Positron BASIC Community

Hi,
I am sure I am not alone with this but I am trying to install Jon's bootloader to an 18F258 and get the error VPP voltage level error. This seems to happen a lot and I cannot find a reason for it. I have tried different leads, every permutation of the settings and power both the Pickit and the board and still no go.
Any advice would be welcome as this has always been a bug with my Pickits (I have 3) and all do the same.

regards,
Bob

I had some problems a long time ago with the simple reset/VPP pin using just a 10K pullup and 100nf capacitor alone.  The delay charging the capacitor appears to have been the problem so now I always include a series diode as shown in the PICkit user guide.

Bob, that's a bit of an old school part. What Vcc are you using, it might be happier on 5V?

John

Hi John,
I am on 5v, i was thinking doing the opposite.

Hi SeeMos,
It is John's board so I cannot really change it easily.

This is the main reason I want to use a bootloader as the pickit 2 is supposed to be the best one microchip offer and it is so buggy.

Bob

Never have problems with the PICkit2 and have it now for about 15 years.
Programmed a lot of PIC devices, from the simple 10F til the newest 18F series.
Not buggy at all 

Make sure you remove the bootloader jumper (LK2 I think)... the 258 uses a high voltage MCLR/VPP so it would cause issues with the CH340.

As mentioned the cap on MCLR can be an issue too.

Absolutely correct, always remove the B/L RST link when using HV programming.

The capacitor and resistors connected to the /MCLR pin conform to the datasheet recommendations so shouldn't be an issue.

John

Hi,

QuoteMake sure you remove the bootloader jumper (LK2 I think)... the 258 uses a high voltage MCLR/VPP so it would cause issues with the CH340.

That allowed me to program it but not sure if it has messed up the board. When I try to download via the bootloader it says reset the board and nothing happens even with the reset button.
Going to try with a known working device so I know it is not the untested 258 bootloader. I also have another board so I will swap that as well to find out if the board has had it.

A bit annoying as this is the first time I had that link in place.

I still maintain the PicKit 2 is buggy, I have 3 of them (EPE had an offer for £10 a very long time ago) and they all do the same thing with the VPP issue, they also dump the firmware regularly. Both issues are on the internet so not just me.

Regards,
Bob