Delivered-To: joshybear@gmail.com Received: by 10.231.34.141 with SMTP id l13csp94450ibd; Sat, 14 Apr 2012 08:16:34 -0700 (PDT) Received: by 10.229.106.83 with SMTP id w19mr2185062qco.97.1334416582133; Sat, 14 Apr 2012 08:16:22 -0700 (PDT) Return-Path: Received: from pch.mit.edu (PCH.MIT.EDU. [18.7.21.90]) by mx.google.com with ESMTP id 1si11255997qaf.106.2012.04.14.08.16.21; Sat, 14 Apr 2012 08:16:22 -0700 (PDT) Received-SPF: pass (google.com: domain of piclist-bounces@mit.edu designates 18.7.21.90 as permitted sender) client-ip=18.7.21.90; Authentication-Results: mx.google.com; spf=pass (google.com: domain of piclist-bounces@mit.edu designates 18.7.21.90 as permitted sender) smtp.mail=piclist-bounces@mit.edu Received: from pch.mit.edu (pch.mit.edu [127.0.0.1]) by pch.mit.edu (8.13.6/8.12.8) with ESMTP id q3EFDjNY003708; Sat, 14 Apr 2012 11:13:49 -0400 Received: from mailhub-dmz-3.mit.edu (MAILHUB-DMZ-3.MIT.EDU [18.9.21.42]) by pch.mit.edu (8.13.6/8.12.8) with ESMTP id q3EFDh59003691 for ; Sat, 14 Apr 2012 11:13:43 -0400 Received: from dmz-mailsec-scanner-3.mit.edu (DMZ-MAILSEC-SCANNER-3.MIT.EDU [18.9.25.14]) by mailhub-dmz-3.mit.edu (8.13.8/8.9.2) with ESMTP id q3EFDfET008439 for ; Sat, 14 Apr 2012 11:13:43 -0400 Message-Id: <201204141513.q3EFDfET008439@mailhub-dmz-3.mit.edu> X-AuditID: 1209190e-b7f7c6d0000008c3-36-4f899425bf46 Authentication-Results: symauth.service.identifier Received: from authsmtp.register.it (authsmtp06.register.it [81.88.48.56]) by dmz-mailsec-scanner-3.mit.edu (Symantec Messaging Gateway) with SMTP id 86.E4.02243.624998F4; Sat, 14 Apr 2012 11:13:42 -0400 (EDT) Received: (qmail 29727 invoked from network); 14 Apr 2012 15:13:40 -0000 Received: from unknown (HELO Fabio.pop.bizzetti.info) (smtp@bizzetti.info@79.37.100.202) by authsmtp.register.it with ESMTPA; 14 Apr 2012 15:13:40 -0000 X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Sat, 14 Apr 2012 17:10:08 +0200 To: "Microcontroller discussion list - Public." From: Electron Subject: Re: [EE] Solution for slow Vcc rising on PIC321xx In-Reply-To: References: <201204140859.q3E8x6Jd025920@mailhub-dmz-1.mit.edu> Mime-Version: 1.0 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrHIsWRWlGSWpSXmKPExsUSGGFgoas2pdPfYNYEbYtv5x4xOzB6NJ05 yhzAGMVlk5Kak1mWWqRvl8CV0bz8E0vBdK6KaQcOszQwTuLoYuTkkBAwkXi2tZUJxGYUMJLY fe4VK0RcTOLCvfVsXYxcHEIClxklLjYsAysSEvCQWHWtlRkiMZtRoufKRKAODqAOQ4ntC1hA algEVCUudT0Bs0UEHCWWNy4H62UT0JC4snEdO4gtLGAl8ePxArA4p0CIxLKTvYwQM9sYJS51 nwSbySsgKPF3hzBIDbOAjsSC3Z/YJjDyz0LIzEKSWcDItIpRNiW3Sjc3MTOnODVZtzg5MS8v tUjXWC83s0QvNaV0EyMwwIQ4Jfl2MH49qHSIUYCDUYmHV9Csw1+INbGsuDL3EKMkB5OSKG/g xE5/Ib6k/JTKjMTijPii0pzU4kOMEhzMSiK8hb1AOd6UxMqq1KJ8mJQ0B4uSOK+a1js/IYH0 xJLU7NTUgtQimCwTB/shRhkODiUJ3p+TgLoFi1LTUyvSMnNKkNVwgggukDU8QGs2gBTyFhck 5hZnpkMUnWLU5Zh47dQVRiGWvPy8VClxXrvJQEUCIEUZpXlww2DJ4hKjrJQwLyMDA4MQD9A1 wEBAlX/FKA4MAGHeVJApPJl5JXCbXgEdwQR0BJ9CG8gRJYkIKakGRm2Dbcvkb7OzKRx7vDjY tPnCliLNaR5LY5KeFrPLhJaV9FxRnbdogbTNKYcteYVeN/+Kdl84JqHxlFVow1eheOku/+xV /tznXt/cx/JPLNrwV/SGLTPTNm+rZ9gY52LwsnDO3r+ipxTu7mO67mtdVSE9zfgncxKLrr8c 47S3bNdmvDr9+c37CiWW4oxEQy3mouJEAHolDIIRAwAA X-Topics: [EE] X-BeenThere: piclist@mit.edu X-Mailman-Version: 2.1.6 Precedence: list Reply-To: "Microcontroller discussion list - Public." List-Id: "Microcontroller discussion list - Public." List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: piclist-bounces@mit.edu Errors-To: piclist-bounces@mit.edu At 15.43 2012.04.14, you wrote: >I have had on two occasions, one on a volume production situation, had a >processor which would not start if supply rise time was too slow, even >though the data sheet said it should. Once Vdd had passed above a certain >level and non-starting had happened (it was an "even" which could be >observed) the processor would not start until the Vdd had been cycled to a >very low level - probably under about 0.2V. The system was powered by >human action (exercise bike) so slow start of the actual raw supply voltage >was not preventable. But would have the MPU started if you resetted it manually once power was good? >The only solution that worked for me was to make a supply starter which >isolated the processor Vdd and then applied power rapidly when adequate >voltage was available. I think the sartup circuitry used 2 or maybe 3 >jellybean transistors and a few passives and diodes. Probably cheaper in >production than a "power good" capable regulator. For me of concern is also the component count, both because space on the PCB is little, but also because I have to solder them (it's a small not so small serie) by hand, so the less tiny components I solder, the happier my hands are and the more boards I can do for unit of time. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist