Hi,

I just finished building a QCX-Mini with the uSDX mod for 20m (and TCXO). Unfortunately, the display only shows a single (top) row of blocks. I checked all things in the troubleshooting section [1] and that didn't help, also I checked the connection for the LCD pins with a DVM between the uC socket and the LCD, all was fine. So in conclusion, I think the uC is not starting correctly. Probably because I did something wrong while flashing the uC with the firmware for the uSDX. I flashed ist with the avrdude -e switch, which probably also erases some thing I still needed, like a fuse or eeprom or whatever.

So, what I did: - checked everything in the assembly manual again, I'm "pretty sure" there is no mistake - checked the 5 and 12V rails, both are good. - 20MHz crystal is starting (checked with oscilloscope) - LCD_D4-D7 are doing "something", checked with the osci

what was a bit out of the ordinary: - LCD_EN only is high for a very short amount of time, far less than a single bit on LCD_D4 to D7.

so, I'm a bit confused. Just to be sure, does anyone have the fuse settings for the atmel uC in avrdude? I tried setting the ones from [2], but while setting the efuse I got this:

avrdude -c avrispmkII -p m328p -U efuse:w:0x04:m

avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.00s

avrdude: Device signature = 0x1e950f (probably m328p)
avrdude: reading input file "0x04"
avrdude: writing efuse (1 bytes):

Writing | ################################################## | 100% 0.01s

avrdude: 1 bytes of efuse written
avrdude: verifying efuse memory against 0x04:
avrdude: load data efuse data from input file 0x04:
avrdude: input file 0x04 contains 1 bytes
avrdude: reading on-chip efuse data:

Reading | ################################################## | 100% 0.00s

avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x0000
         0xfc != 0x04
avrdude: verification error; content mismatch

avrdude: safemode: efuse changed! Was 4, and is now fc
Would you like this fuse to be changed back? [y/n] y
avrdude: and COULD NOT be changed
avrdude: safemode: Fuses not recovered, sorry

avrdude done.  Thank you.

I'm very open for any ideas of how to troubleshoot this. I think the LCD isn't working because LCD_EN isn't high for long enough, but what could possibly cause that?

[1] https://qrp-labs.com/qcxmini/trouble.html

[2] https://groups.io/g/QRPLabs/files/AVRDude%20Programmer%20settings%20for%20Atmega%20328-PU

for the ppl finding this at some point with google:

So, I decided to have a look at the uSDX sources [1], and in line 67 it already tells me the fuses. programmed them with avrdude, now it starts. I'm not sure thats the code running on my device [2], but it works now.

[1] https://github.com/threeme3/QCX-SSB/blob/master/QCX-SSB.ino [2] https://dl2man.de/wp-content/uploads/2020/12/QCX_TXCO.ino_.with_bootloader.standard.zip

thanks, but as I wrote, I already fixed it. sorry for posting in the wrong group.