MCU Boot Loader Troubleshooting
When MCU firmware load is interrupted, or the power-on firmware checksum test fails, the KX3 enters its bootstrap loader.
You can also
force the KX3 to enter its bootstrap loader
by turning the KX3 on with a 10-second press and hold of the two POWER buttons (BAND- and ATU Tune).
The MCU boot loader displays MCU LD on the KX3 front panel display.
The display may not be backlit.
To load KX3 firmware, follow these steps in sequence:
-
Turn your KX3 off by switching off or unplugging its power supply, including internal batteries.
The KX3's microcontroller may continue to run at very low voltage, and it must start from a power-on reset.
Disconnect any other connectors that have any possibility of providing power to the KX3.
A very small leakage current from another device might be enough to keep the MCU from completely resetting.
Wait 30-60 seconds before turning power back on.
-
If the
KX3 Utility
is running, select its
Port
tab, then close the
KX3 Utility, by clicking
Exit
or the red X at the top right of the main window.
The
Port
tab provides the clearest indication of a successful connection when the
KX3 Utility
is subsequently started.
-
If you are using a software sharing program such as
N8LP's LP-Bridge or microHAM's Router
between your personal computer and your KX3's serial port,
change the cabling so that the PC is connected directly to the KX3 without an intervening software "forwarder".
These programs send
K3 and KX3 Programmer's Reference
commands, and a KX3 in its bootstrap loader isn't able to process those commands.
Some commands may put the KX3 bootstrap loader into an unresponsive state.
-
Restart (reboot) the personal computer that will run the
KX3 Utility.
This isn't often necessary, but occasionally a serial port or USB device driver doesn't properly close.
Rebooting reinitializes the device and its driver.
-
Connect your KX3 to its power supply, then press and hold the
two KX3 power buttons (BAND- and ATU TUNE) for 10 seconds, until you see
MCU LD
on the KX3 front panel display (without backlighting).
The red Tx light should be blinking.
Release the power buttons.
-
Start the
KX3 Utility
and navigate to its
Port tab.
The
KX3 Utility
should discover the KX3 at 38,400 bit/s.
If the
Port
tab has been selected, you should see a dialog that looks something like this:
If you don't see this dialog, try clicking the
Test Communications button.
The
KX3 Utility
cannot load firmware if it does not receive responses.
Information in
USB to Serial Adapter Troubleshooting may help to resolve this issue.
The problem might be serial port cabling, an incorrect COM port choice, a problem with the Personal Computer,
or a damaged KX3 serial port.
Incorrect COM port choice is a common problem here.
Sometimes USB to Serial Adapter device drivers change the COM port number unexpectedly.
- When you see this dialog, press its OK button to continue.
-
Firmware load can take quite a long time if the View Menu
Trace
menu item is checked.
Uncheck Trace unless you require this diagnostic information.
-
Select the
Firmware
tab, and click
Send All New Firmware to KX3.
If the send buttons are disabled, view
Troubleshooting: Send Buttons Disabled.
-
The
KX3 Utility
should send MCU firmware to your KX3, followed by any other "new" firmware required.