DIY Servo Signal (PWM) to PPM Converter - Page 8 - RC Groups
Thread Tools
Jan 19, 2011, 05:47 PM
Registered User

fuse settings

Just another thought regarding fuse settings - please note that setting a fuse to (1) means it is UNPROGRAMMED ! setting it to (0) programs it.
Apologies if you already were aware of this - just trying to sort your problem out!
Last edited by helidave1; Jan 19, 2011 at 06:10 PM.
Sign up now
to remove ads between posts
Jan 19, 2011, 06:10 PM
Registered User
For the chip you are using, and as you have an external xtal, I think you only need to disable "divided internal clock by 8" (CKDIV8) and enable external oscillator (CKSEL3, CKSEL2, CKSEL1, CKSEL0 to 1100).

If this doesn't do it - buy the ATTiny 2313 and hey presto, all will be sorted!
Jan 19, 2011, 06:13 PM
Registered User
what is your programmer hardware based on?
USBHasp ?
Jan 19, 2011, 06:16 PM
Registered User
richardkalaf's Avatar
Originally Posted by helidave1
If the signal on the inputs is clean then the output signal should also be clean as the circuit is so basic I don't see where distortion can be generated (assuming you are testing the unit on its own and not connected to any other electronic gear).
I used PonyProg (free software) and a very, very simple parallel port program unit based on a few resistors and a 25 way D type connector. Works like a charm on a wide range of stuff and costs almost nothing to make. I think Sadsack showed a similar unit in an earlier post.
In addition the PonyProg software allows you to read the fuses/security bits and program them. I initially thought I had mis-read the order of the RX channels I wanted to use but in the end I noticed I had set the ckldiv8 bit and this was causing my problems. If the signal you are seeing on the output pin is a correct assimilation of the sum signal (all the channels are there and they all change when you waggle the relevant stick) then I think your problem is most likely the fuse settings.
Humm...ive downloaded PonyProg and im trying to use it but none of my computers have Parallel or Serial ports. Im using a USB AVRISP programmer.

Ohhh why does it have to be so dificult? lol
Jan 19, 2011, 06:30 PM
Registered User
if so...i found it easy to use command line Avrdude.

"D:\WinAVR-20100110\bin\avrdude.exe" -p 2313 -c AVRISP -C "D:\WinAVR-20100110\bin\avrdude.conf" -P usb -U flash:r:"C:\com-teensy\blinky-at90usb162.hex":i -U flash:v:"C:\com-teensy\blinky-at90usb162.hex":i -U lfuse:w:3A -U hfuse:w:EF -U efuse:w:F0 -F -q

in red is what Rich posted the blue don't change...but check my fuses setting.

opps you got usb
Jan 19, 2011, 06:33 PM
Registered User
richardkalaf's Avatar
Maybe this could help.

Heres a screenshot of my PROGISP screen.

Those are basically the options i have. Ive put a circle around the "Enable XTAL" option.

But maybe if you guys look carefully at the rest of the options you can see something wrong that im not seeing.

Im really sorry to bother you all with this. I hope i will be able to repay you with any knowledge in the near future.
Jan 19, 2011, 06:33 PM
Registered User
this is a fav that help me.

just put high low fuse setting but leave extended fuse alone
Jan 19, 2011, 06:38 PM
Registered User
i have used that one before. there should be a panel which show all the fuse options. Has lots of check box's. If you look under it you'll High Low Ext number put in the HF box EF LF box 3A. and you see chech boxs change.
Jan 19, 2011, 07:25 PM
Registered User
richardkalaf's Avatar
This is driving me nuts!

avr8-burn-o-mat only supports the newest chips.
Avrdude seems to not work with my programmer.

I finally found the fuse configuration in PROGISP. You have to click that "..." box nex to "AUTO" . Who would have guessed??

But it seems that it doesnt want to program the fuses! I input the values, click write, it says written ok, i click read, the fuses return to zero. Ive tried the process several times in different ways and nothing.

I cant buy a ATtiny because they are very hard to find where i live.

This is driving me crazy in frustration. Ill go eat something and have a smoke before i pick up my sledge hammer and stick the fuses in there my way!
Jan 19, 2011, 07:32 PM
Registered User
erase chip then program with default setting...think you just reselect you mcu again.
That nearly sent me mad trying to change bootloader on at90usb
Jan 20, 2011, 11:12 AM
Registered User
richardkalaf's Avatar
Im not so experienced with scopes either, so im not sure if what you see in the video is just a matter of adjusting something on the scope, or if its a real unwanted effect on the signal.

Notice how the signal keeps shifting to the sides, if we can call it that.

Maybe thats why i still cant get MultiWii software to recognize it?

Does anyone know why this happens and how to fix it?

PPM SUM Converter flickering? (0 min 11 sec)
Jan 21, 2011, 03:10 AM
Registered User

scope video

Its difficult to see what's really happening in the video but it appears that your signal is much cleaner than before. Regarding the signal moving off screen, that's probably down to how your scope time/div is set but there are many settings on a scope that you can adjust to capture the image you want and it's too complex to go into in any depth in a forum like this. Do not forget that the tx transmits blocks of data continually as a data stream so the scope will update with this information and depending how its set you may well see what you have noticed on screen.
What would be interesting to see is how each pulse width varies as you move the tx sticks. If this is clearly happening and your software still does not see your signal then you have either a software issue (not likely if others are using same software without problem) or the signal trigger edge is not good enough.
Does your software expect to see the sum signal in a certain order? i.e throttle followed by Ail, followed by rudder etc. If so, then you need to check that's what you are sending.
Last edited by helidave1; Jan 23, 2011 at 06:01 AM. Reason: spelling mistakes!
Jan 22, 2011, 12:46 PM
Registered User
richardkalaf's Avatar

Just to let you know, ive managed to stabilize the signal with 2 transistors, and now the software can recognize it.

The only problem now is that AUX1 seem to be not working. It doesnt detect any changes in the AUX1 switch, but on the scope i can see the pulse changing size correctly when i activate the switch.

Thanks for all the help so far, and if by any change anything comes to mind as of what the AUX1 problem might be, id love to hear about it.

Thats the only thing stopping me from soldering it all on a board and putting it onboard and start calibrating for flight!

Jan 23, 2011, 06:07 AM
Registered User


Is this down to the software you are using? If it was written for a 6 channel sum signal then it may well be seeing your AUX1 input but simply ignoring it because the program is not looking for it to change.
If the scope is now showing you 5 clean signals with good edge trigger and the software can detect the first 4 I would be looking at a software issue rather than hardware.
Anyway, that's all that comes to mind at the moment... good luck with it.
Jan 23, 2011, 06:20 AM
Registered User
would be nice if you post your change's, how you sorted it.
So others can benefit

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion how to convert PWM servo signal to DC voltage sahilkit DIY Electronics 15 Oct 05, 2008 10:23 PM
Mini-HowTo Motor PWM to PPM impulse converter quax DIY Electronics 27 Jun 17, 2008 12:38 AM
PWM to servo signal conversion? mcross DIY Electronics 13 Jul 05, 2005 09:48 PM
Futaba PCM receiver servo pulse other than PPM? risto Power Systems 14 Feb 14, 2002 01:18 PM