Gyro GA250 + alternative Firmware: The Best of the Cheap!? - Page 3 - RC Groups
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Mar 11, 2012, 11:08 AM
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cgriffith's Avatar
I would like to get this thread refocused on OlliW's work with a question. I know very little of the specs of chips, how to program them, etc. My hang up on this mod, I have a AVR Programmer, but do not want to spend any money on the Arduino JY-MCU USB adapter. I saw plans to build one, but that is serial based and would still need some USB/Serial adapter.

Is there a way to use the same ISP AVR Programmer to flash the firmware AND program the settings?
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Mar 11, 2012, 01:06 PM
The parameter values are stored in the uC's EEPROM which you can access by the ISP programmer. Read the EEPROM, change the entries appropriately, write the EEPROM. The mapping of the parameters to the EEPROM you can infer from the .dev file. So, yes, it's possible. In principle. You just have to work it out.
Mar 13, 2012, 06:34 PM


Hey Folks,
the most "difficult" step in this project is certainly burning the fuses and the bootloader, which needs using the ISP AVR programmer and a (more or less) suitable porgram to run the latter. In order to make this step as simple as possible I wrote a little Windows PC program, which I called AvrBurnTool. With it you still have to open the GA250 case and solder cables to the ISP pads and connect these to your ISP AVR programmer like USBasp, but the process of burning the fuses and the bootloader hopefully is much simplified by AvrBurnTool. Get an impression by the attached figure.
Have fun, Olli

Mar 16, 2012, 10:39 PM
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Hi OlliW,
what an impressive project! Thanks for sharing.
Do you plan to make AvrBurnTool available for download?

Mar 17, 2012, 03:24 AM
oh, yes, of course... (thanks for mentioning)
Mar 19, 2012, 11:22 AM
Registered User
I can't seem to register at worldpress,

I'm also have problems getting the bootloader to talk but I'm trying to use a bluetooth rs232 converter. I have an ftdi on odrer.
Last edited by beer-man; Mar 20, 2012 at 01:47 PM.
Mar 21, 2012, 05:56 AM
Registered User
Amazing job! Thanks for all this!

Last night I burnt the BootLoader. Tonight I'll upload the firmware and start playing with the values.

Very exciting!

I'm setting it up on an hk250gt...

FYI I can't hard 3D but I can fly flips and rolls and backward circles. I hope I'll be able to contribute a little bit to this awesome project!
Mar 21, 2012, 06:11 AM
I can fly ... backward circles
cool... flips and rolls the gyro does provably handle... but for backwards a convincing prove is lacking
(I did some long tail slides but I can't do them well, need more practicing)(I just started going into practicing backwards, the last year I mainly practiced inverted)(which I still can't do that well ).
Mar 21, 2012, 09:48 AM
Registered User
How do you download v1.6, I can't register at worldpress I've tried 4 different emails and it doesn't like any of them.

also when I flash the bootloader I get no lights when I power it on. I'm using ponyprog to flash it with and have set the fuse bits using a fuse bit calculator. I can flash cruzado's and it powers up okay.

Any idea on what I'm doing wrong?
Mar 21, 2012, 10:20 AM
Registered User
Hi Olli,
could you please explain what is the difference between "classic" and "normal" mode of your firmware 16 gyro settings?
Is there possibility to use "fixed wings" mode for RATE and "normal" for HH mode?
How to use ProgrammBox? Connect it to gyro and power on gyro with connected ProgBox in same time?
I have plown Mini Funtana with FW16 in RATE mode and i looks pretty good (turns were solid). It has better feeling than in HH mode.
Today I plan to add roll axis gyro FW16 and it would make the plane even more stable. Will tell you ASAP.
Im going to order parts for making programming box to program parameters on field (now I have to program it at home). But Im not sure how and when it connect to bootloader.
Mar 21, 2012, 11:21 AM
as regards your registering problem, I sent you a PM

with only the bootloader programmed into the GA250 no leds will flash. (cruzado uses a different bootloader, don't know if it gives led signals, but if it does, it just means that it is a different bootloader ). You have to also flash the firmware using AVRootloader, see HolgiB's manual.

