From: ScottEllis <sco...@gm...> - 2010-03-24 17:52:06
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You don't need a device driver to use the MCP23017. There is a working example right off the gumstix user wiki http://www.gumstix.net/wiki/index.php?title=Category:How_to_-_i2c Look down near the bottom for the overo-mcp23017 link. You'll need the user manual for the MCP23017 but you can google that. I chose that device for an I2C example deliberately just because it is so simple. Take a look at the manual, you'll see. coderdrone wrote: > > Interesting. In a separate email, it was suggested I use MCP23017. I was > unaware that there wouldn't be a linux driver for it. > > I don't deal with the hardware side of things here, so I'm not sure what > voltages things will be run at. The chart I am going by here lists the > MCP23017 connected to GPIO184 (I2C CLK) and GPIO185 (I2C DATA). Then a > separate listing of some buttons that will be on that bus listed as GPA0 - > GPA5. I don't know what GPIOs those GPA numbers would use. So I'm a bit > confused myself. > > On Wed, Mar 24, 2010 at 10:20 AM, Dave Hylands <dhy...@gm...> wrote: > >> Hi, >> >> On Wed, Mar 24, 2010 at 7:03 AM, <cod...@gm...> wrote: >> > How do I determine if the chip is supported by kernel drivers? I'm >> told >> > we'll be using the MCP23017. This is on Gumstix Overo. >> >> I did some googling and there doesn't appear to even be a linux driver >> for this chip. >> >> > The pins we were told to use on the expansion board are GPA# instead of >> > GPIO### (e.g., GPA0 vs. GPIO171). If these are exposed in >> > /sys/class/gpio/GPA# similarly to GPIOs, that would be great. >> >> I'm confused. Since this is an i2c bus, shouldn't you be connecting it >> to the i2c bus on the expansion board? The interrupt line(s) should go >> to a GPIO pin, but the SDA and SCL signals on the chip should connect >> to the SDA and SCL signals on the board. >> >> Will you be running the part at 1.8v? If so then you won't need any >> voltage converters between the chip and the expansion board. >> >> The GPIO pins are exposed in /sys/class only using their GPIO numbers. >> You won't see GPA0. You'll see GPIO171. >> >> -- >> Dave Hylands >> Shuswap, BC, Canada >> http://www.DaveHylands.com/ >> >> >> ------------------------------------------------------------------------------ >> Download Intel® Parallel Studio Eval >> Try the new software tools for yourself. Speed compiling, find bugs >> proactively, and fine-tune applications for parallel performance. >> See why Intel Parallel Studio got high marks during beta. >> http://p.sf.net/sfu/intel-sw-dev >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users >> > > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > -- View this message in context: http://old.nabble.com/Re%3A-I2C-tp27969201p28018896.html Sent from the Gumstix mailing list archive at Nabble.com. |