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PostPosted: Thu Aug 09, 2007 8:12 am 
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Location: Sheffield, England
A couple of years ago I bought a K8048 kit for programming PICs. I built it and connected it to my PC. It wouldn't work at first - 'K8048 not found at Com1'. I fiddled endlessly with settings, but had not joy. Then - a few days after the original build - I tried it and it worked. It worked flawlessly thereafter. I built a PIC-based electronic ignition system for my XS250, a car alarm and various LED flashing devices. :D :D :D :D

Since originally having the K8048 and using it a lot, it eventually went into storage next to my favourite old Psion 3a. Between then and now, I've had more kids, a replacement PC, extensive root canal work, a couple of great big motorbikes and an ant problem. Recently, though, I wanted to get back into the PIC side of things and drafted a rough design for a binary clock - based on a PIC at its centre. I dug out my trusty K8048 and plugged everything in. Alas! 'K8048 not found at Com1'!

I put this failure down to a poor original build, so went and bought a new VM111 (the ready-made K8048) from Maplin. Let me just say that the soldering on the back was brilliant compared to my own efforts. It even came with a brand new serial cable! Last night I plugged it into the serial port on my PC, but unfortunately I got: 'K8048 not found at Com1'.

I am using Windows XP and the PC has a serial port built into it (the motherboard had been specifically selected to ensure this).


I have tried the following:

- Changing the serial port settings in Windows device manager (many times).
- Changing the BIOS settings (many times - from IRQ3 to IRQ4 to 'Auto')
- Changing the serial cable for some older ones I've got in a box of bits.
- Changing the settings in the programming software.
- Checked the power supply - it is 12Vdc unregulated.


Important: The power light comes on on the board. The included PIC can be run successfully (it lights the different lights on the testing part of the board).

When I put it into program mode, the little read/write light comes on and the 'Tardis-like' red flashing light begins its 'dance of joy'. If I then try to 'write' from the software the error message comes up on the screen, but the little light goes off. The little light comes back on when I 'OK' the error message. I guess this means that the serial port must be connected and that I must have selected the correct one?

I've read through the other posts at length. Some people have had this problem, but their solutions did not work for me. The problem is identical on both my K8048 (now lovingly restored) and on my brand new 'gleaming' VM111.

Any help or suggestions greatly appreciated. This is a great product and I got a lot of enjoyment and value out of it last time round. Every new electronics project I can now think of (and there are quite a few) is PIC-based - so I need this baby working!


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PostPosted: Thu Aug 09, 2007 8:54 am 
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Joined: Fri Dec 08, 2006 8:11 am
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Hello,

If this message is displayed on your screen: 'K8048 not found at Com1', there is realy a hardware problem. This message only appears if the test signal that is written to the K8048 isn't received again (loopback) via the input section.
So, maybe a failing cable,serial port, power supply (you need +/- 15V at the input of your K8048).
IRQ and bautrate settings doesn't matter because our PIC programmers doesn't use the RS232 protocol but emulated I2C via the handshaking lines.
Please test it on another PC configuration.

Most other problems are related to serial port compatibility, USB routed serial ports or limitations of the programmer - PIC combination sush internal oscillator and MCLR used as I/O pin doesn't work.


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PostPosted: Thu Aug 09, 2007 9:01 am 
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Thanks for your rapid reply. Your help and suggestions are greatly appreciated! I'll try each of your suggestions in turn on both programmers and post the result on this board.


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PostPosted: Thu Aug 09, 2007 8:37 pm 
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Since this morning's post I have tried the VM111 with the following:

- A different PC, running Windows 98. Same problem.
- 2 different serial cables to the one included. Same problem.
- 2 serial cables joined together. Same problem.
- Every single different speed setting for the serial port.
- Every single different speed setting for the ProgPic program.
- Every different setting possible for the serial port.
- A different power supply to the one normally used (recommended by Maplin).

I've tried removing and replacing the chip. I've checked the voltage from the unregulated supply (15.5 volts DC on the multimeter).

I've tried all the above with the switch on the programmer in prog mode, run mode and in the middle setting.

I've checked voltages from the different pins on the serial port on my main PC. I'm getting 12volts at idle between ground and pins 3, 4 and 7. This is the same as when I plug the cable into the PC and check the end of it.

Frankly I am completely stumped as to what's causing the problem. This was a pre-built kit, so it isn't down to soldering or any build mistake on my part. I've spent over 5 hours on this problem. I don't see what more I can do, so will take it back to the shop tomorrow for more help.

Thanks for trying to help, but this one seems to be an impossible fix.


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PostPosted: Sun Aug 12, 2007 7:48 pm 
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For completeness I am reporting what happened after I took the pre-built board back to the shop (VM111). They gave me a refund, leaving me with my older K8048.

I then went to see a friend who is an electronics engineer and he said that many modern motherboards do not have a 'true' serial port. Many now are in fact 'emulated' serial ports (this applies to some desktop PCs as well as laptops). Bizarrely, this means many modern PC's (although appearing to have serial ports) will not connect to some serial devices (such as the K8048). He said that I could have spent as long as I'd liked fiddling with the settings but that it would never work.

The solution was to get an old Pentium 2 out of the loft and install Windows 98 on it. I put the software on, connected my old K8048 to it and it worked!!! So, a happy ending!!!

Like most Velleman products I've bought in the past - the K8048 is a great little tool at a good price - and not hard to build. However, I would advise Velleman to develop it into a USB-based device - due to the increasing serial port issue on newer PCs. Thanks for reading!


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