Objective Development Forums

My first guess would be that you have not programmed the fuse bits correctly and the AVR is running on the internal RC oscillator. As Grendel already pointed out, an unknown or malfunctioning device usually indicates that the AVR is not sending any useful data at all.

Since it's not necessary to have four ground pins, I usually connect two of them to RxD and TxD for debugging purposes. AVR-Doper can even read the debug info from these pins. If you use AVR-Doper for In System Programming, you can print debug info through the ISP cable and AVR-Doper. The additional...

Anonymous wrote:Does anybody have any experience with a AT90S2313-10PC (10MHz)... is it possible to use a 12 MHz quartz?

I have tried a couple of them and none failed, even at 3.5 V....

1. I compiled the code in winAVR instead of avr-gcc in linux without setting the alignment or using ATmega161 compatibility mode and it worked fine, how is that possible? This is probably a slightly different version of gcc. I have not found a rule how memory addresses are assigned to variables. Lo...

Two questions: (1) Do you limit the D+ and D- voltage with zener diodes? Some host controllers don't work with levels considerably above 3.3 V. [Even if you don't use those zeners, your host seems to tolerate the 5 V.] (2) Do you run the command line utility as root? Linux has Unix permissions for v...

No, that circuit is not correct. Not only the voltage for the pull-up resistor needs to be limited, it's also the signal voltage.

Please download the Automator or AVR-Doper project and look at the circuit diagram. Both project use the Zener Diode approach.

You must make sure that your interrupt service routines can be interrupted by the USB interrupt. Timing is VERY critical for AVR-USB, the interrupt handler must be called with only a couple of cycles latency.

OK, thanks for the valuable input! I have found a bug in the ISP code when doing "value polling". This mode is used for older devices such as the AT90S8515. We will release a new version soon which fixes this firmware bug. [This still does not explain why connecting through a hub makes a d...

Sorry, but I'm out of ideas. At least you've found a configuration which works. There's one more thing you can try: If you use the "-v" option to avrdude multiple times, you get more verbose output. Please use "-v -v -v" to see all the communication detals. Please send that to me...

This is indeed very interesting and I have no obvious explanation for it. One possible explanation: Bulk endpoints need lots of CPU time on the AVR. The timing with your host may be so that there is no (or almost no) time left for programming the AVR. Thus the timeout. When you insert a hub, timing ...

OK. 5 usec is fast enough to avoid any timeouts. Another possible cause for timeouts is that the supply voltage for the target is too low. There is a tighter limit for programming than for other operations. If the internal programming voltage does not reach its minimum, programming won't work and we...

We have removed this requirement in one of the latest releases. You can now use any bits of the port for D+ and D-.

If you happen to use an old verison of AVR-USB, you will get a compiler error when D- is bit 4.

Have you tried to measure while you read the entire flash? You should see at least one second of activity. It may be hard to read off the frequency during that time, but we don't need exact figures anyway. A storage scope would, of course, be helpful.

The ISP clock is pin 6 of the 74HC126 or pin 25 of the ATMega8. It will only toggle when the AVR is programmed or read.

You can get usage information for avrdude with "avrdude -h". Which jumper is the ISP jumper? You already reported that it worked in HID mode (at least reading). What's different now? Please ensure that JP2 (Slow SCK) is open. If you have a scope, please also check that the ISP clock is rea...