Out of the ICD circuit PIC?

[Hedos]

Hi,
I wanted to try a PIC outside of its ICD circuit (connected to the Inchworm) after programming it. I programmed it with the Flash a LED code from William for the 16F628A.

The program works perfectly in the ICD circuit. If I remove the PIC and put it in another circuit, powering it from a regulated 5V supply, it doesn't work. I have a constant ~2V on RB0 where I should normally see it switch from 5V to 0V every ~1.2 seconds according to the code.

Do I have to connect more than just Vss and Vdd to have a functional PIC?
If so, where could I find this information by myself? The Microchip datasheet for the 16F628A is not very helpful for getting started, it is too dense with advanced technical information.

One more thing: When I try to use the Inchworm as a programmer only, there is no problem. If I try to use it as a debugger, though, I get this error when connecting from MPLAB to the Inchworm: " Invalid target device id (expected=0x89, read=0x83)". I use a 16F628A and when I go to Configure -> Select device, there's a green circle beside MPLAB ICD2 Debugger, so it should be supported.
Do the connections to the target PIC have to be different for debugging from just programming?

 

[Nigel Goodwin]

You need to connect the reset pin (MCLR) to 5V as well, or set it to be done internally (but this causes problems with the ICD2 programmer).

 

[Hedos]

That works, thanks.

 

[William At MyBlueRoom]

Use a resistor 10K or more between MCLR & power, bad practice to tie directly to power.

 

[Nigel Goodwin]

Well it's not bad practice- it's necessary or else the ICD2 can never reset the PIC (or manually either).

True, it's not bad practice UNLESS you want to reset externally - obviously you have to be able to do this when using an ICD2. Adding a pullup resistor gives no advantage other than that, if you don't need an external reset, then connect it directly - the PIC is designed to be used like that.

 

[dknguyen]

I deleted my post as you replied because I realized what was going on (it wasn't running in the ICD circuit).