Really interesting! So, there is a relationship between my problem and the length/number of wires. I have a fixed length of all my wires: about 8cm (this value corresponds to half of my breadboard width). The advantage of this length is that I can reach components that are far and components that are near (so it is more reusable).
That is a big constraint to work at 12 Mhz if it requires to have a limited length/number of wires. I will try to reduce the number of wires and if it does not work, I will not have the choice: I will create shorter wires (specific for this circuit, so less reusable). I have just successfully done a circuit using a lot of useless wires here: http://yugiohjcj.free.fr/elec-vusb-led-1.jpg http://yugiohjcj.free.fr/elec-vusb-led-2.jpg It is an USB connected breadboard that is controlled by a program on the computer [1, 2]. I can switch on or switch off the LED. In this case, I have no problem... Do you know why I have problems with the USBasp project and not with this one? [1] https://www.youtube.com/watch?v=iA15vqa0Rk8 [2] http://www.wzona.info/2012/10/usb-duomenu-perdavimas-atmega.html > Hi, > The real problem is capacitance on USB wires. Long story short: the USB > cables should be short as possible since USB working at 12 MHz (at least > USBasp). > Also 12 MHz crystal should be very close to AVR chip. Long wires make > troubles :) > Regards > Martin > > > > This is a photo of my breadboard: > > > http://yugiohjcj.free.fr/usbasp.jpg > > It looks as if you have "too many wires". This schematic should have > just the CPU, a couple of wires to USB and a few (4) wires going to > the target. Together with two zeners and a two resistors, I expect > about 12 wires in total. I'm seeing about 3 times too many. > > Roger. > _______________________________________________ AVR-chat mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/avr-chat
