Feature Flags

Complete reference for compile-time feature flags defined in nanovna.h.

Mixer Variant Selection

//#define __MS5351__    // Original MS5351 synthesizer
#define __ZEETK__       // ZeeTK NE602A mixer (default)

Flag	Effect
`__ZEETK__`	ZeeTK NE602A mixer support, lower minimum frequency (600 Hz), threshold 300 MHz
`__MS5351__`	Original MS5351/SA612A, minimum 1600 Hz, threshold 290 MHz

Display Configuration

LCD Driver Selection

// F303 (NanoVNA-H4)
#define LCD_DRIVER_ST7796S
#define LCD_480x320

// F072 (NanoVNA-H) - auto-detect
#define LCD_DRIVER_ILI9341
#define LCD_DRIVER_ST7789
#define LCD_320x240

Display Features

Flag	Description	Default
`__USE_DISPLAY_DMA__`	DMA mode for LCD writes	Enabled
`__LCD_BRIGHTNESS__`	Brightness control menu	F303 only
`__FLIP_DISPLAY__`	Allow 180-degree rotation	Enabled
`_USE_SHADOW_TEXT_`	Shadow on plot text	Enabled
`__VNA_FAST_LINES__`	Faster line drawing	Disabled

Core Features

Flag	Description	Default
`__DFU_SOFTWARE_MODE__`	Enter DFU from menu/command	Enabled
`__USE_RTC__`	Real-time clock support	Enabled
`__USE_BACKUP__`	RTC backup registers	Enabled
`__USE_SD_CARD__`	SD card file operations	Enabled
`__USB_UID__`	Unique USB serial string	Enabled
`__USE_SERIAL_CONSOLE__`	Serial port console	Enabled
`__USE_GRID_VALUES__`	Show Y-axis values	Enabled
`__REMOTE_DESKTOP__`	Remote control support	Enabled
`__USE_SMOOTH__`	Data smoothing option	Enabled
`__DIGIT_SEPARATOR__`	Configurable decimal separator	Enabled

Math and DSP

Flag	Description	Default
`__VNA_USE_MATH_TABLES__`	Precomputed sin/cos tables	Enabled
`__USE_VNA_MATH__`	Fast math approximations	Enabled
`USE_FFT_WINDOW_BUFFER`	Cache FFT window function	Disabled
`__USE_DSP__`	Cortex-M4 DSP instructions	F303 only

Math Table Details

When __VNA_USE_MATH_TABLES__ is enabled:

512-entry sin/cos table
Maximum error: 4e-7
Also used for FFT calculations
Saves significant flash space

Measurement Module

#define __VNA_MEASURE_MODULE__    // Master enable

When enabled, additional flags become available:

Flag	Description
`__USE_LC_MATCHING__`	L/C matching calculator
`__S21_MEASURE__`	S21 component measurements
`__S11_CABLE_MEASURE__`	Cable length/loss (S11)
`__S11_RESONANCE_MEASURE__`	Resonance finder (S11)

Measure Modes

enum {
  MEASURE_NONE = 0,
  MEASURE_LC_MATH,         // LC matching network
  MEASURE_SHUNT_LC,        // Shunt LC component
  MEASURE_SERIES_LC,       // Series LC component
  MEASURE_SERIES_XTAL,     // Crystal parameters
  MEASURE_FILTER,          // Filter characterization
  MEASURE_S11_CABLE,       // Cable length/loss
  MEASURE_S11_RESONANCE,   // Resonance frequency
  MEASURE_END
};

SD Card Submodules

When __USE_SD_CARD__ is enabled:

Flag	Description	Default
`__SD_CARD_LOAD__`	Load config.ini on boot	Enabled
`__SD_CARD_DUMP_TIFF__`	TIFF screenshot format	Enabled
`__SD_CARD_DUMP_FIRMWARE__`	Dump firmware to SD	Enabled
`__SD_FILE_BROWSER__`	File browser UI	Enabled

Capture Formats

Flag	Description
`__CAPTURE_RLE8__`	RLE8 compressed capture format

Advanced Features

Flag	Description	Default
`__VNA_Z_RENORMALIZATION__`	Port-Z renormalization	Disabled
`USE_VARIABLE_OFFSET`	Runtime IF frequency table	Enabled
`USE_VARIABLE_OFFSET_MENU`	IF selection menu	Enabled

Debug Features

These flags enable additional shell commands for debugging.