"normal" is the controller structure I used all the time in this project. "classic" is supposed to mimic the behavior of the commercial gyros, as you once asked me for. "fixed wing" uses the "classic" controller structure but additionally has the feature that if the transmitter gain is close to 50% that the gyro function is switched off.


the communication of the GA250 with the programming box can be established in two ways:
(1) The programming box is connected to the servo port before power up. After powering up the connection will be established and you can sett your parameters as long as you want. As soon as you unplug the programming box the gyro continues with its initialization process as it would otherwise do, and will eventually enter normal operation mode.
(2) Once the system had been powered up, the communication with the programming box can be enabled by again pluging the programming box into the servo port and then holding the rudder stick to the left. After about 10 secs the connection will be established, and you can set your parameters as long as you want. As soon as you unplug the programming box the gyro will jump to the initialization process, which will be passed fast however, and reenter normal operation mode. The rudder-left method is convenient since you don't have to power down your heli, which in most cases mean that the head speed won't be different after the programming (if you use a governor).

Please keep in mind: The changes to the parameters via the programming box will be effective immediately. However, they will not be stored permanently, that is, the changes will be lost by switching off the power. If you want the changes to be stored permanently you have to explicitly invoke the "Store" menu option! This is done by switching to yes by pressing the "+" key, and then to hold down the "+" key for at least ca. 1.5 sec until you see the programming box telling you that store is done.

The communication between the GA250 and the programming box is not via the bootloader as it is with the PC program AvrConfig), it uses a home-brewed communication protocol via a half-duplex serial.

EDIT: forgot, thanks for sharing your experience in a fixed wing apllication
Last edited by OlliW; Mar 21, 2012 at 11:39 AM.
Mar 21, 2012, 04:00 PM
Registered User
Thanks Olli for explanation. Now its clear.
Only one thing, if the programming box is not connected and I hold rudder stick long time (about 10s) gyro wont switch to programming mode? Flat plane slow turns could last quite long time holding rudder stick.
Mar 21, 2012, 04:32 PM
good question
actually two conditions must be met in order to enter the programming box mode
1) rudder must continously be hold maximally left for 10 sec
2) the gyro sensor signal must continously be zero for 10 sec
so, only if the plane turns extremly slow for more than 10 secs even with the rudd stick maximally left the programming box mode will be entered
if this can happen, then sorry man, you will crash
Mar 21, 2012, 07:03 PM
Registered User
More problems....

I've been following the idiot's guide but I'm probably too idiot

I've got my FT232 plugged as described but the AVRootloader can't connect. It keeps sending ident but never manages to connect. Any help is appreciated.

This is the output:

21.03.12-23:02:41-700 > Connecting on port COM3...
21.03.12-23:02:41-704 > Timeout.Connect = 50 ms
21.03.12-23:02:41-704 > Timeout.Base = 50 ms
21.03.12-23:02:41-704 > Timeout.Erase = 10 ms
21.03.12-23:02:41-705 > Timeout.Flash = 15 ms
21.03.12-23:02:41-705 > Timeout.Eeprom = 10 ms
21.03.12-23:02:41-705 > Timeout.Buffer = 1 ms
21.03.12-23:02:41-706 > Timeout.AppCmd = 0 ms
21.03.12-23:02:41-706 > Timeout.KeepAlive = 250 ms
21.03.12-23:02:41-706 > Timeout.RTSPulse = 0
21.03.12-23:02:41-706 > Timeout.RTSInterval = 0
21.03.12-23:02:41-707 > Timeout.ConnectTrials = -1
21.03.12-23:02:41-707 > Timeout.MaxPacketSize = 0
21.03.12-23:02:41-707 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:41-905 > received data $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52 3E 1E
21.03.12-23:02:41-905 > Switch to 1-Wire mode
21.03.12-23:02:41-906 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:42-133 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:42-350 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:42-582 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:42-805 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:43-029 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:43-253 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:43-476 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:43-700 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
21.03.12-23:02:43-924 > send ident $00 00 00 00 00 00 00 00 00 0D 42 4F 4F 54 4C 4F 41 44 45 52
Mar 21, 2012, 07:20 PM
Registered User
Ignore my previous post. I've re-flashed the bootloader, and then it managed to connect and upload the firmware.

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