gnupic: Thread: PIC18 K22 series chips

In December, I was successfully programming a PIC18F4525 with picp and a
Picstart Plus programmer.  I was having difficulty trying to get 2 UARTs running
at the same time, using the on-board UART for one, and software-emulating the
other.  Even at the maximum 32MHz on-board clock speed, there was just not
enough time for the interrupt routine and everything else to run (at 38400
baud).  I thought I would try the PIC18F45K22 instead, as it has two UARTs and
for the most part is structured rather like the 4525.  I new this was not a
supported device, but figured I could generate an entry for it in picdevrc, and
use picsnoop if all else failed.  Well, all else has failed, but so does
picsnoop, because I found out that Microchip does not support the Picstart Plus
with the K22 series chips.  My question is:  Is there something fundamentally
different about the K22 series that makes it incompatible with the Picstart
Plus?  There's nothing in the datasheet for the K22 chips that would suggest
that they program any differently from, say, the 18F4525.  If they do program
the same, then it may still be a shot in the dark figuring out how to make the
Picstart Plus program it, without any support from Microchip.  Any ideas?
                                             ---Tim

The nominal voltage for Vpp changed from 12V for the 18F4525 to 8.5V on 
the 18F45K22.  I don't know if the Picstart Plus can support that.  There 
may be more changes as well.

Personally, I'd just get a PICkit 2 and program with that.  That part is 
listed as supported if you use the standalone application.

Jerry

On Thu, 27 Jan 2011, Tim Edwards wrote:

> In December, I was successfully programming a PIC18F4525 with picp and a
> Picstart Plus programmer.  I was having difficulty trying to get 2 UARTs running
> at the same time, using the on-board UART for one, and software-emulating the
> other.  Even at the maximum 32MHz on-board clock speed, there was just not
> enough time for the interrupt routine and everything else to run (at 38400
> baud).  I thought I would try the PIC18F45K22 instead, as it has two UARTs and
> for the most part is structured rather like the 4525.  I new this was not a
> supported device, but figured I could generate an entry for it in picdevrc, and
> use picsnoop if all else failed.  Well, all else has failed, but so does
> picsnoop, because I found out that Microchip does not support the Picstart Plus
> with the K22 series chips.  My question is:  Is there something fundamentally
> different about the K22 series that makes it incompatible with the Picstart
> Plus?  There's nothing in the datasheet for the K22 chips that would suggest
> that they program any differently from, say, the 18F4525.  If they do program
> the same, then it may still be a shot in the dark figuring out how to make the
> Picstart Plus program it, without any support from Microchip.  Any ideas?
>                                             ---Tim
>
>
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Jerry,

> The nominal voltage for Vpp changed from 12V for the 18F4525 to 8.5V on 
> the 18F45K22.  I don't know if the Picstart Plus can support that.  There 
> may be more changes as well.
> 
> Personally, I'd just get a PICkit 2 and program with that.  That part is 
> listed as supported if you use the standalone application.

Thanks for the information.  I didn't notice the change in Vpp voltage. 
Microchip didn't go out of their way to advertise the differences between the
"K" series chips and others.  I am taking your advice and have ordered a PicKit
2 from Digi-Key.
                                             Regards,
                                             Tim

Jerry,

> The nominal voltage for Vpp changed from 12V for the 18F4525 to 8.5V on 
> the 18F45K22.  I don't know if the Picstart Plus can support that.  There 
> may be more changes as well.
> 
> Personally, I'd just get a PICkit 2 and program with that.  That part is 
> listed as supported if you use the standalone application.

I found out that even that comes with caveats.  The pic18F45K22 is listed as
supported by the PICkit 2, it's true.  I downloaded the pk2cmd-1.20 for Linux,
and discovered that the 18F45K22 is not among the devices listed in the
accompanying device file.  I found an updated device file on the Microchip
PicKit-2 web page, so I downloaded that.  It does list the 18F45K22.  Great so
far. . . so I plugged everything in and ran a blank check, and what do you know?
 It reports that the device file requires an updated version of pk2cmd. 
However, pk2cmd-1.20 IS the only version available on the Microchip website. 
Poking around the Microchip forums, I discovered that there is a test version
pk2cmd-1.21, but the forum only gave a pointer to a Windows version.  So I have
posted a reply on that forum thread, and we'll see how that goes.

    ---Tim

Wow, that's a surprise to me.  I hadn't actually tried, so I guess I 
should have mentioned that.

