Date: Thu, 7 Jun 2007 10:06:57 +0200 (CEST) From: =?iso-8859-1?Q?Bj=F6rn_K=F6nig?= <bkoenig@alpha-tierchen.de> To: "Neil Bradley" <nb@synthcom.com> Cc: arm@freebsd.org Subject: Re: 4-bit SD Card mode Message-ID: <53054.2001:6f8:101e:0:20e:cff:fe6d:6adb.1181203617.squirrel@webmail.alpha-tierchen.de> In-Reply-To: <20070607005128.T43808@synthcom.com> References: <50503.2001:6f8:101e:0:20e:cff:fe6d:6adb.1181202550.squirrel@webmail.alpha-tierchen.de> <20070607005128.T43808@synthcom.com>
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Neil wrote: > I've done SD drivers, both 1 and 4 bit, DMA and programmed I/O, on the > PXA270, Atmel SAM7, Atmel SAM9, and Freescale MX31 CPUs. How may I be of > assistance? Actually the driver does the whole status and error handling using an interrupt service routine. This is unsuitable in 4-bit mode because in this mode the interrupt line is shared with a data line. So to get 4-bit mode working it is necessary to know the complete definition of the "interrupt period" - the period where it is allowed to enable the interrupt during 4-bit mode. Björn
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