From: Neil <picdude3@narwani.org>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
Sender: "piclist-bounces@mit.edu" <piclist-bounces@mit.edu>
Date: Tue, 20 Oct 2020 09:27:20 -0700
Subject: Re: [PIC] Crystal frequency selection
Thread-Topic: [PIC] Crystal frequency selection
Thread-Index: Adam/vzEFbf2htc+QealOVMtKDpBfQ==
Message-ID: <5F8F0FE8.2010908@narwani.org>
References: <5F8EF750.1010301@narwani.org>
	<0480a0b2-d285-10da-1349-b6b688d850b6@nicolaperotto.it>
In-Reply-To: <0480a0b2-d285-10da-1349-b6b688d850b6@nicolaperotto.it>
Reply-To: Microcontroller discussion list - Public. <piclist@mit.edu>
Accept-Language: en-US
X-MS-Exchange-Organization-SenderIdResult: Pass
X-MS-Exchange-Organization-PRD: mit.edu
X-MS-TNEF-Correlator:
received-spf: None (protection.outlook.com: narwani.org does not designate
	permitted sender hosts)
dkim-signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
 d=narwani.org	; s=default;
	h=Content-Type:In-Reply-To:MIME-Version:Date:Message-ID:From:
	Reply-To:To:References:Subject:Sender:Cc:Content-Transfer-Encoding:Content-ID
	:Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:
	Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe
	:List-Post:List-Owner:List-Archive;
	bh=a3mi3OaVUODzGd4oM9WyMKwYvPlEXdZWJVuBzY6iWWQ=;
	b=VeHMA2PZSknP0m0cabBSkonsZH
	cRu1T3SbU4+GjlkE/Zwj52y4D4IYGcsqCYC//x333GYiAeFZYtAXn02ogcco5qTalyqsMB/anlXSG
	AfXd7uSxs1z71DEVMSvbZtJ+V1tzEL1z5c3PiAxmlsb2h4INpsCat7XNeTMBmojrFOOgFlHhrtPyi
	0PufEW+0ndt6/Fvi2ImkBgv0hZrnSy8wiRYKL/S5NsHAxqWCxw6PvtPBmt5QdgUMtaq9i/yUQ2UPb
	C24YT974RxVuXj5UJTLPsZ6gfojw2HBpUhl3GP1twFc3cQh3GrWfs9/48yRkU997PTS/n8p9Kp1lG
	wSBXDH6Q==;
authentication-results: spf=none (sender IP is 68.65.123.241)
	smtp.mailfrom=narwani.org; mit.edu; dkim=fail (body hash did not verify)
	header.d=narwani.org; mit.edu;	dmarc=none action=none
 header.from=narwani.org; 
user-agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101
	Thunderbird/38.5.0
errors-to: piclist-bounces@mit.edu
list-id: "Microcontroller discussion list - Public." <piclist.mit.edu>
list-post: <mailto:piclist@mit.edu>
x-beenthere: piclist@mit.edu
x-mailman-version: 2.1.6
x-source-args:
x-source-dir:
x-antiabuse: Sender Address Domain - narwani.org
x-source:
x-authenticated-sender: premium47.web-hosting.com: ca4@narwani.org
x-topics: [PIC]
x-content-filtered-by: Mailman/MimeDel 2.1.6
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

I had also created my own, but it's been trial-and-error (xtal freq and=20
SPBRG value) to find a spot-on crystal.
Now, if your spreadsheet runs through DIgikey's crystal frequency=20
selections and picks the spot-on option for me, then you have my=20
attention :)

Cheers,
-Neil.



On 10/20/2020 12:08 PM, Nicola Perotto wrote:
> Hi Neil & all,
> I use the attached spreadsheet to calculate baud and errors.
> Enter values in yellow cells.
>       N
>
>
> On 20/10/2020 16:42, Neil wrote:
>> A bit academic, but this is bugging me... I was trying to get as close
>> to 115,200 baud on a PIC18F running at 64Mhz (or thereabouts).
>> At 64Mhz, best I can get is 0.8% error using SPBRG=3D34.
>> Calculating backwards, to get exactly 115,200, I can't find an "exact"
>> crystal.
>> Shouldn't I be able to find one of those "odd" values to get exactly
>> 115,200 baud at around 64Mhz?
>>
>> Cheers,
>> -Neil.
>>
>
>
>

--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.