The readme in the windows version had something interesting in it:

This source is set up for Windows development of PK2CMD in Visual 
Studio, 
although all source files necessary for Linux and Mac OS builds are also 
included.  However, for building on these OS's it is recommended to 
download the v1.20 source titled specifically for them, as that archive 
contains a makefile and documentation specific to those Operating Systems.

There is a Makefile already in the windows zip.  I gave it a try, and it 
did build.  If you then grab the updated device file, it may work.  I don't have a 18F45K22 to test against, but it does 
tell me program memory is not blank when I test it with no board attached.

Jerry

On Mon, 31 Jan 2011, Tim Edwards wrote:

> Jerry,
>
>> The nominal voltage for Vpp changed from 12V for the 18F4525 to 8.5V on
>> the 18F45K22.  I don't know if the Picstart Plus can support that.  There
>> may be more changes as well.
>>
>> Personally, I'd just get a PICkit 2 and program with that.  That part is
>> listed as supported if you use the standalone application.
>
> I found out that even that comes with caveats.  The pic18F45K22 is listed as
> supported by the PICkit 2, it's true.  I downloaded the pk2cmd-1.20 for Linux,
> and discovered that the 18F45K22 is not among the devices listed in the
> accompanying device file.  I found an updated device file on the Microchip
> PicKit-2 web page, so I downloaded that.  It does list the 18F45K22.  Great so
> far. . . so I plugged everything in and ran a blank check, and what do you know?
> It reports that the device file requires an updated version of pk2cmd.
> However, pk2cmd-1.20 IS the only version available on the Microchip website.
> Poking around the Microchip forums, I discovered that there is a test version
> pk2cmd-1.21, but the forum only gave a pointer to a Windows version.  So I have
> posted a reply on that forum thread, and we'll see how that goes.
>
>    ---Tim
>
>
>
>
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>

Jerry,

> Wow, that's a surprise to me.  I hadn't actually tried, so I guess I 
> should have mentioned that.
> 
> The readme in the windows version had something interesting in it:
> 
> This source is set up for Windows development of PK2CMD in Visual Studio, 
> although all source files necessary for Linux and Mac OS builds are also 
> included.  However, for building on these OS's it is recommended to 
> download the v1.20 source titled specifically for them, as that archive 
> contains a makefile and documentation specific to those Operating Systems.
> 
> There is a Makefile already in the windows zip.  I gave it a try, and it 
> did build.  If you then grab the updated device file, it may work.  I don't
> have a 18F45K22 to test against, but it does  tell me program memory is not
> blank when I test it with no board attached.

Thanks for looking into that;  I would not have supposed that the Windows source
code would also compile under Linux, especially having written USB drivers for
both operating systems myself.  I should have thought to try that myself.  But
it's good to have the fact posted on a newsgroup where others can see it, too.

    Regards,
    ---Tim

Jerry,

In what I hope to be the final followup for this thread, I have successfully
programmed the PIC18F45K22 with the PICkit 2 programmer under Linux.  I must say
that I really like the PICkit 2 now that I've tried it, especially since there
does exist a command-line interface to drive it that I was trivially able to
replace "picp" with in the Makefile.  And the chip now programs in-system with
the (also trivial) addition of a 6-pin header super-glued to the underside of
the board.  Not to mention other useful features such as the fact that it
self-powers from the USB port, auto-detects chip types, etc.  Anyway, many
thanks for your help.

     Regards,
     Tim

Tim Edwards wrote:
> I would not have supposed that the Windows source code would also
> compile under Linux, especially having written USB drivers for
> both operating systems myself.

There are a few different ways to write portable USB drivers in
userspace. One is libusb, another is HIDAPI. More info at
http://libusb.org/


//Peter

No problem, glad I could help.

It's good to know it works, because I'll be set for my next PIC project 
then.

Jerry

On Tue, 1 Feb 2011, Tim Edwards wrote:

> Jerry,
>
> In what I hope to be the final followup for this thread, I have successfully
> programmed the PIC18F45K22 with the PICkit 2 programmer under Linux.  I must say
> that I really like the PICkit 2 now that I've tried it, especially since there
> does exist a command-line interface to drive it that I was trivially able to
> replace "picp" with in the Makefile.  And the chip now programs in-system with
> the (also trivial) addition of a 6-pin header super-glued to the underside of
> the board.  Not to mention other useful features such as the fact that it
> self-powers from the USB port, auto-detects chip types, etc.  Anyway, many
> thanks for your help.
>
>     Regards,
>     Tim
>
>
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