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Pic18lf4520

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Mechaman

New Member
Ok so im trying to program this PIC through my pickit2. It can not find the device. I checked the supported PIC's list and it shows nothing of the 18LF's but it does show the 18F's. I was told a while back that i should buy the 18LF's as it would work with my PICKit2. All the wires are set up correctly, what am i doing wrong?
 

be80be

Well-Known Member
It doesn't list it but i don't see why you couldn't set the volts to 3 volts and manually
set it for a 18f4520 and program it that way
 

Wp100

Well-Known Member
Like all Microchip PIC18 devices, members of the
PIC18F2420/2520/4420/4520 family are available as
both standard and low-voltage devices. Standard
devices with Enhanced Flash memory, designated with
an “F” in the part number (such as PIC18F2420),
accommodate an operating VDD range of 4.2V to 5.5V.
Low-voltage parts, designated by “LF” (such as
PIC18LF2420), function over an extended VDD range
of 2.0V to 5.5V.
If using a stand alone programmer then program the chip at 5v, the recommended way.

If programming it in a 3v circuit, then pre set the voltage selector to 3v in 'VDD PICKIT2' on the Pickit2 programmer before connecting to the circuit.

The LF devices are always recognised by the Pickit2 as F versions
 
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be80be

Well-Known Member
I don't no if your pickit2 is not like mine but if you put a 18lfxxx it sets the voltage to 2.5volts and tells me what chip i have it hooked to and
the recommended way.
is for your programmer to verify at the voltage it will be running on which is not 5volts if it is a LF chip so he may have to do it manually. If it's not showing this chip
I have had to do that before. On some pickie chips.
 
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Wp100

Well-Known Member
Hi Burt,

I'm using a Microchip PK2 and V2.61 software & 2.32 firmware.

Have just tried every option, with a LF4620, but it always comes up with +5v in the Pk2 VDD box, unless it senses a lower target voltage.

I seem to remember that it did things differently on an earlier software release.

As for the +5v ' recommended way' I'm sure I read that on Microchips site or PK2 forum but cannot find the entry to quote now.

Also from the Microchip site or forum was the point about pre setting VDD to the lower target voltage if using icsp - this was to avoid any chance of the default +5v being applied if a operator miskake was made, particularly if used as programmer-to-go

Be interested to know if you are using an earlier version..
 
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be80be

Well-Known Member
intelligent programmers that can verify the device at several supply voltages
If you program a pic LF you want to verify at the voltage it is going to run and I have use most all of the pickit2 frimware and software I have ver 2.61
It's not going to program any lower then what it takes to do the job. What I will do is verify that the chip will run at lower voltage. And all I was telling him is to set it manually For a 18f4520 program and verify at the voltage it will run at when installed And he should be good to go.
Ok so im trying to program this PIC through my pickit2. It can not find the device.
He can't find it because it's not listed a 18f4520 is but no 18lf4520 but a 18f4520 setting should program it just fine just make sure you verify at the voltage it will be running at or it may not run.
 
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Wp100

Well-Known Member
Hi,

If you program a pic LF you want to verify at the voltage it is going to run
Thanks for coming back - fair comment too - I've have only used LF chips on the test bench - and am happy to take your point.
 

Wp100

Well-Known Member
Good that you got it programmed up :)

The 18LF chips are handy - you have the more convenient instruction set / memory allocation over the 16 range and apart from being able to use it in 5v circuits, you can use it at 3v or 3v3 with many of the new low voltage i/o devices like Sd cards, memory chips etc.

A lot of code on the web is done for the 16F range but its usually easy enough to manually convert them to run on the 18Fs
 
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