From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lorien.elatec.si ([193.77.58.106] helo=lorien.ee.epico.si) by canuck.infradead.org with esmtps (Exim 4.63 #1 (Red Hat Linux)) id 1HoiAN-0002wc-Mi for linux-mtd@lists.infradead.org; Thu, 17 May 2007 11:45:28 -0400 Received: from [192.168.0.3] (telperion.ee.epico.si [192.168.0.3]) by lorien.ee.epico.si (8.12.11.20060308/8.12.11) with ESMTP id l4HFjCcd016408 for ; Thu, 17 May 2007 17:45:13 +0200 Message-ID: <464C788A.8020209@users.sourceforge.net> Date: Thu, 17 May 2007 17:45:14 +0200 From: Savin Zlobec MIME-Version: 1.0 To: linux-mtd@lists.infradead.org Subject: Re: Problems with ST NAND512W3A nand flash References: <464B17F3.9040804@users.sourceforge.net> In-Reply-To: <464B17F3.9040804@users.sourceforge.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Savin Zlobec wrote: > Hi All! > > I am working on a AT91RM9200 based board with ST NAND512W3A2B flash. > Kernel version is 2.6.19.7 with patches from maxim.org.za/at91_26.html. > Everything works perfectly, except for boot time NAND chip > identification which fails every once in a while. NAND signature > is 0x20 0x76, but sometimes I get 0x20 0x20. My first guess was > timing problems, but I've double checked everything and all signals > are inside the specs. I've also tested the chip with shorter and > longer setup, hold and pulse times for read and write, but without > any success. Trying different kernels didn't help either. After some debugging I found what it looks like a silicon bug in ST NAND512W3A2B. It looks like this particular chip doesn't handle well the ALE and CLE transitions (no R or W) when in the middle of READID command - other commands seem not affected. I have the nand wired to AT91RM9200 according to the datasheet - ALE and CLE go to A21 and A22. AT91RM9200 errata #34 states that the address bus is continuously active, even if the address is an internal one - so A2[12] toggle often. Sometimes it happens that signature reading gets interrupted and if there is an transition on A2[12] ... BOOOM - No NAND device found!!! Regards, savin