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AVR ICE-Cube - Manually Loading Software

The AVR ICE-Cube automatically activates the built-in Flash Loader when you first use it and when AVR Studio tells it to update its software.  In most cases, it is unnecessary to manually load software.  Even so, the capability exists and will be described on this page.  You may want to use it to load the Atmel software corresponding to a specific version of AVR Studio.  You can also erase the Atmel software, which you may decide to do if you sell your AVR ICE-Cube so that it will be in the state in which it was shipped to you by ECROS Technology.

Activating the Flash Loader

To manually load software into the AVR ICE-Cube, you need to activate the built-in Flash Loader and then use AVR Prog in the normal way.  The Flash Loader can be activated by applying power to the ICE-Cube while a special "boot" pad is shorted to ground.  You will find this boot pad close to where the serial cable terminates on the ICE-Cube.  Refer to the picture at right.  Move your mouse cursor over it to zoom in on the exposed boot pad.  A ground connection almost completely surrounds it and is also exposed.

You will need to short the pad to the ground connection around it using some small, electrically conductive object.  Suitable items for this purpose are an electrician's screwdriver, an unfolded paper clip, etc.  Don't use a ball-point pen because the ink will dry on the pad and make it difficult to do this again later.

Connect the AVR ICE-Cube to a target system with the power turned off.  Apply and hold the short circuit and then turn the power on.  Remove the short circuit.  If only the green LED comes on, you have succeeded in activating the Flash Loader.  Recall that normally both the green and red LEDs come on when the ICE-Cube powers up.  If this happens, your short circuit did not take.  It is fine to try again, but make sure to remove the short circuit before removing power.  It is not a good idea to have the boot pad shorted during power-down (read Brown-Outs and Power Down, below, if you need to know why).

Loading Software

Now that you have the Flash Loader active, you can start AVR Prog to load new software into the AVR ICE-Cube.  The process is exactly the same as loading software before the first use, so if necessary refer to the instructions given elsewhere for that case.

Erasing the AVR ICE-Cube Software

You can erase the software in your AVR ICE-Cube, which will return it to the condition in which it was shipped to you from ECROS Technology.  To do this, start AVR Prog and click the Advanced... button in the AVRprog control dialog.  In the new dialog, you will find an Chip Erase button.  Click it.  The Flash Loader is not erased, only the Atmel software.  Close the Advanced dialog by clicking the Close button and the AVRprog control dialog by clicking the system Close button.  Power down the ICE-Cube.

To reload software, just power up the ICE-Cube and the Flash Loader will run (see First Use).

Click this button to go back to the AVR ICE-Cube introduction.

Brown-Outs and Power Down

As stated above, it is not a good idea to power down the AVR ICE-Cube while the boot pad is shorted to ground.  This paragraph explains why.  The ICE-Cube has very strong AC isolation from the target system's power rail so as to avoid interference in either direction.  This consists of a series inductor and several decoupling capacitors.  When target power is turned off, the ICE-Cube power rail voltage falls gradually but the current drawn by the ICE-Cube drops abruptly when the LEDs cease conducting and various other circuits turn off.  When this happens, the series inductor can cause the supply voltage to blip back up again.  This can cause the MCU on the ICE-Cube to reboot and try to start executing software again.  This is harmless if the software it tries to execute is the normal Atmel JTAG interface software.  However, if it is the Flash Loader it is possible for undesirable writes to Flash to occur.  In particular, it has been found that fuses can be written such that you cannot re-program the ICE-Cube.  This problem could, perhaps, be avoided if the brown-out detection fuse were programmed.  However, as the MCU can usually operate below the lowest brown-out level, the design decision was made not to program this fuse so as to allow the ICE-Cube to be used at lower target system voltages.  In summary, then, to stay out of trouble only use the manual procedure for activating the Flash Loader when it is really necessary and remove the boot pad short circuit before removing power.