- KeyIn: G13-Tip, G15-Ring - to paddle
- KeyOut: G3-Tip, G6-Ring - to radio
- RTC: G8-SDA, G9-SCL - Optional, DS3231 or similar
- Debug: G4-TX, G5-RX - not required for normal use
Mini-CW is a portable CW/Morse keyer and trainer for the M5 Cardputer ADV. The current firmware has a working keyer plus LCWO-inspired trainer modes for Lessons, Words, Callsigns, and Plain Text.
The display is a fixed 240 x 135 text UI:
Top row: current mode
Green separator
6 content rows, 20 characters each
The last content row is often used as a compact status or command hint.
Opt open/close mode select
Ctrl open/close settings for the current mode
Enter start or submit in trainer modes
Backspace edit typed copy
` abort current trainer run, or stop playback/keyer activity
Settings screens use numbered rows. Press the row number to edit a value, type
digits or use , and / to decrease/increase, then press Enter to apply.
Text fields store typed letters as uppercase; use Fn+, and Fn+/ to move the
text cursor left/right while editing. The edit cursor is shown as _. Fn+;
and Fn+. remain available for up/down navigation behavior. Backtick cancels an
edit.
Mode select currently shows:
1 Keyer
2 Lessons
3 Words
4 Calls
5 Plain
6 System
Keyer mode starts on boot. Keyboard CW characters typed on the Cardputer and M1-M5 message
memories append into one TX FIFO on line 6. TX starts after txDelay, or immediately with Enter.
The Keyer top row is a fixed 20-character white status line:
Keyer [keyIn] [keyOut] [WPM]
In paddle modes, WPM is the KeyIn WPM. In straight-key modes, WPM is the
active adaptive SK Wpm.
If Keyer OP lookup has a current match, the top row switches to:
Keyer [name:11] [WPM]
Lines 1-5 show decoded key input history in green. Line 6 shows the remaining TX
FIFO tail, selected status text such as Mute:ON, or Tune state. Sent
characters are removed from the display after they complete.
Tab enter/exit Tune mode
Alt toggle M1-M5 shortcut overlay
1..5 select/send M1-M5 while Alt overlay is active
] raise keyer WPM
[ lower keyer WPM
\ toggle Keyer Mute ON/OFF
Enter start pending TX FIFO now
Backspace edit the unsent FIFO tail
Hold Backspace clear decoded history and TX FIFO
` cancel current TX/playback
Mute suppresses sidetone only; it does not disable keyOut.
Keyer OP lookup reads /fatfs/qsocalls.csv. The CSV is call,name, with pre-normalized
uppercase calls up to 6 characters and names up to 11 characters:
KG6YJ,JUN
N6HAN,HAN
Callsign-like decoded, typed, or message text can update the displayed OP name;
unmatched calls leave the current name unchanged. mycall is ignored. 73,
7 3, 72, or 7 2 clears the displayed OP name.
Press Tab from the Keyer main page to enter or exit it. In Tune mode, paddle tip or ring true-holds tune output through the
current keyOut mode. Press T to start latched tune; press T again, press Tab,
press the paddle, or wait for TuneTimeout to stop it. TuneTimeout:0 disables
the automatic timeout. Other keyboard keys are ignored while Tune is active.
Page 1
1 Vol 0..99
2 Mute ON/OFF, volatile and resets OFF on boot
3 Wpm 5..60
4 Tone 300..999 Hz
5 keyIn Pdl, Pdl-R, SK-T, SK-R
6 keyOut Pdl, Pdl-R, SK, SK-M, OFF
Page 2
1 M1 CQ POTA
2 M2
3 M3
4 M4
5 M5
6 RepeatInt 1..99 seconds, used by repeating M1
Page 3
1 Paddle IambicA, IambicB, Bug
2 txDelay 0..99 seconds
3 TuneTimeout 0..20 seconds, 0 means no timeout
4 myCall AG6AQ (optional, exclude myCall from OP lookup)
5 SK Wpm 5..60, straight-key decoder seed/adaptive saved speed
M1 repeats at RepeatInt after the FIFO drains. Keyboard input or selecting
M2-M5 cancels M1 repeat. M2-M5 are one-shot. A paddle or straight-key press
cancels active or queued message/TX FIFO content.
Lessons mode is Koch-style receive practice. It generates random copy from the active lesson character set, sends it at the configured code/effective speed, and scores typed copy when submitted.
