Shell Command Overview

The NanoVNA-H provides a command-line shell interface over USB CDC (Virtual COM Port) or serial USART. This page lists all available commands with brief descriptions.

Connecting to the Shell

USB Connection

Connect via USB and open a serial terminal:

• Windows: Use PuTTY, Tera Term, or similar with the COM port
• Linux: screen /dev/ttyACM0 115200 or minicom
• macOS: screen /dev/tty.usbmodem*

Serial Connection

USART1 (PA9 TX, PA10 RX) at configured baud rate (default 115200).

Shell Prompt

ch>

Interactive Command Table

61 commands

All Sweep & MeasurementCalibrationTrace & MarkerConfigurationData ExportSD CardDebug & System

Command	Description	Category	Flags
scan	Perform frequency scan and output data	Sweep & Measurement	mutexbreak
scan_bin *	Binary format frequency scan output	Sweep & Measurement	mutexbreak
freq	Set or query center frequency	Sweep & Measurement	mutexbreakuiload
sweep	Set sweep start/stop/center/span/points	Sweep & Measurement	mutexbreakuiload
power	Set Si5351 output drive strength	Sweep & Measurement	load
offset *	Set IF offset frequency	Sweep & Measurement	mutexuiload
bandwidth	Set measurement bandwidth (sample count)	Sweep & Measurement	load
pause	Pause sweep	Sweep & Measurement	breakuiload
resume	Resume sweep	Sweep & Measurement	mutexbreakuiload
cal	Perform calibration steps (open/short/load/thru)	Calibration	mutex
save	Save calibration to flash slot	Calibration	load
recall	Recall calibration from flash slot	Calibration	mutexbreakuiload
trace	Configure trace format, channel, enable/disable	Trace & Marker	load
marker	Set marker position and properties	Trace & Marker	load
edelay	Set electrical delay compensation	Trace & Marker	load
s21offset	Set S21 port-through offset (dB)	Trace & Marker	load
smooth *	Set trace smoothing level	Trace & Marker	mutexbreakuiload
transform *	Configure time domain transform	Trace & Marker	load
config *	Set device configuration options	Configuration	mutexbreakuiload
saveconfig	Save current configuration to flash	Configuration	load
clearconfig	Reset configuration to factory defaults	Configuration	load
tcxo	Set TCXO reference frequency for calibration	Configuration	load
threshold	Set harmonic frequency threshold	Configuration	load
vbat	Read battery voltage	Configuration	load
vbat_offset *	Calibrate battery voltage ADC offset	Configuration	load
color *	Set trace/UI color palette	Configuration	load
time *	Set or read RTC date/time	Configuration	ui
usart_cfg *	Configure serial port parameters	Configuration	mutexbreakuiload
usart *	Send data via serial port	Configuration	mutexbreakuiload
data	Output measured S-parameter data	Data Export
frequencies	Output sweep frequency list	Data Export
capture	Output screen capture as bitmap	Data Export	mutexbreakui
gamma	Output raw gamma (reflection coefficient) data	Data Export
sample *	Output raw ADC samples	Data Export
dump *	Dump raw memory/register data	Data Export	mutexbreak
measure *	Run measurement module (LC/crystal/filter/cable)	Data Export	mutexbreakuiload
sd_list *	List files on SD card	SD Card	mutexbreakui
sd_read *	Read/execute file from SD card	SD Card	mutexbreakui
sd_delete *	Delete file from SD card	SD Card	mutexbreakui
msg *	Display message on screen from SD script	SD Card	mutexbreakload
reset	Reset the device	Debug & System	mutexbreakload
help	List available commands	Debug & System
version	Show firmware version	Debug & System
info *	Show device information and build details	Debug & System
test *	Run hardware self-test	Debug & System
stat *	Show sweep timing statistics	Debug & System	mutex
threads *	Show ChibiOS thread status	Debug & System
port *	Select audio codec input port (TX/RX)	Debug & System	load
touchcal	Calibrate touchscreen	Debug & System	mutexbreak
touchtest	Test touchscreen input	Debug & System	mutexbreak
dac *	Set DAC output value	Debug & System	load
gain *	Set codec analog gain	Debug & System	mutex
i2c *	Raw I2C bus operations	Debug & System	mutex
si *	Write Si5351 registers directly	Debug & System	mutex
lcd *	LCD controller commands	Debug & System	mutex
b *	Show/set frequency band configuration	Debug & System	mutex
t *	Configure Si5351 timing parameters	Debug & System	mutex
i *	Configure I2C bus timing parameters	Debug & System	mutex
refresh *	Send screen framebuffer to PC	Debug & System	mutexbreakui
touch *	Simulate touch press at coordinates	Debug & System	mutexbreakui
release *	Simulate touch release	Debug & System	mutexbreakui

