Noob to ICD2 clone...

I just received my ICD2 clone through the mail. For reference, it's this one:
https://www.mcumall.com/comersus/store/comersus_viewItem.asp?idProduct=3195

I've been reading through the documentation that came with it, and I was a little surprised to find out that the target would need its own power if I was powering the ICD2 via USB alone. This is according to the Microchip MPLAB ICD2 info, by the way, so I'm not 100% that this applies to the ICD2 I have. There's no independent power connector on my ICD2, so USB power seems the only option. I think I should mention that my ICD2 has a set of three jumper-pin pairs on it, and these are marked:

5v0-tar
3v3-tar
tar-self

and it came with the jumper on 5v0-tar, so I'm thinking my ICD2 is perhaps built to provide power to both the ICD2 and the target from USB. Am I being too naive here, or do I have that right? Sorry, a lot of this is new to me but I figured I'd throw myself at it for some summer fun!

I've read the discussion here:
https://www.electro-tech-online.com/threads/cant-porgram-my-16f54.19437/

where Jay comments:

Jay.slovak said:

Do not connect the ICD2 9V power cable if you use USB!
USB has enaugh power for both ICD2 and it's target. Read ICD2 manual!

Click to expand...

and Jay seems quite convinced of this, even though it's in direct contradiction of what Microchip's poster on MPLAB ICD2 says. Microchip says if you're powering the ICD2 by USB alone, you won't have enough power to run the target off the ICD2 (so the target will need its own supply). Unfortunately, the supporting documents for my ICD2 are somewhat lacking (I guess you get what you pay for!). Having browsed the web a bit, I'm starting to gather that not all ICD2s are created equal? Is it possible the jumper on my ICD2 I mentioned previously is for choosing target power source options (either 5V powered by the ICD2/USB, 3.3V powered by the ICD2/USB, or self-powered from other than the ICD2/USB). My instincts tell me I'm right, but I wouldn't mind someone else's opinion on this in particular and the wide world of ICD2 options in general.

When just powered from the USB you can only draw 100ma before the port shuts down. It is possible for a USB device to request more current (up to 500ma) but the ICD2 and its clone don't.

So with only 100ma and the ICD2 taking anywhere between 20ma - 60ma for itself that's very little current for the target. The real ICD2 has an external power adapter as does my Inchworm design, the Inchworm can supply almost 1 Amp of power to the target.

When just powered from the USB you can only draw 100ma before the port shuts down. It is possible for a USB device to request more current (up to 500ma) but the ICD2 and its clone don't.

Click to expand...

D'oh! That's what I get for cutting corners, I guess. Ah well, in for a penny, in for a pound. But then why would there be a jumper set called "tar-self" as an option if it wasn't being powered by the USB for the other two options? Is there any harm in trying to see if it all works from the USB?

Failing that, what's the deal with powering the target PIC independently of the ICD2? The carrier board with the ZIF socket comes with two RJ12 sockets (one for 8-18 pin PICS, the other for 28-40 pin PICs), and a 5-pin header with each pin labelled VPP, GND, VDD, RB7, and RB6. I gather VDD would go to the + of my external power, and GND to the -, but what of the others? And why (if they do) do those need to be connected to anything since they'd (I would have thought) been getting that from the ICD2, even when using external power anyway?

The buyer's remorse is setting in. Still (and perhaps obviously), any help would be swell. Thanks.

It looks like a nice programmer, very few USB enabled clones have a seperate power supply. Besides they're easy to build.

The ZIF socket target are meant for out of circuit programming and there is enough power via USB to run those just fine.

Small projects will run fine from USB power, I've even managed a 65ma LCD with backlight but the USB on my laptop (Fujitsu) can get annoyed. Won't hurt it, just have to unplug for 60secs to allow the USB self resetting fuse to reset.

If the target (your project) has power then simply connect VPP, GND, PGC & PGD (ususally RB6 & 7)

I'm not sure what tar-self means, do you have a link to a manual?

The ZIF socket target are meant for out of circuit programming and there is enough power via USB to run those just fine.

Click to expand...

That's good news, since I think my plan is to just program out of circuit for the first bit anyway, but it brings another question up that's been in the back of my mind. How does one go about in-circuit programming? I mean, what does that look like? Can anyone direct me to any photos of projects where that's happening? I just can't imagine a situation where that would be practical (that is, more practical than just taking the PIC out of the project circuit to re-program it), but perhaps that's just the limits of my imagination. Is it just a matter of connecting leads to the appropriate pins of the PIC in circuit, and then those to a 5-pin molex on the (in my ICD2's case) non-ICD2 header (or perhaps I should say "ICD2-out" header?)? Sorry if that's obvious to the experienced members, it's just not that apparent to the uninitiated! If VPP is the target power, what's VDD again...?

I'm not sure what tar-self means, do you have a link to a manual?

Click to expand...

Ah... no. All I got with the ICD2 was a CD with some help files from the Microchip site (which I had already), some confusing instructions about installing a USB driver that also explain that I don't need to install a USB driver (?!), illustrations on putting different size PICs in the ZIF properly, and a short (incomplete) note explaining the sequence of events to get the ICD2 running (i.e. what to turn on, load up first) with no mention of target power options. Sorry I can't be more helpful, I could post my own photos of it if you like. I was thinking self-tar needs to be selected if the target is providing its own power, and 5V if it needs that instead, or 3.3V if it needs that instead.

I should have mentioned that I contacted the distributor's support e-mail with my concerns (about target powering). I got a prompt reply... stating that I will soon get an answer. We'll see!

The support from the distributor got back to me. This is what they wrote:

The USB port is able to provide up to 500mA current. The ICD2 itself need
about 100mA.

If your target board needs more than 300mA, then you need an external power.

However, if you only use the ICD2 as the programmer, then the ICD2's adapter
does not need external power. And all chips should be working.

For the ICD2 marked "5v0-tar," "3v3-tar," and "self-tar".

"5v0-tar" is for those 5V devices
"3v3-tar" is for those 3.3V devices
"self-tar"will disconnect the power from the ICD2 to the target.

Click to expand...

That explanation seems to indicate you have one of the "better" designs in that it supports programming 3.3v target devices. Not many do. All in all I'd say you've done well and deserve an "at-a-boy" (grin).

Case 'n all, that's really a nice lookin' USB-ICD2 clone... Where did it come from (shipped from where)?