From: Peter V. <pet...@gm...> - 2007-07-13 16:18:24
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Does anyone know which resistors are the pullup resistors for the I2C port on the basix? thanks, pete |
From: Dave H. <dhy...@gm...> - 2007-07-13 19:19:25
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Hi Peter On 7/13/07, Peter Vandrish <pet...@gm...> wrote: > Does anyone know which resistors are the pullup resistors for the I2C port > on the basix? I'm not sure - earlier versions didn't have any at all. My recollection is that the later motherboards have some rather weak (60K range) pullups, which you should be able to essentially ignore. When you add your own (1.5k to 10k) they will be what dominates. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |
From: Peter V. <pet...@gm...> - 2007-07-13 19:31:42
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so If I am going to hook up directly with a peripheral (acroname brainstem) then I dont have to remove the set of pullups on it. Thanks for you help On 7/13/07, Dave Hylands <dhy...@gm...> wrote: > > Hi Peter > > On 7/13/07, Peter Vandrish <pet...@gm...> wrote: > > Does anyone know which resistors are the pullup resistors for the I2C > port > > on the basix? > > I'm not sure - earlier versions didn't have any at all. My > recollection is that the later motherboards have some rather weak (60K > range) pullups, which you should be able to essentially ignore. > > When you add your own (1.5k to 10k) they will be what dominates. > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ > > ------------------------------------------------------------------------- > This SF.net email is sponsored by DB2 Express > Download DB2 Express C - the FREE version of DB2 express and take > control of your XML. No limits. Just data. Click to get it now. > http://sourceforge.net/powerbar/db2/ > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Peter V. <pet...@gm...> - 2007-07-13 19:36:48
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sorry, I forgot to mention that the brainstem itself has a set of pullup resistors tied to a 5 volt rail. On 7/13/07, Peter Vandrish <pet...@gm...> wrote: > > so If I am going to hook up directly with a peripheral (acroname > brainstem) then I dont have to remove the set of pullups on it. > Thanks for you help > > > On 7/13/07, Dave Hylands <dhy...@gm... > wrote: > > > > Hi Peter > > > > On 7/13/07, Peter Vandrish < pet...@gm... > wrote: > > > Does anyone know which resistors are the pullup resistors for the I2C > > port > > > on the basix? > > > > I'm not sure - earlier versions didn't have any at all. My > > recollection is that the later motherboards have some rather weak (60K > > range) pullups, which you should be able to essentially ignore. > > > > When you add your own (1.5k to 10k) they will be what dominates. > > > > -- > > Dave Hylands > > Vancouver, BC, Canada > > http://www.DaveHylands.com/ <http://www.davehylands.com/> > > > > ------------------------------------------------------------------------- > > > > This SF.net email is sponsored by DB2 Express > > Download DB2 Express C - the FREE version of DB2 express and take > > control of your XML. No limits. Just data. Click to get it now. > > http://sourceforge.net/powerbar/db2/ > > _______________________________________________ > > gumstix-users mailing list > > gum...@li... > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > > |
From: Dave H. <dhy...@gm...> - 2007-07-13 19:43:40
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Hi Peter, On 7/13/07, Peter Vandrish <pet...@gm...> wrote: > > sorry, I forgot to mention that the brainstem itself has a set of pullup > resistors tied to a 5 volt rail. Ahh - that's not good. The gumstix runs at 3.3v, so if you're connecting the brainstem up directly, you should remove the resistors on the brainstem and add resistors which pullup to 3.3v The i2c on the robostix runs at 5v (it has an i2c 3.3v to 5v converter), and it has built-in pullups. -- Dave Hylands Vancouver, BC, Canada http://www.DaveHylands.com/ |