Settings:
1 Lesson 1..40
2 Duration 1..5 minutes
3 Code WPM 5..40
4 Eff WPM 5..40, clamped to Code WPM
5 Group Rand, or 2..7 characters
Words mode runs 25-word adaptive attempts from a built-in English word bank. Correct answers raise WPM, wrong answers lower WPM, and the result tracks score, max WPM, best score, and best max WPM.
Controls:
Enter start/check answer
. replay current word
Backspace edit answer
` abort
Settings:
1 Speed 5..40
2 MinChar 5..40
3 Lesson 9..40
4 MaxLen 2..15
5 MaxWPM 5..40
6 Delay_s 0..5 seconds
Calls mode runs 25-callsign adaptive attempts from a prototype built-in bank.
It accepts letters, digits, and /. Correct answers raise WPM up to MaxWPM;
wrong answers lower WPM.
Controls:
Enter start/check answer
. or Space replay current callsign
Backspace edit answer
` abort
Settings:
1 Speed 5..40
2 MinChar 5..40
3 MaxWPM 5..40
4 Delay_s 0..5 seconds
Plain mode sends one randomly selected built-in plain-text message, accepts typed copy, and scores the result with Levenshtein accuracy after whitespace normalization.
Unlike Words and Calls, period is typed punctuation in Plain mode.
Settings:
1 Code WPM 5..40
2 Eff WPM 5..40, clamped to Code WPM
System mode contains device-wide settings and actions.
1 Volume
2 KeyIn
3 KeyIn WPM
4 Sleep/Batt
5 USB Drive
6 Tone
KeyIn cycles through the available input modes, including paddle,
reverse-paddle, and straight-key modes. USB Drive exposes the FATFS settings
volume to a PC; eject safely, then turn USB Drive OFF or reboot so firmware can
mount the filesystem again.
Pdl G13/Tip = dit, G15/Ring = dah
Pdl-R G13/Tip = dah, G15/Ring = dit
SK-T G13/Tip straight key input, ignore ring
SK-R G15/Ring straight key input, ignore tip
Straight-key decoding starts from saved SK Wpm, adapts to measured key-down
durations, and saves the adapted speed only after it remains stable for about 2
minutes of straight-key use.
KeyOut uses active-low open-drain outputs: G3 is tip and G6 is ring.
Pdl dit to G3/Tip, dah to G6/Ring
Pdl-R dit to G6/Ring, dah to G3/Tip
SK key both G3/Tip and G6/Ring
SK-M key G3/Tip and hold G6/Ring low for MTR
OFF disable keyOut GPIO activity
Lessons, Words, Calls, and Plain currently use firmware-generated or firmware-built-in practice data.
Settings are saved in FATFS as /fatfs/setting.txt. Saved settings include
system volume/tone/keyIn/WPM; Keyer keyOut, paddle, SK Wpm, txDelay,
TuneTimeout, RepeatInt, mycall, and M1-M5; and trainer mode configuration. Keyer Mute is
intentionally not persisted.
Keyer OP lookup data is read from /fatfs/qsocalls.csv. If the file is missing,
firmware creates a header-only call,name file; existing user-managed lookup
files are not overwritten.
Mini-CW uses the shared Mini 8 MB partition layout: one factory app partition
from 0x10000 to 0x500000, and a 3 MB FATFS partition from 0x500000 to
0x800000. FATFS uses 512-byte FATFS/WL sectors for USB MSC compatibility.
FATFS survives normal app reflashes that use this same table, but not
erase_flash, full-chip erase, or another partition layout change. Moving from
the older 0x400000 FATFS layout may cause a one-time FATFS reformat on first
boot.
The build generates build/fatfs.bin from fatfs_image/ and
build/MiniCW_V1_1_Merged_Auto.bin for factory/release flashing. Normal
idf.py flash does not write fatfs.bin, so existing FATFS files survive. The
merged release binary includes the seed FATFS image and overwrites
setting.txt and qsocalls.csv.
The release package can contain MiniCW_V1_1.bin and flash_mini_cw.ps1 in the
same directory. The flash script defaults to COM11 and loads MiniCW_V1_1.bin
from its own directory.
No file-backed word/callsign/plaintext lists yet
Trainer result persistence is not enabled yet
No QSO/logging/statistics mode yet
Callsign bank is prototype data and will be replaced or generated later