From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: 8xx i2c refers to unspecified chip errata In-Reply-To: <3DA5A858.50802@embeddededge.com> To: Dan Malek Date: Thu, 10 Oct 2002 10:35:42 -0600 (MDT) Cc: joakim.tjernlund@lumentis.se, Barker Michael-r43496 , linuxppc-embedded@lists.linuxppc.org MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Message-Id: <20021010163542.A6F4027C52@chuy.ouraynet.com> From: craig@hollabaugh.com (Dr. Craig Hollabaugh) Sender: owner-linuxppc-embedded@lists.linuxppc.org List-Id: > Joakim Tjernlund wrote: > > > .... The driver(i2c-algo-8xx.c) that > > comes with the kernel has other severe bugs(memory corruption etc.) as well. > Dan Wrote > Just toggle the bits in software. I never saw an application where the I2C > controller provided a performance advantage. It's lots of software to execute, > along with all of the interrupt handling and stuff, so you just spend lots of > overhead not making any other progress. > > Make sure you carefully analyze the entire system performance advantages. > Using the controller assitance just because it is there isn't always the > proper solution. Same is true for the SPI. Here's a link to my book's I2C bit banging code for 8xx http://www.embeddedlinuxinterfacing.com/chapters/10/SAA1064_rpxcllf.c You can pull the I2C routines from this code. Let me know if you have any questions. Craig ** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/