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 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
1.00g 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