I try to get running a RTC clock module with DS3231 and a pressure/temperature module with BMP180 under linux (Linux for Tegra, Kernel 3.10.40), which work fine under linux on other embedded arm systems with 3.3 V voltage (Vdd and Signal).
I use J3A1, pins 15 (GND), 16 (3.3 V), 18 (GEN2_I2C_SCL_3.3V) and 20 (GEN2_I2C_SDA_3.3V).
The RTC module “anderes” with time out and the BMP doesn’t answer at all.
How are you trying to access the devices? I am not familiar with the term “anderes”, but I assume that it is not good.
In particular, do the devices show up on the I2C bus correctly?
You can examine the bus:
sudo apt-get install libi2c-dev i2c-tools
For example: ( you have to determine which I2C bus to look at, it might be 0 or 1))
sudo i2cdetect -y -r 1
You should know which address it should show up at from the documentation provided with the devices. The DS3231 that I have uses 0x68
If you are trying to use the DS3231 as a real time clock, have you built an RTC Module for the kernel and installed it? Have you attached the device, i.e.:
$ echo ds3231 0x68 | sudo tee /sys/class/i2c-dev/i2c-1/device/new_device
so that you can read the time stored on the RTC?
$ sudo hwclock -r -f /dev/rtc1
Sorry, I use my android tablet (btw NVIDIA’s Shield tablet) for internet communications. The German android capitalizes, checks and corrects written English text as German! I hate it, but there is no way to turn it OFF completely! Anyway!!! It always stays active! :-(
The word “anderes” replaced my input “answers”!
I’ll check another things tomorrow…
Sorry, I was busy…
Meanwhile the RTC is running, the linux driver for DS3232 had dirty code.
But I have the problem with the pressure sensor BMP180 as before. The device is registered as an iio device ‘119l’, but the whole path ‘/sys/class/iio’ is missing. The Ubuntu iio utils access iio devices’ via this path!