SD Card Commands

Commands for SD card file operations. Requires __USE_SD_CARD__ feature enabled.

SD Card Support

The NanoVNA-H supports FAT-formatted SD cards for:

• Saving/loading calibration data
• Storing screenshots (BMP/TIFF)
• Saving measurement data (S1P/S2P)
• Loading command scripts

Note

SD card uses SPI interface sharing the bus with the LCD. File operations pause the sweep during access.

sd_list

List files on the SD card.

Syntax

sd_list [path]

Parameters

Parameter	Description
path	Directory path (optional, default root)

Output Format

<filename>.<ext>  <size>

Examples

ch> sd_list
CAL_001.CAL     6144
SCREEN01.BMP   230454
DATA0001.S2P    12345

ch> sd_list /data
SWEEP001.S1P    8192
SWEEP002.S1P    8192

Notes

• Filenames are 8.3 format (DOS-style)
• Directories shown without size
• Hidden/system files not shown

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sd_read

Read and display file contents.

Syntax

sd_read <filename>

Parameters

Parameter	Description
filename	File to read

Examples

ch> sd_read CONFIG.TXT
# NanoVNA Configuration
sweep 1M 100M 101
power auto
bandwidth 1000

ch> sd_read DATA.S1P
# Hz S RI R 50
1000000 0.998234 -0.023456
2000000 0.997234 -0.024567

Supported File Types

Extension	Content
.TXT	Plain text
.CMD	Command script
.S1P	Touchstone 1-port
.S2P	Touchstone 2-port
.CAL	Calibration data

Binary Files

Binary files (.BMP, .CAL) are output as raw bytes. Not recommended for direct viewing.

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sd_delete

Delete a file from the SD card.

Syntax

sd_delete <filename>

Parameters

Parameter	Description
filename	File to delete

Examples

ch> sd_delete OLDCAL.CAL
deleted

ch> sd_delete SCREEN01.BMP
deleted

Notes

• No confirmation prompt
• Cannot delete directories
• Cannot recover deleted files

Caution

There is no undo for sd_delete. Verify the filename before executing.

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msg

Display a message box on screen from a script (requires __SD_CARD_LOAD__).

Syntax

msg <delay> [text] [header]

Parameters

Parameter	Description
delay	Display duration in milliseconds. Use 0 for indefinite (until touch)
text	Message body text (optional)
header	Message box title/header (optional)

Examples

ch> msg 3000 "Connect OPEN standard" "Calibration"
ch> msg 5000 "Measurement complete"
ch> msg 0 "Press screen to continue" "Paused"

Notes

• Designed for use in .CMD script files to prompt the operator between steps
• The message box blocks script execution until the delay expires or the user touches the screen
• With delay 0, waits indefinitely for a touch event
• Has CMD_RUN_IN_LOAD flag — available in script execution context

Tip

Use msg in calibration scripts to prompt the operator to connect each standard:

sweep 1M 100M 101
msg 0 "Connect OPEN" "Cal Step 1"
cal open
msg 0 "Connect SHORT" "Cal Step 2"
cal short
msg 0 "Connect LOAD" "Cal Step 3"
cal load
cal done
save 0
msg 2000 "Calibration saved"

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File Operations via Menu

The UI provides additional file operations not available via shell:

Saving Files

Menu Path: SD CARD > Save options

Option	Description
SAVE S1P	Save S11 data as Touchstone
SAVE S2P	Save S11+S21 as Touchstone
SCREENSHOT	Save screen as BMP/TIFF
SAVE CALIBRATION	Save calibration to file

Loading Files

Menu Path: SD CARD > LOAD

Browse and select files to load:

• .CAL files: Load calibration data
• .CMD files: Execute command script
• .S1P/.S2P files: Import as stored trace

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Command Scripts

Text files with .CMD extension can contain shell commands:

Script Format

# Comment line
sweep 1M 100M 101
cal open
# wait for user to connect open
cal short
# wait for user to connect short
cal load
# wait for user to connect load
cal done
save 0

Running Scripts

Via menu: CONFIG > EXPERT SETTINGS > LOAD COMMAND SCRIPT

Script Commands

Commands must have CMD_RUN_IN_LOAD flag set:

freq sweep power bandwidth saveconfig clearconfig
cal save recall trace marker edelay s21offset
vbat tcxo reset smooth config usart_cfg usart
vbat_offset transform threshold color measure pause resume

Script Notes

• One command per line
• Lines starting with # are comments
• Blank lines are ignored
• No flow control (loops, conditionals)
• Maximum line length: 64 characters

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File Formats

Touchstone S1P

! Comment
# Hz S RI R 50
1000000 0.998234 -0.023456
2000000 0.997234 -0.024567
...

Touchstone S2P

! Comment
# Hz S RI R 50
1000000 0.998234 -0.023456 0.012345 0.001234 0.012345 0.001234 0.998234 -0.023456
...

Order: S11_re S11_im S21_re S21_im S12_re S12_im S22_re S22_im

Calibration File

Binary format containing properties_t structure.

Screenshot BMP

Standard Windows BMP format:

• 16-bit RGB565 color
• No compression
• 320x240 or 480x320 pixels

Screenshot TIFF

Uncompressed TIFF format:

• 16-bit RGB565 color
• IFD structure

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SD Card Specifications

Supported Cards

Type	Capacity	Notes
SD	Up to 2 GB	Best compatibility
SDHC	4-32 GB	Supported
SDXC	64+ GB	May not work

File System

• FAT16 or FAT32
• 8.3 filename format
• Single partition

Connection

Signal	Pin
CS	PB11
MOSI	PB5 (shared with LCD)
MISO	PB4 (shared with LCD)
SCLK	PB3 (shared with LCD)

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Troubleshooting

Card Not Detected

1. Ensure card is FAT16/FAT32 formatted
2. Try different card (some cards incompatible)
3. Check card is fully inserted
4. Clean contacts

File Access Errors

1. Remove and reinsert card
2. Check filename is 8.3 format
3. Ensure sufficient free space
4. Try reformatting card

Slow Operations

• SD operations share SPI with LCD
• Large files take time to transfer
• Sweep pauses during file access

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Source Code Reference

SD card commands in main.c:

• cmd_sd_list: line 2814 (conditional: ENABLE_SD_CARD_COMMAND)
• cmd_sd_read: line 2832 (conditional: ENABLE_SD_CARD_COMMAND)
• cmd_sd_delete: line 2861 (conditional: ENABLE_SD_CARD_COMMAND)
• cmd_msg: line 2878 (conditional: __SD_CARD_LOAD__)

File system: FatFs/ff.c