* Requires compile-time feature flag (hover for details) mutex Acquires sweep mutex break Interrupts sweep ui Runs from UI thread load Runs during SD load

Command Quick Reference

Sweep and Measurement

Command	Description	Page
scan	Perform sweep, output data	Sweep
scan_bin	Binary output scan	Sweep
freq	Set/get CW frequency	Sweep
sweep	Set/get sweep range and points	Sweep
power	Set/get output power	Sweep
bandwidth	Set/get IF bandwidth	Sweep
pause	Pause sweep	Sweep
resume	Resume sweep	Sweep

Calibration

Command	Description	Page
cal	Calibration operations	Calibration
save	Save calibration to slot	Calibration
recall	Load calibration from slot	Calibration

Trace and Marker

Command	Description	Page
trace	Configure traces	Trace/Marker
marker	Configure markers	Trace/Marker
edelay	Set electrical delay	Trace/Marker
s21offset	Set S21 offset	Trace/Marker
transform	Time domain settings	Trace/Marker
smooth	Data smoothing	Trace/Marker

Configuration

Command	Description	Page
config	Get/set configuration	Configuration
saveconfig	Save configuration to flash	Configuration
clearconfig	Reset configuration	Configuration
tcxo	Set TCXO frequency	Configuration
threshold	Set harmonic threshold	Configuration
vbat	Read battery voltage	Configuration
vbat_offset	Set battery offset	Configuration
color	Set display colors	Configuration
usart	Serial console control	Configuration
usart_cfg	Serial port configuration	Configuration
time	RTC date/time	Configuration
touchcal	Touch screen calibration	Configuration
touchtest	Touch screen test	Configuration

Data Export

Command	Description	Page
data	Output measured data	Data Export
frequencies	Output frequency list	Data Export
capture	Screen capture (binary)	Data Export
dump	Dump raw ADC samples	Data Export
measure	Measurement results	Data Export

SD Card

Command	Description	Page
sd_list	List SD card files	SD Card
sd_read	Read SD card file	SD Card
sd_delete	Delete SD card file	SD Card

Debug and System

Command	Description	Page
info	Device information	Debug
version	Firmware version	Debug
help	List commands	Debug
reset	Reset device	Debug
threads	Thread info (debug)	Debug

Remote Desktop

Command	Description	Page
refresh	Get screen data	Debug
touch	Simulate touch	Debug
release	Simulate touch release	Debug

Command Flags

Commands have execution flags that control when they can run:

Flag	Description
CMD_WAIT_MUTEX	Must run in sweep thread with mutex
CMD_BREAK_SWEEP	Interrupts ongoing sweep
CMD_RUN_IN_UI	Can run while UI is processing
CMD_RUN_IN_LOAD	Can run from SD card script

Complete Command List

All commands available in firmware v1.2.44:

scan scan_bin data frequencies freq sweep power bandwidth
time sd_list sd_read sd_delete saveconfig clearconfig dump
touchcal touchtest pause resume cal save recall trace marker
edelay s21offset capture measure refresh touch release vbat
tcxo reset smooth config usart_cfg usart vbat_offset transform
threshold help info version color

Note

Some commands are only available if corresponding features are enabled at compile time. Debug commands (threads, test, stat, gain, si, i2c, lcd, band) are typically disabled in release builds.

Shell Syntax

General Format

command [arg1] [arg2] [arg3] [arg4]

Maximum 4 arguments, 64 characters per line.

Frequency Format

Frequencies can be entered as:

• Plain number: 1000000 (1 MHz)
• With k suffix: 1000k (1 MHz)
• With M suffix: 1M (1 MHz)
• With G suffix: 1.5G (1.5 GHz)

Numeric Arguments

• Integers: 101, 4000
• Floats: 1.5, -3.2
• Hex: 0xFF

Example Session

ch> info
Board: NanoVNA-H
2019-2025 Copyright NanoVNA.com
Version: 1.2.44

ch> sweep 1M 100M 101
ch> cal open
ch> cal short
ch> cal load
ch> cal done
ch> save 0
ch> data 0
0.001234 0.005678
0.001245 0.005689
...
ch> pause
ch> resume

Source Code Reference

Command definitions are located in:

• Command table: main.c lines 2912-3033
• Command implementations: main.c (various locations)
• Shell processing: main.c lines 3050-3200