Problem proramming PIC 16F886 with PICKIT2?

[Jerson]

Jellis00

You can point explorer to the hex file in ProgramFiles\Microchip\Pickkit2 v2 or similar. That is what it is looking for.

as for the yellow box telling you no device found, it is very likely you are connecting the pickit2 to an unpowered board which may be loading the pickit2 resulting in this message. You may also get the ding-dong of USB device disconnection. If this is happening, I advise you should try to program an isolated PIC. No other components on the board. Another way is to power up your board and then try programming with the pickit2. It automatically senses that the board is powered and makes adjustments to its power conditions.

Hope that helps

[Dick Ivers]

Hello again, Another thing to look for: Double check that the power light on the Pickit2 is on. After repeated usage the mini USB connector can break away from the board inside the Pickit2, and it loses power. This happened 3 times with mine ... I repaired it each time.

[jellis00]

Jellis00

You can point explorer to the hex file in ProgramFiles\Microchip\Pickkit2 v2 or similar. That is what it is looking for.

One thing I have considered is that my OS may be contaminated. I want to download the latest OS version for the PICKIt2 and install it to see if that solves the problem. But as I said above, I can't find the latest OS on the web that I can download. Can anyone point me to one?

My PICKIT2 is showing a power light so I don't think that is a problem. However, I will (at Jerson's suggestion) try to isolate any power issues on my application board. Thanks for the ideas.

[BH_epuk]

I have had strange programming issues with the 16F88x series and Pickit2 a while back.
Turned out to be the PGM pin (RB3) on the PIC needs to be pulled down to GND with ~10K - page 228 of the datasheet.

Hope this helps

[jellis00]

I have had strange programming issues with the 16F88x series and Pickit2 a while back.
Turned out to be the PGM pin (RB3) on the PIC needs to be pulled down to GND with ~10K - page 228 of the datasheet.

Hope this helps

BH_epuk: I went to pg 228 in the 16F88x data sheet and the only thing I find that equates to what you are saying is:
"

4:

RB3 should not be allowed to float if LVPis enabled. An external pull-down deviceshould be used to default the device tonormal operating mode. If RB3 floatshigh, the PIC16F882/883/884/886/887

device will enter Programming mode."

From this quote it appears that what you are saying only applies "if LVP is enabled". I am not enabling LVP so I don't think this applies in my case. In fact, I have RB3 connected to Vcc via a pullup resistor of 10K ohms. Your opinion?

[BH_epuk]

Give it a go with PGM pulled down. I only found this after intermittent programming problems on a project some time ago, now allways keep this pin in a way it can be pulled down (even if it means an extra pad on the PCB).

If the device is new then LVP is enabled - note 5 on P228, but i also suspect if the device is erased is default's back to this.

Edit:

In your case pullde to VCC via 10K, just shorting RB3 to GND while programming would do the trick.

[jellis00]

Finally found the problem. Evidently the 16F886 chip had gone bad. When I replaced it with a new chip everything works fine. Don't understand what caused the chip to fail.
In my next board version, however, I will implement some of your suggestions as far as the PGM pin is concerned.

Thanks for all of your good ideas.
John Ellis