si5351-tiny-vfo

VFO build around Si5351, Attiny85, ssd1306

VFO Schematics:

Schematics exactly the same with ZL2PD single band VFO: https://www.zl2pd.com/tiny85_si5351_VFO.html , but without S-meter and SSD1306 OLED 128x64 display used. Actual VFO schematics placed at schematics/schematics.jpg

Brief wiring:

                        Attiny85
                       +----------+   
  ---[RESET]-----------+ PB5  Vcc +---(+)--VCC + 3.3 VOLTS --------
  ---[ENCODER BUTTON]--+ PB3  PB2 +---[I2C/SCL SI5351 / SSD1306]---
  ---[ENCODER LEFT]----+ PB4  PB1 +---[I2C/SDA SI5351 / SSD1306]---
  ---[GROUND]----------+ GND  PB0 +---[ENCODER RIGHT]--------------
                       +----------+
  
  I2C SCL and I2C SDA pull-up to VCC by 4.7 kOhm resistors. 
  ATTINY 85 FUSES set to E:FF, H:DF, L:62
  SI5351 CLK0 output is VFO
         CLK1 output is BFO. 
         SI equipped with 25MHz crystal. If 27Mhz or other will be used you must change XTAL constant in lib/si5351.h

Making project:

make

VFO Operate:

Setup. Enter setup (calibration) mode by pressing ENCODER button at power-on. "#VFO" will be shown at the bottom screen line. Set starting VFO frequency using ENCODER rotation. ENCODER short button pressure change step (100Hz, 1kHz, 5kHz, 1MHz). Long pressure of ENCODER button store starting VFO frequency to EEPROM and go to BFO frequency. At BFO frequency setup #BFO will shown at the bottom screen line. Set BFO frequency exactly the VFO frequency. Long ENCODER button pressure store BFO frequency to EEPROM and return to normal operation mode.

Operation mode. ENCODER rotation change frequency by selected step. ENCODER short button pressure change step (100Hz, 1kHz, 5kHz, 1MHz). Long pressure of ENCODER button (> 5 sec) enter the menu. First menu item is sideband (LSB/USB), rotating encoder select desired sideband. Short ENCODER pressure follow to the next menu item. Second menu item is RIT (Receive independant of Transmit). Value 000 means than receive and transmit frequencies are the same. Rotating ENCODER may change receive frequency from +600 Hz of transmit frequency to -600 Hz. Short ENCODER pressure save all parameters to EEPROM and return to VFO mode.

Credits

Uses SSD1306xLED - Library for the SSD1306 based OLED/PLED 128x64 displays by Neven Boyanov (https://bitbucket.org/tinusaur/ssd1306xled)