Author Topic: LEGO IR Tower as hardware programmer for Axon  (Read 3387 times)

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Offline tjumpTopic starter

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LEGO IR Tower as hardware programmer for Axon
« on: November 09, 2008, 10:08:15 PM »
I would like to use my LEGO serial IR towers as my hardware programmers for my Axon uCs. How can this be done?

Note: for an explanation for why I want to do this read on, but I know some would rather know the issue up front rather than read through a long descriptive before getting to the root question.

Anyway...I run a high school engineering program of which the LEGO MINDSTORMS kit and RCX have been a major component. We have also used the MIT HandyBoard. Both of these uCs have hardware programmers (LEGO - IR communication with uC; HB - RJ11 cable communication with uC). In both cases I can isolate the process of programming and downloading to the uCs from student access to the Windows interface. IOW, I have security settings that block student access to Windows functions such as right click, saving to the C drive, changing settings, etc. The students have no physical access either (usb, floppy, dvd drives are not accessible) to protect from hacking into and changing settings. If any of you work with students you may understand my need to keep students restrained to applications only, and out of the underlying operations of the computers. With 200 students, each with their own idea of how computers should be set up, making changes at will; it does not take long until systems crash and I, as the instructor, can't teach because each workstation needs to be managed differently. Having a set system is critical. So, having a hardware programmer that restricts access is also critical.

With the LEGO serial towers necessary for the RCX, and with almost zero failures with the serial towers (the usb towers lose connection with the host pc periodically and I need to unlock the cabinets and unplug/replug the towers to reactivate them...a real pain. Thus my use of the serial towers.) if I can use the towers for both the RCX and the Axon it would make life that much cleaner than having to introduce another piece of hardware into the system; and the use of the bootloader gives access to an open usb port.

Anyway, if there are some thoughts here; or someone that could write the code for me I would be ecstatic!!

T. Jump

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Re: LEGO IR Tower as hardware programmer for Axon
« Reply #1 on: November 11, 2008, 10:36:00 PM »
So what you are asking for is a wireless bootloader?

I glanced around about the serial tower and it appears you might have some problems:

Whatever device you use, on the Axon side you need to do two things.

First, you need an IR receiver that outputs TTL based serial (not RS232 serial) to the Axon. The datasheet of your device should say which.

Second, you need to modify the Axon bootloader. First, look at the Axon bootloader software and change the port from USB to one of the other UART pins. It might take a bit of datasheet staring, but its a fairly easy mod. Save, compile, and upload it to the Axon. To do so, you need to buy an AVR hardware programmer to upload the new bootloader. After you upload the new bootloader once, you won't need the hardware programmer again.

I'm sure you'll have more questions because I didn't go into detail, so feel free to post again when you get lost/stuck.

And here is a tutorial for setting up the bootloader I use:


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