/TX board line order.
Support MMDVM mode DMR/YSF/P25/NXDN/DSTAR/POCSAG.
Double time slot in DMR mode, act as a mini Digital voice repeater.
Support VHF/UFH, frequency range: depends on your external radio.
High-quality Fox924B 12MHz TCXO, stable with low BER.
Support Raspberry Pi 3B, 3B+, Pi ZERO, Compatible with NanoPi NEO, Orange Pi, Compatible to BlueDV(Required to add USBtoTTL or Bluetooth model)
With USB interface ,can connect to Raspberry Pi and PC, inner PL2303 model.
Upgrade through ST-Link, USB, GPIO, continue upgrade support.
Specs and Docs:
Power require: 5V2A
MCU: STM32F446x
TCXO: 12.0MHz ,FOX924
HAT: 1.6mm thick,unleaded process
Interface: MicroUSB, GPIO, DB9 female, 6 PinOut
V3F4 Definition
1. Radio Data
Transmitter radio
TXA
PTT
GND
Receiver radio
RXA
RSSI
GND
Extend
HB heartbeat
Cancel
COS
2. Nextion
5V <-> HAT 5V
RXD <-> HAT TX
TXD <-> HAT RX
GND <-> HAT G
3. OLED
V3F4 Cancel OLED interface, please follow Raspberry GPIO definition, and jump line yourself.
http://mmdvm.bi7jta.org/search/label/Definition_GPIO_PCB_Case
4. Potentiometer ( High-precision )
RX : Adjust RX level
RV2: Secondary adjustment, suggest keep default
TX : Adjust TX level
RSSI: extend
5. External LED
J7 : Connect external led
J8 : Open,GND for external LED
Build up with higher performance components
STM32F446,
FOX924B 12MHz TCXO,
DB9 interface,
4PIN header for Nextion .
With DB9 cable (option 0.5/0.75/1.0/1.5 Meter)
