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Power down data save to EEprom - PIC

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Pommie

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I'm curious... why would having LVP ON require a warning?
I can't remember but it was something along the lines of debugging was not available with LVP enabled - actually, think that was MCLR disabled.

Mike.
 

danadak

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If you search for "LVP" in the datasheet you will see it has a number affects on the device.
\
Programming mode, reset.....to name a couple.

Part of the info -

1641261432266.png


Regards, Dana.
 
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tumbleweed

Active Member
I know what LVP does. My question was more to why would you want/need the IDE to issue a warning if it's enabled, like the last few posts were complaining about.
 

danadak

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Most Helpful Member
At the very least its a warning you are in ICSP programming mode on the chip.....


Regards, Dana.
 

tumbleweed

Active Member
Enabling LVP doesn't put you in any programming mode.
LVP simply means you don't require a HV (> VDD) on the MCLR signal to enable programming.
 

Nigel Goodwin

Super Moderator
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I know what LVP does. My question was more to why would you want/need the IDE to issue a warning if it's enabled, like the last few posts were complaining about.

Presumably it gives a warning because the VAST majority of people won't want it ON, presumably it's only ON by default because you wouldn't be able to reprogram the chip otherwise if you only had an LV programmer.

I've probably never seen the warning because I turn it OFF automatically :D
 

danadak

Well-Known Member
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Enabling LVP doesn't put you in any programming mode.
LVP simply means you don't require a HV (> VDD) on the MCLR signal to enable programming.
Thanks for correcting my error. Seems like it enables entry into programming, not puts you into it.

I should read my own posted ref material in the future :).


Regards, Dana.
 

tumbleweed

Active Member
I've probably never seen the warning because I turn it OFF automatically :D

I used to routinely turn it off too, but lately I've been changing that habit.
It seems that many of Microchips development boards that come with an onboard debugger/programmer (like the Curiosity LPC and Nano boards) require LVP, as does the SNAP programmer.

As you say, since you can't turn it off without HVP then it does no harm in trying, but you'll get errors in the mismatched config settings.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I used to routinely turn it off too, but lately I've been changing that habit.
It seems that many of Microchips development boards that come with an onboard debugger/programmer (like the Curiosity LPC and Nano boards) require LVP, as does the SNAP programmer.

As you say, since you can't turn it off without HVP then it does no harm in trying, but you'll get errors in the mismatched config settings.

The Nano boards have an on-board programmer/processor presumably if you've not got LVP set to ON, then that processor does it for you? - I've used a number of Nano board and never had any issues with LVP turned OFF, and I've never seen any requirement for it to be ON in the source code?.
 

tumbleweed

Active Member
The Nano boards have an on-board programmer/processor presumably if you've not got LVP set to ON, then that processor does it for you?
I have no clue anymore.
I tried a few combinations of boards/mplabx versions/device packs and got this when I tried to program a Curiosity HPC with LVP OFF:
Code:
The following memory area(s) will be programmed:
program memory: start address = 0x0, end address = 0x6ff
configuration memory
configuration memory
Address: 300006 Expected Value: 1 Received Value: 5
Failed to program device

Tried the same thing with a Curiosity Nano and it matches what you've seen... didn't care whether I set LVP ON or LVP OFF.
I suppose the later Nano just ignores the setting since it can't really turn it on or off.

MPLABX is like a box of chocolates...
 
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