LARS GPSDO Programming

• Arduino Nano ATmega328p
• Plug in board, should recognize as "USB-SERIAL CH340 (COM##)"
• Use "Arduino Nano" as Board Type
• Use "ATmega328p (Old Bootloader)" as Processor
• Use "Blank" as Programmer (nothing should be selected)
• Check then upload code
• Should reboot and start running code after upload complete
• New COM port should show up after code upload, select board type and COM port to connect and see scrolling mesages
• Enter h1 to get min DAC value
• Enter H65536 to get max DAC value
• Calculate range of DAC and divide by 65536 to calculate gain
• Enter g### to enter value for gain
• Enter s1 to save gain value
• Enter r to run closed loop
• See printed notes for more info
• Lars GPSDO Info: https://github.com/paulvee/Lars-GPSDO-V1

AndrewBCN GPSDO Programming

• STM32F411ceu6 BlackPill

• https://github.com/AndrewBCN/STM32-GPSDO

• Plug in and reboot while holding boot0 (hold both buttons down, release RST button, then almost immediately boot0)

• Should recognize in Device Manager as "STM Bootloader" device, no COM port assigned

• Choose "Generic STM32F4 series" as board in Arduino IDE

• Choose Board part Number as "BlackPill F411CE"

• Choose upload method as "STM32CubeProgrammer (DFU)"

• Check and upload code (no com port or connection to board required) (Change Code revision to OXCO Type. e.g. "GPSDO - Trimble OCXO")

• Should reboot and start running code after upload complete

• Make sure generic serial is enabled for both USB and USART

• for dst...

• if (gps.time.hour() > 3)   // change time zone
  hours = gps.time.hour() - 4;
  else    
  hours = gps.time.hour() + 20; 
  

GPS Programming

• Download and install U Center
• If needed install driver for CP2102 TTL Module
• Connect Module to GPS (+5V, GND, Rx->Tx, Tx->Rx)
• Connect U Center to TTL Module (Look up COM Port in Device Manager)
• In View->Configuration View Select TP5(Timepulse 5)
• In 0-TIMEPULSE set the following:
  • Freq: 1 Hz
  • Duty Cycle: 50%
  • Lock to GNSS: Checked
  • Other Settings: Checked
  • Align Pulse to TOW=0: Checked
  • Rising Edge: Checked
• Click SEND button
• Select Receiver->Action->Save Config (Does this store permanently or just to capacitor memory?)