Subject: Re: New i2c framework
To: Eduardo Horvath <eeh@NetBSD.ORG>
From: Jason Thorpe <>
List: tech-kern
Date: 07/31/2003 08:53:02
On Thursday, July 31, 2003, at 08:43  AM, Eduardo Horvath wrote:

> Ick.  So instead of issuing one command to an intelligent I2C 
> controller
> you need to issue a dozen commands.  Doesn't that sort of defeat the
> purpose of having an intelligent I2C controller?

The intelligent controllers that I have encountered don't support this 
in any case.  The ones I have used basically support this:

	- START [write]
	- send address
	- send command byte [optional]
	- send command byte [optional]
	- read byte
	- read byte [optional]

i.e. no support for sending REPEATED START between the individual byte 
reads.  I also haven't encountered devices that require this, either.  
The ones that return multiple data bytes simply keep sending them until 
they see NACK from the master.

Do you have examples of devices that require the behavior you're 
talking about?

         -- Jason R. Thorpe <>