USB to Serial problems

[spondootre]

I've been using a velleman PIC programmer board connected to my desktop without any problems (apart from I now have about 10 chips it refuses to do anything with but that's another issue) I need to adjust the timings of a program I have written while at another location. They have a desktop the same as mine I can use but I thought I would use my laptop to blow the new program to the chip. It doesn't have a 9 pin serial port on it so I bought one of https://www.maplin.co.uk/Module.aspx?ModuleNo=29968&criteria=serial%20adaptor&doy=27m11. there were no problems installing this, laptop rebooted, connected the velleman board to it, changed the serial port on picprog2 to COM3 as this is what the USB adaptor registered itself as. The velleman board was detected. The program will erase the chip with no problems, but if I try to blow a program into it, it just says "erasing" then "writing" but never moves on and just errors out after a while. Has anyone got any suggestions?

Also are there any decent USB programmers I should look at buying? Perhaps a decent one will bring back the growing pile of unusable PICs !!

 

[Nigel Goodwin]

You generally can't use a USB/serial adaptor, because these crude 'serial port' programmers don't actually use the serial port, they just manually 'wiggle' some of the handshake lines on the port.

You might look at the Inchworm ICD2 clone on these forums, it's a proper serial port programmer and will work fine with your USB adaptor.

 

[spondootre]

Thanks Nigel,

If I buy an Inchworm kit from blueroom, do I also need to buy a seperate for the PIC to be programmed? I can't seem to find them on the site? Is this the best place to be buying from or should I look at other ICD2 clones?

 

[Nigel Goodwin]

The advantage of the Inchworm is the author is on these forums, but essentially it's the same as other ICD2 clones - but uses a VERY nice quality PCB. If you want to program PIC's out of circuit, you just need a little board with a socket on and connect it to the Inchworm.

 

[spondootre]

So if I buy the Inchworm I wouldn't need the firefly aswell, I could essentially just use a normal IC socket on a board, or a few different sized sockets for different PICs. That makes it much better value!!

 

[Nigel Goodwin]

So if I buy the Inchworm I wouldn't need the firefly aswell, I could essentially just use a normal IC socket on a board, or a few different sized sockets for different PICs. That makes it much better value!!

Yes, you don't need the FireFly - either stick a socket on a bit of board, or add an ICSP socket to your project board.

 

[William At MyBlueRoom]

So if I buy the Inchworm I wouldn't need the firefly aswell, I could essentially just use a normal IC socket on a board, or a few different sized sockets for different PICs. That makes it much better value!!

Inchworm designer here

You don't need a Firefly unless you need either a tutor or a ZIF socket adapter.

The ZIF is really easy to hand wire, but a PCB looks nicer and will hold up to handling better.

If you had the forward thinking to leave the ICSP pins open in your design it's just a matter of connecting the clock, data & reset lines.

If you build the Inchworm (hand wired yourself lots of folks on a budget do this) you'll still need to load a bootloader into the 16F877(A).

On Nigels WinPicProg page (a must read for anyone learning PICs) includes a tried and true PIC programmer and software (WinPicProg) combo (which CAN program the 16F877 bootloader for the Inchworm ).

For the beginner it's worth it to build a simple programmer; or if you want to dive right in build the Inchworm and you get a MPLAB ICD2 compatible programmer and debugger. (I don't sell it directly but check the "where to buy" link)

PS a SUPER SIMPLE LVP (not recommended but you can program the bootloader with this then use it to program another 16F877 in HVP mode for the inchworm, you'll have to hold RB3 low to use the LVP chip)

**broken link removed** I based the Inchworm on his design.

**broken link removed**

 

[spondootre]

Thanks William

If you build the Inchworm (hand wired yourself lots of folks on a budget do this) you'll still need to load a bootloader into the 16F877(A).

But if I buy the kit from your website the bootloader will be programmed onto the PIC? So I would only need to add a simple circuit (as on page 6 of the assembly instructions) to the board to connect my usual 16f818 pics to it?

Do you sell the inchworm already assembled or only as a kit? Can I buy it straight from you or should I use one of the links on your site??

questions questions questions!! sorry!

 

[spondootre]

Also how long is delivery to the UK?!! (Yet another question)!!

Thanks

 

[William At MyBlueRoom]

Contact www.dipmicro.com I'm setting up distribution in the UK, trying to get the attention of a good UK kit seller.

The Inchworm comes with a preprogrammed 16F877A

Yep just wire up the target as in the instructions, use the Firefly schematic to see how it's done on most 18pin PICs.

 

[spondootre]

Thanks, i'll get one of these ordered in the next few days.......I'll be glad to get rid of this velleman board (which was more expensive than the inchworm) and perhaps resurect my pile of redundant PICs.

Cheers

 

[tunedwolf]

I suspect your pile of non working chips, actually only need properly erased, I have seen this happen a bunch of times with dodgy serial port programmers...
They program around 75% of the devices you try, then boom, two don't for some mysterious reason, and what's worse you can't erase them either, so can't retry, I used to see some poor folks really frustrated by it in the early days...

 

[Nigel Goodwin]

I suspect your pile of non working chips, actually only need properly erased, I have seen this happen a bunch of times with dodgy serial port programmers...
They program around 75% of the devices you try, then boom, two don't for some mysterious reason, and what's worse you can't erase them either, so can't retry, I used to see some poor folks really frustrated by it in the early days...

It's usually because you set the internal oscillator, this prevents you erasing them in poorly designed programmers.