K8055 not recognized by demo programme and led 8 stays lit

Kits PC Related Projects
1

Hi

I’ve just assembled the K8055 USB Experiment Interface board.
When i connect it to the USB the powerled turns on and led nr 8 flashes a few times but stays on. USB 1.1 does recognize something by saying that it may perform faster if connected to USB 2.0 (usual XP message).

Now, I’ve browsed this forum and this topic got my attention:

[quote]-Please check the voltage at pin 14 of IC3. Should be about 3V.
[/quote]
This voltage is 3V

[quote]- Check that C6 and R35 are right value and soldering OK.
[/quote]
This may be the problem, but i’m not sure. The capacitor described in the assembly manual (C6: 220nF/50v~ rectangular shaped) was not in the package. Instead a ceramics capacitor (model and color like C1) with the numbers 224 inscribed (=220nF?) was extra. So i figured that this was ok too. I’m not sure though…

Yes those are fine.

[quote]- Check that no short circuit between the signals D+ and D- and no short circuit from the signals to +5V or to GND at the USB connector.
[/quote]
Fine too

[quote]- Check or change the USB cable.
[/quote]
USB cable is fine.

Every soldering and component look fine too.

Is this capacitor C6 the problem or should i worry about something else?

Thanks
Geert

2

The capacitor C6 seems to be OK (220nF).
There is some other reason to the problem.

One reason may be a conflict with other USB devices connected to this PC.
Please see this thread for one solution:
[forum.vellemanprojects.eu/t/k8055-works-only-with-old-software-on-some-computers/1377/1)

3

The solution(s) you refer to do not work.
i’ve tested it with a pre-fabricated board, that 1 works ok. I changed the IC’s to see if those were defect and the prefab worked fine.
The prefab board appears in the device list the defect one doesnt.

A bit more specific, the voltage on pin 14 is 3,23 Volt.