Flag	Command	Description
`ENABLE_THREADS_COMMAND`	`threads`	Thread information
`ENABLE_STAT_COMMAND`	`stat`	System statistics
`ENABLE_GAIN_COMMAND`	`gain`	Codec gain control
`ENABLE_TEST_COMMAND`	`test`	Hardware tests
`ENABLE_I2C_COMMAND`	`i2c`	I2C bus access
`ENABLE_LCD_COMMAND`	`lcd`	LCD controller access
`ENABLE_SI5351_REG_WRITE`	`si`	Si5351 register access
`ENABLE_BAND_COMMAND`	`band`	Manual band override
`ENABLE_SAMPLE_COMMAND`	`sample`	Raw sample values
`ENABLED_DUMP_COMMAND`	`dump`	Raw ADC dump

Hardware Constants

Frequency Limits

// Minimum frequency (depends on mixer)
#ifdef __ZEETK__
#define FREQUENCY_MIN            600      // 600 Hz
#else
#define FREQUENCY_MIN            1600     // 1600 Hz
#endif

// Maximum frequency
#define FREQUENCY_MAX            2000000000U  // 2 GHz

// Harmonic threshold
#ifdef __ZEETK__
#define FREQUENCY_THRESHOLD      300000110U   // 300 MHz
#else
#define FREQUENCY_THRESHOLD      290000110U   // 290 MHz
#endif

Sweep Points

// F303 target
#define SWEEP_POINTS_MAX         401
#define SWEEP_POINTS_MIN         21

// F072 target
#define SWEEP_POINTS_MAX         101
#define SWEEP_POINTS_MIN         21

Audio Configuration

#define AUDIO_ADC_FREQ_K        192     // ADC rate in kHz
#define AUDIO_SAMPLES_COUNT     48      // Samples per measurement
#define FREQUENCY_IF_K          12      // IF frequency in kHz

Defined automatically for STM32F072:

#define ARM_MATH_CM0
// No FPU
// No __USE_DSP__

Defined automatically for STM32F303:

#define NANOVNA_F303
#define ARM_MATH_CM4
#define __USE_DSP__
// FPU available (hard float)

Enabling Features

To enable a disabled feature:

Open nanovna.h
Uncomment or add the desired #define
Rebuild firmware

Example:

// Enable Z renormalization
#define __VNA_Z_RENORMALIZATION__

// Enable fast line drawing
#define __VNA_FAST_LINES__

Feature Dependencies

__USE_SD_CARD__
├── __USE_RTC__ (required for timestamps)
├── __SD_CARD_LOAD__
├── __SD_CARD_DUMP_TIFF__
├── __SD_CARD_DUMP_FIRMWARE__
└── __SD_FILE_BROWSER__

__VNA_MEASURE_MODULE__
├── __USE_LC_MATCHING__
├── __S21_MEASURE__
├── __S11_CABLE_MEASURE__
└── __S11_RESONANCE_MEASURE__

USE_VARIABLE_OFFSET
└── USE_VARIABLE_OFFSET_MENU

__LCD_BRIGHTNESS__
└── __VNA_ENABLE_DAC__ (H4 uses DAC for brightness)

Build-Time Defines

Set via Makefile UDEFS:

# F303 build
UDEFS = -DARM_MATH_CM4 -DVERSION=\"$(VERSION)\" -DNANOVNA_F303

# F072 build
UDEFS = -DARM_MATH_CM0 -DVERSION=\"$(VERSION)\"

# RTC source selection
UDEFS+= -DVNA_AUTO_SELECT_RTC_SOURCE
# Or force LSE:
# UDEFS+= -DVNA_USE_LSE