i2c

I am using the following I2C/GPIO Device driver to access the MCP23017 GPIOs. With the insmod command I am able to load the driver and its listed in /proc/modules. I have two MCP23017 chips connected to my Raspberry Pi. Both are detected at addresses 0x20 and 0x21 . The initcall to the driver registers the driver. I checked this by printing out a message. But the driver probe function is not called. The devices are not opened/ cannot be located elsewhere. How is the probe function called? Should the probe be done manually to locate the devices? Is the probe call similar to the open call? I

I am having a problem with the I2C driver for a Freescale p1022tw board. There is a command on U-Boot's console to read from an I2C device: i2c md chip address[.0, .1, .2] [# of objects] When I read 4 bytes from a device with id 0x60, at address 0x0, I get: tw=>i2c md 60 0 4 0000: 45 45 45 45 EEEE These values that it returned are wrong. I can get the right values if I read one byte at the time: tw=>i2c md 60 0 1 0000: 45 E tw=>i2c md 60 1 1 0001: 45 E tw=>i2c md 60 2 1 0002: 46 F tw=>i2c md 60 3 1 0003: 00 . I should have gotten 45 45 46 00 or EEF0 in the first command. In multiple readings

I am learning embedded development on the STM3220G-EVAL board with the STM32F207 microcontroller. I have tried to test the I2C interface by interfacing the two I2C2 and I2C3 modules on the same chip and sending/receiving a character. Here is the code I have currently written (using mdk-arm 5): #include <stm32f2xx.h> volatile uint8_t data = 'a', recv = 'x'; void i2c_init(void); void I2C2_EV_IRQHandler(void) { volatile uint16_t stat, dummy; stat = I2C2->SR1; switch(stat) { // SB set; read SR1 and write slave address in DR to clear case 0x01: dummy = I2C2->SR1; // Send address of slave I2C2->DR =

For my project I need the current time & date. Unfortunately the RP2 loses everything when it's turned off. The next thing is, that I won't have an internet connection to use NTP. For this reasing I need to implement a DS3231 RTC module. The communication of all devices runs over I2C (Raspberry <-> Arduino <-> DS3231). At the moment my Arduino communicates with the module and stores the date and time in char-arrays. The RP2 communicates with the Arduino to get the date/time. That actually works pretty good. But I'd like to communicate directly with the module to save ressources on the Arduino

There are many references to using i2c_smbus_ functions when developing embedded Linux software to communicate on the I2C bus. When i2c_smbus functions such as i2c_smbus_read_word_data are referenced in software project for ARM8 processor errors such as ‘ i2c_smbus_read_word_data’ was not declared in this scope are generated at compile. Investigation of the following header files indicate the absence of most i2c_smbus function definition. /usr/arm-linux-gnueabi/include/linux/i2c.h /usr/arm-linux-gnueabi/include/linux/i2c-dev.h Also in that following reference i2c.h file has all the i2c_smbus

I am trying to develop a driver for an embedded board. The driver is supposed to open up an interface for v4l2 and communicate with 2 devices using i2c . the driver will act as a master. I can't seem to understand how i2c_device_id array and i2c_add_driver functions work. I read documentation in kernel source but it won't help me on multiple slave clients. Do I have to have two seperate probe functions? Do i have to call i2c_add_driver two times? If not how am I going to be able to save two different clients to be able to send different bytes to different addresses. I am pasting my code here.

UPDATE: I can't even get this calculator to reproduce the SMBus PECs illustrated in figures 8 and 9 of this datasheet ! So I'm interfacing an arduino with a Melexis temperature sensor, and it's going okay--aside from the fact that I can't seem to get the CRC check to work. I've gotten read operations to complete successfully (although my software ignores the packet error code) but I have tried a lot of implementations of CRC8 to check the PEC byte to no avail. The code block I am using now came from OneWire: uint8_t OneWire::crc8(const uint8_t *addr, uint8_t len) { uint8_t crc = 0; while (len-

I have been working through some i2c examples. Plugging it all together and I find that I need to install the i2c-tools package, then use raspi-config to enable the I2C system. The wiringPi gpio command has a shortcut to the i2cdetect command and running it gives Before 3 weeks everything working properly, detected 68. I didn't understand what is the problem !!! Can anyone one help me to solve this issue. The I2C bus allows multiple devices to be connected to your Raspberry Pi, each with a unique address, that can often be set by changing jumper settings on the module. It is very useful to be