Olimex Support Forum

OLinuXino Android / Linux boards and System On Modules => iMX233 => Topic started by: M-Reimer on September 29, 2013, 07:42:29 PM

Title: Trouble with i2c and interfacing mcp7941 RTC
Post by: M-Reimer on September 29, 2013, 07:42:29 PM
Hello,

can someone please help me with debugging an I2C problem?

I want to interface an mcp7941 RTC module. So at first, I need to get in contact with the module. I tried to find the address using "ic2detect -r 0" but no addresses are found to be existing...

Can someone give me some tips on how to get the I2C module working?

I use an Olinuxino Maxi which is jumpered for "Hardware I2C".
Title: Re: Trouble with i2c and interfacing mcp7941 RTC
Post by: M-Reimer on September 29, 2013, 09:46:59 PM
The problem was, that the RTC board, I use, has own SMD pullup resistors. I removed the pullups for SDA and SCL, which seems to have fixed my communication problems.

Next step will be to recompile the kernel with CONFIG_RTC_DRV_STMP=m to be able to blacklist the iMX233 builtin RTC and get my new RTC to be /dev/rtc0.