a. My K8055N board does not connect to a PC. What can I do?

QUESTION:

I also have the Velleman K8055N board, but I have a problem.

My computer doesn't detect the board...I have Windows 7 Professional 64bit.

This is the second time I have this board. The first one also didn't work. So I 've sent it back and got another one.

But with this board it is still the same...the computer doesn't detect it :-(.

I checked the soldering and it is OK.

Now I don't know what to do...do you have any idea?

Is there a way to manually install any USB drivers?

By the way...I also connected the board to an older computer with Windows XP Professional 32bit...still the same...doesn't work.

If you have any idea, please tell me.

ANSWER:

I have 2 original Velleman boards K8055N that came with PIC18F24J50 microcontrollers. I've never experienced any problems with connecting them to any version of Windows, starting from Windows XP. I tested them on 32-bit Windows versions and 64-bit Windows versions (Windows 7 as well as Winows 8), as well as server versions (Windows Server 2008 and Windows Server 2012).

All Velleman K8055(N) boards come with programmed PIC microcontrollers that connect to a PC as HID devices and they use the original HID driver that is inbuilt in Windows OS. I have also written my own FW for PIC18F24J50 and PIC18F26J50. There have never been any problems with the final versions of HEX files that I've published on my website and programmed with my PIC18 programmer that has also been published.

Therefore, I suspect that something might be wrong with your HW:

- Use ohmmeter to check connections from the chip D+ and D- pins to the end of USB cable.

- The original Velleman chip might be faulty. If you have PIC18FxxJ50 programmer (you can also build one), you might also buy a new (empty) PIC18F26J50 or PIC18F24J50 and program it with a suitable HEX file from my website. It should connect regardless of DLL and application support. You can check the connection status in Device Manager under HID devices list.

- Check the 4 MHz crystal and 27 pF capacitors and power lines soldering. If you use the original K8055N board the Q8 LED should blink a few times as the board is connected. If you use my programming the only possible check is to open Device Manager HID device list. I have omitted the Q8 LED blinking, because it makes the channel useless for serious applications. Suppose that you want to connect a relay that controls a house appliance or lighting and the relay goes quickly on an off a few times as you connect the board to an USB port...

- Check the power supply voltage on LM317T voltage regulator pin 2 (the middle pin). It should be exactly 3.3 V. Also check the voltage on PIC18F2xJ50 power supply pin (20) and USB pin (14).

- Check if MCLR pin (1) is connected to the power suppy through 4.7 kOhms resistor.

- Use an ohmmerter to check if Vss is conneted to PIC18F2xJ50 pins 8 and 19.

However, since the PIC18F2xJ50 programming is HID compatible, there is no need to install any additional drivers. But don't expect the green icon to appear on the taskbar as the PIC18 is connected. You have to take a look into Device Manager HID device list.

Click on the picture to enlarge.