The functionality of the QCX kit depends greatly on the firmware in the microcontroller. Since the launch if the QCX kit in August 2017, there have been a number of new versions providing more functionality and sometimes including bug fixes. The firmware version files are hosted by the QRP Labs groups.io forum. An inexpensive AVR programmer can be used to upgrade your firmware version, or you can buy the latest firmware chip from QRP Labs.

Upgrading your firmware

The QCX kit includes a 2 x 3-pin standard AVR header for In-Circuit-Programming on the board. Many suitable AVR programmers are available inexpensively on eBay and elsewhere. They have a USB cable to connect to a PC. On the PC you need software such as avrdude (very popular command line driven tool), or Windows programs with graphical user interfaces to avrdude.exe, for example Extreme Burner, Bit Burner, or AVRDudess. All are free. When upgrading the firmware, ensure:

1) Only use an original QRP Labs QCX firmware chip
2) Program only the provided .hex file (see above); do not change the Fuse settings, or other memories (e.g. EEPROM). 

CLICK HERE for a tutorial written by Simon VK3ELH on how to use an Arduino UNO and the AVRDudess program to update your QCX firmware. 

Version history

Version Date Features
1.02 06.Nov.2019 - Eliminate the faint "Woodpecker" clicking when S-meter active, tuning or CW decoder updates
- Eliminate click at start end end of sidetone audio burst (that was due to sudden change in DC bias)
- Can now operate sending stored messages while the RIT or Speed adjustment is active
- Now can handle either a 25MHz or a 27MHz reference crystal and calibrate properly in both cases
- Tune rate and RIT rate cursors can now be moved by rotary encoder push-and-turn (within 0.3s)
- Remove small click that occurred when exiting the menu system
- Bug fix: On GPS detect, which automatically sets Practice mode to protect PA. Now stops immediately
- Bug fix: S-meter was STILL disappearing, if CW decoder was switched off
- Bug fix: Battery icon was corrupted after editing any text parameter in the menu system
- Bug fix: On exit/disable beacon, can't use stored message sending features until next beacon start passed
- Bug fix: Listed tune rates in 3.4 not all available. now allows 1MHz, 100kHz, 10kHz, 1kHz, 500Hz, 100Hz or 10Hz
- Bug fix: RIT rate in menu 3.6 allows 10kHz steps which are not possible (RIT display is maximum +/- 9,999Hz)
1.01a 08.Oct.2019 - Bug fix: Decoder didn't work during menu editing and self-decoding your own transmission
1.01 07.Oct.2019 - Allow transmission while RIT adjustment is active
- Allow transmission while keyer speed adjustment is active
- Copy VFO A to B by Right button long press then Right button short press (within 1 second)
- Copy VFO B to A by Right button long press then Right button double press (within 1 second)
- Switch off DSP during transmit, improves responsiveness of keyer (DSP is not used during transmit)
- Break character -...- changed from | to = on display
- Dynamic calculation of Si5351A divisor rather than from a table based on band; enables changing band by preset freq
- Remove menu 3.9 (Band) - no longer relevant
- When in practice mode, 'P' is now displayed to the right of the frequency on the top row
- New menu 4.10 "Strght mode", choice of Both/Tip/Ring (so mono jacks can work)
- New menu 7.8 "Custom splsh", enables message 11 & 12 to be used as splash screen on power up (Factory reset is now 7.9)
- Automatic protection against GPS keying the transmit; when GPS detected, automatically enters practice mode
- WSPR encoding now re-encodes WSPR one transmit cycle sooner, in cases where the Maidenhead grid changed
- Bug fix: IAMBIC A mode keyer bug
- Bug fix: Disappearing S-meter after changing some unrelated parameters in the menu
- Bug fix: When CW decoder and S-meter both enabled, some digits of frequency display could get corrupted
- Bug fix: Tuning while keying resulted in loud tone in headphones. Tuning during key-down is now disabled
- Bug fix: Incorrect built-in bias caused CW decoder to track sending speed faster than it really was. Fix improves decoder
1.00g 22.Jan.2019 - Bug fix: Remove sudden start to keying RF envelope; it did not start at zero amplitude (problem is worse at very high keying speeds)
1.00f 01.Aug.2018 - Display "Si5351A Error" rather than blank screen, in the event of Si5351A failure
- Toggle LCD D5 during "Band Select" as a diagnostic
- Increase I-Q balance and Phase Lo/High configuration frequencies by 1 digit (Allows 1500Hz offset alignment)
- Bug fix: Sometimes corruption in initialization of tuning and rit rate
1.00e 07.Dec.2017 - Bug fix: stored message sending now sends at current keyer speed (not stored default)
- Bug fix: WSPR tones in the second half of the transmission were potentially corrupted
1.00d 19.Nov.2017 - Bug fix: During CW message sending, the displayed frequency was the beacon frequency, not VFO
- Bug fix: CW-R mode did not work (receiving on the lower sideband rather than usual upper)
1.00c 18.Oct.2017 - Bug fix: auto-character spacing feature did not work properly after version 1.00b
- Bug fix: display showed VFO frequency not WSPR transmit frequency, after a GPS calibration
- Bug fix: WSPR did not transmit reliably in every slot, sometimes it did, sometimes not
1.00b 06.Sep.2017 - Several keyer improvements particularly to Mode B
- Bug fix: transmit decode did not work well in Straight mode (bug introduced in 1.00a)
- Bug fix: prevent horrible loud noise sometimes if you enter menu while key is pressed
- Bug fix: prevent right key very long press sometimes causing loud sidetone & low power out
- Bug fix: stored message sending always sent the first message, regardless of selection
- Bug fix: CW decoder did not work properly while editing menu items
- Bug fix: When sending a stored message, the first character could be corrupted
1.00a 28.Aug.2017 - CW Offset configuration parameter now accepts an additional digit, e.g. 1500Hz for WSPR reception
- More frequent polling of paddle inputs (worst case interval is now 66us)
- Bug fix: Remove huge painful thump on power-up, and on exiting the configuration menu
- Bug fix: sidetone issue with random alternating high/low volume when sidetone volume was not 99
- Bug fix: sidetone volume trailing off over the course of a few seconds
- Bug fix: After factory reset, next time you entered the menu you were in item 7.1, rather than 1.
- Bug fix: "Save settings" did not work properly
1.00 21.Aug.2017 - First release version, for the launch of the QCX kit on 21-Aug-2017
Y1.00 01.Aug.2017 - YOTA summer camp buildathon version - considerably improved for the first official general release version