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Re: [Gumstix-users] g418
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From: albertd <alb...@sy...> - 2005-03-10 04:20:33
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I think David has it right: There is one /dev/i2c-? node per i2c *bus*
and an ioctl is used to select the slave unit on the bus to connect to.
I have trivially adjusted my devices to build only 3 of the nodes since
that is all I expect to ever need even if I resort to bitbanging a
couple with GPIOs
Index: sources/device_table.txt
===================================================================
--- sources/device_table.txt (revision 422)
+++ sources/device_table.txt (working copy)
@@ -68,7 +68,7 @@
/dev/ttyS c 666 0 0 4 64 0
1 4
/dev/fb c 640 0 5 29 0
0 32 4
/dev/rfcomm c 666 0 0 216 0 0
1 4
-/dev/i2c- c 666 0 0 89 0 0
1 255
+/dev/i2c- c 666 0 0 89 0 0
1 2
#/dev/ttySA c 666 0 0 204 5 0
1 3
#/dev/psaux c 666 0 0 10 1 0
0 -
#/dev/ppp c 666 0 0 108 0 -
- -
On the side: has anyone got a i2c real time clock they would recommend?
I would prefer one with battery backup on a semi-independant board
rather than one I would have to build up from components.
Albert.
David Farrell wrote:
>--- Craig Hughes <cr...@hu...> wrote:
>
>
>>On Mar 8, 2005, at 7:50 PM, David Farrell
>>wrote:
>>
>>
>>
>>>I2C looks disabled, well enough...
>>>
>>>I know this was added some time ago but why
>>>
>>>
>>are
>>
>>
>>>there so many I2C devices?
>>>
>>>
>>I think because in theory you could have that
>>many.
>>
>>C
>>
>>
>
>I'm a litle confused. In the kernel
>documentation (dev-interface) it seems to
>indicate the -0 is the host, not the device. You
>need ioctl to specify device address. It is only
>the i2c kernel module i2c-dev that is used right?
>
>David.
>
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