[GPS_Standard] PIC18F2220 versus PIC18F2221

[Bert, VE2ZAZ]

Hi All,

I have spent some time this morning trying to see the differences in the timers between the two devices and could not see any. Three of the total 4 timers can run in 16-bit mode and two of these 4 can run in 8-bit mode. Same features associated to each of them. 

One difference is the Enhanced USART vs Addessable USART, which brings auto Baudrate detection. But I am pretty sure the must have made the EUSART compatible (by default) withy the AUSART. 

One area I would spend more time on is the configuration bits. Several new bits were added. This is where I suggest working. One bit affects Timer 1, which is the one used for the 10MHz frequency capture feature. Also make sure y DO NOT invoke the Extended Instruction set (XINST).

Other small differences appear to reside in the Power up reset, the NanoWatt stuff, etc. These should not affect counting operation.

I may order one 2221 to try it out, but this is not going to happen in the near term. You will probably find the solution before I can try anything...

Have fun!

Bert, VE2ZAZ
http://ve2zaz.net

----------------------------------------
> From: martein at xs4all.nl
> To: gps_standard at mailman.qth.net
> Date: Mon, 17 May 2010 16:45:51 +0200
> Subject: Re: [GPS_Standard] GPS_Standard Digest, Vol 34, Issue 1
>
> Hi Roberto,
>
> I think that is an error in the datasheet overview of the 2221. I have
> recompiled the firmware with the 18F2221 include file and I had to fix 3
> errors having to do with different names of the configuration bits.
>
> Now when I use this new firmware compiled for 2221, I have exactly the same
> result. It does not count properly. The hexfiles only differ for the bits
> that describe the configuration bits. And that is correct that is also a
> visible difference the datasheet.
>
> If you go through the datasheets of the 2220 and 2221 side by side on the
> pages that describe the timer counter hardare, there is no difference to be
> found.
>
> I am going to leave it now. I am not a PIC expert and don't want to become
> one Hi!
>
> Best 73's,
> Martein
> pa3ake
>
> ----- Original Message -----
> From: "Roberto Barrios" 
> To: 
> Sent: Monday, May 17, 2010 4:20 PM
> Subject: Re: [GPS_Standard] GPS_Standard Digest, Vol 34, Issue 1
>
>
>> Hi Martein,
>>
>> Now I'm not so sure... Looking at page 3 (as per AdobeReader) of the
>> 18F2220
>> datasheet, lower right corner, you can read "timers 8/16bit: 2/3", but
>> there
>> is no more info on the fifth counter, in page 10 it says this part has 4
>> timers. Now I am not sure where the issue is.
>>
>> Regards,
>> Roberto EB4EQA
>>
>> -----Original Message-----
>> From: gps_standard-bounces at mailman.qth.net
>> [mailto:gps_standard-bounces at mailman.qth.net] On Behalf Of
>> gps_standard-request at mailman.qth.net
>> Sent: domingo, 16 de mayo de 2010 18:00
>> To: gps_standard at mailman.qth.net
>> Subject: GPS_Standard Digest, Vol 34, Issue 1
>>
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>> Today's Topics:
>>
>> 1. PIC18F2220 versus PIC18F2221 (Martein Bakker)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Sat, 15 May 2010 21:47:28 +0200
>> From: "Martein Bakker" 
>> Subject: [GPS_Standard] PIC18F2220 versus PIC18F2221
>> To: 
>> Message-ID: <574096AB150146CFBD63DFAE3EFE9A85 at mhbp5q>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> Hi list!
>>
>> I have succesfully built the VE2ZAZ GPS standard.
>>
>> Initially I used PIC18F2221 as I could not get PIC18F2220. The 18F2221 is
>> supposed to be the newer and better part and successor of 18F2220. I went
>> through the datasheets and could not see any difference that would prevent
>> the 18F2221 to work in this application. However it failed to work
>> partially
>> in practice. Montrol software could talk with it, but the measured
>> frequency
>> was always 0 and strange enough the frequency difference was not 0, but
>> the
>> MSB byte was always 0! Obviously it did not lock.
>>
>> Does anyone know why the 18F2221 does not work with this application? It
>> would be great if the firmware is compatible with this device as it is
>> much
>> cheaper.
>>
>> Best regards
>> Martein
>> pa3ake
>>
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