HVP and LVP programming in PIC Microcontrollers

[embeddedlover]

I am working on PIC microcontrollers. They have this LVP and HVP programming options.

For LVP, it seems the PGM pin must be pulled high and for HVP, PGM must be pulled LOW. Another criteria is MCLR must be pulled high for HVP.

It seems by default the PIC will be in LVP mode.

Actually, i have a doubt,

I have pulled PGM LOW and MCLR HIGH in my cirucit which indicates HVP mode. Let us assume that i want to program a PIC for the first time, in this case by default my PIC is LVP mode and my external hardware settings are for HVP mode. Will the PIC program for the first time in this case? or do i need to take any additional care? I want everything to happen automatically.

 

[wp100]

Hi,

You need to say what hardware programmer and software you are using - A Pickit 2 /3 or something else ?

Assume you are taking about the 10/12/16 and 18F range of Pic chips ?

Also are you talking about programming a chip in a stand alone socket or in an existing circuit ? - there is a difference as Mlcre pin often needs extra circuitry when used in ICSP mode. See the Pickit2 user Guide.

 

[embeddedlover]

Using PIC18F series of microcontrollers. Also, using ICD debugger for programming.

Talking about on-board programming.

Have seen the pic kit user guide and ICD also, in those PGM itself is not connected.. So, does this need to be controlled manually? or any other option? Can we put PGM in programming mode forever?

 

[wp100]

Using PIC18F series of microcontrollers. Also, using ICD debugger for programming.

Talking about on-board programming.

Have seen the pic kit user guide and ICD also, in those PGM itself is not connected.. So, does this need to be controlled manually? or any other option? Can we put PGM in programming mode forever?

Hi,

Assume you mean you have the ICD2 as the ICD3 and Pk3 do have a connection for LVP.

Have never used the ICDs but believe the ICD2, like the PK2, can only do HVP and as such does not look at or use the PGM pin.

You often see comments where folk say tie the PGM pin to ground to ensure you use HVP mode, though think this is due to them trying every possible thing to overcome a problem not really related to the PGM pin, or where they are using a programmer that does have a LVP function.

I have programmed pics 16F and 18f chips for several years with my HVP Pk2 with the PGM pin left O/C in direct programming or in ICSP where the PGM pin is connected to some device, without any problems at all.