OpenServo.com

[Jan]

Hi all,

is there a FAQ or some kind of how-to guide that details the build process of the AVR firmware? I've downloaded the hourly snapshot, but I can't compile the software out of the ATmega8 AVRStudio project file.

[mpthompson]

Hi Jan,

Unfortunately the ATmega8 has never been very well maintained. When I did the original port early last year I did build an ATmega8 OpenServo so it did work at one time. However, since then I don't think there has been much interest in the ATmega8 port because we could see that the feature set would eventually outgrow 8K flash. I would strongly suggest that you stick with the ATmega168 version as that is the chip being used for actively for OpenServo development at this time.

I'll see if I can get the ATmega8 version going again and post a follow up to this thread. I'll also review the documentation on the site and in the README's over the next two days and see what I can make some short-term improvements regarding building the firmware. In the meantime, if you have Yahoo! messenger you can IM me at michael_peter_thompson and I'll try to give you any real-time help that I can. Just remember I'm on Pacific time in the US which is about 8 to 9 hours behind Germany.

-Mike

[Jan]

Hi Mike,

thank you for your help, but I changed my plans. I've ordered 20 pieces of the Mega168, because I don't want to put a lot of work into an outdated design.

I always thought the advantage of cvs systems to be in the possibility to keep every published version of the code available? But this is just my kind of naive view, because I never really used CVS software.

My WInCVS client refuses to work, I guess there's something wrong with my python setup. Whatever, I'll figure that out later.

Do you have an idea, during which period the Mega8 version was up and running, so I might try to get all the files from that date? As I have some Mega8 in DIP packages, it would be nice to do some breadboard experiment.

Regards,

Jan

[Jan]

Now the compilation process completes without errors or warnings. I can build the software for each variant, mega8, mega88 and mega168. I added some defines for the mega88 in the bootloader prog.c file and put together a new project configuration supporting the 8 kB devices.

I'm now going to build the circuit on breadboard to test it. I'm so curious if it will work

Jan

[mpthompson]

Hi Jan,

I see you are beating me to this. I was just about to start looking into this when I saw your message this morning. Hopefully you will find it does indeed work .

If not, you know where to find us...

-Mike

[Jan]

Hi,

I just wanted to tell you that it is working fine. The firmware is running on an ATmega8.

For testing, I use a L293 H bridge, because it is easier on the breadboard. The voltage drop of this device is rather bad, but I've built the system just for testing the software, not for the evaluation of hardware characteristics, so the voltage drop is not important anyway.

I'm using the OSIF to control the servo, and I have to say that this is a great tool. It's cheap to build and the PC software makes exprimenting with the servo easy. I really like the "scan bus" function, it's ideal to test the bus wiring.

Thanks a lot to Mike and Barry for helping me.

Regards,

Jan

[mpthompson]

Jan,

Good news indeed. I'm glad you are finding the pieces coming together for you.

-Mike

[youthreewire]

[Arnold60]

Implementing a USB CDC device with V-USB violates some aspects of USB 1.1. CDC-Mode may therefore fail or be unreliable on some operating systems or computer hardware. Please look at the compatibility list included in the AVR-CDC project or test a simplified prototype on breadboard with your computer if you want to use CDC mode.

We recommend that you use AVR-Doper in HID mode instead, which has no such problem. This mode is supported by avrdude. More information about interface modes and their relative advantages can be found in the project description.
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