---- START NEW MESSAGE --- Received: from cherry.ease.lsoft.com [209.119.0.109] by dpmail10.doteasy.com with ESMTP (SMTPD32-8.05) id AFE1A580068; Fri, 30 Jan 2004 13:42:57 -0800 Received: from PEAR.EASE.LSOFT.COM (209.119.0.19) by cherry.ease.lsoft.com (LSMTP for Digital Unix v1.1b) with SMTP id <22.00CC54B1@cherry.ease.lsoft.com>; Fri, 30 Jan 2004 15:50:42 -0500 Received: from MITVMA.MIT.EDU by MITVMA.MIT.EDU (LISTSERV-TCP/IP release 1.8e) with spool id 5481 for PICLIST@MITVMA.MIT.EDU; Fri, 30 Jan 2004 15:50:36 -0500 Received: from MITVMA (NJE origin SMTP@MITVMA) by MITVMA.MIT.EDU (LMail V1.2d/1.8d) with BSMTP id 9786; Fri, 30 Jan 2004 15:50:17 -0500 Received: from bay8-dav30.bay8.hotmail.com [64.4.26.87] by mitvma.mit.edu (IBM VM SMTP Level 430) via TCP with ESMTP ; Fri, 30 Jan 2004 15:50:17 EST X-Warning: mitvma.mit.edu: Host bay8-dav30.bay8.hotmail.com claimed to be hotmail.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Fri, 30 Jan 2004 12:50:19 -0800 Received: from 67.65.155.200 by bay8-dav30.bay8.hotmail.com with DAV; Fri, 30 Jan 2004 20:50:19 +0000 X-Originating-IP: [67.65.155.200] X-Originating-Email: [jsears2027@hotmail.com] X-Sender: jsears2027@hotmail.com References: <401AB745.7000405@yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1158 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 X-OriginalArrivalTime: 30 Jan 2004 20:50:19.0690 (UTC) FILETIME=[AC2500A0:01C3E772] Message-ID: Date: Fri, 30 Jan 2004 14:50:16 -0600 Reply-To: pic microcontroller discussion list Sender: pic microcontroller discussion list From: James Nick Sears Subject: Re: [PIC:] 16LF877A A/D To: PICLIST@MITVMA.MIT.EDU Precedence: list X-RCPT-TO: Status: U X-UIDL: 371856571 > What does the hardware look like? Sometimes one PIC will work properly > because its Analog Input can tolerate a high input impedance, whereas > most of the others can't. Make sure that the references are VERY well > filtered and that the input impedance is below 5K. A tiny cap can > usually solve the input impedance problem. I have 1uF caps on the analog inputs and Vref+ very close to the PIC. The analog inputs are fed with a LM60 temp sensor with a max output impedance of 800 ohms through about 20ft of ~24ga stranded wire. The reference is an LT1790 with about 3/8" of .010" PCB trace. All of this should be fine, right? > > It shouldn't be an issue, but Fosc/32 at 4mhz is a LONG time for a > conversion with a 10-bit A/D. You MIGHT be taking a lot longer than you > think.I should think Fosc/4 should be the outside clock window at 4Mhz. > I use the internal RC oscillator. I thought that this would be a case of the slower the better since I don't need to push the sampling frequency, but maybe I'll play with it. First after lunch I'm going to reprogram the board that was working with the firmware that the others are running (I actually think that it is the same or with only unrelated differences right now but I want to be sure). If it keeps working then it looks like I am in trouble. Thanks for the help, Nick > > --Bob > > > -- > > Replies: NOTE-Script, EXE,BAT and COM > files will be rejected by server > -------------- > Bob Axtell > PIC Hardware & Firmware Dev > http://beam.to/baxtell > 1-520-219-2363 > > -- > http://www.piclist.com#nomail Going offline? Don't AutoReply us! > email listserv@mitvma.mit.edu with SET PICList DIGEST in the body > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body .