I2c multiplexer (tca9548a) interface with nrf52832

[Vijayneerukanti]

hello,

TCA9548A is the i2c multiplexer I am using. The problem statement is as follows:

The I2C multiplexer is connected to nRF52832 via twi communication. I2C multiplexer is 1 to 8 channel i2c multiplexer which selects each of the 8 channels at a time. 8 IMU sensors(MPU9250) are connected to each of the 8 channels. At a time a single IMU sensor reading has to be done, then the control goes to the net IMU sensor and so on upto 8 IMU sensors. I was able to write the driver code for the IMU sensor and I am able to read the readings of the single IMU sensor.

Coming to I2C multiplexer, every time one channel has to be selected and corresponding connected IMU sensor has to be read. My question is how to select each channel every time. The datasheet of the I2C multiplexer (tca9548a) has been attached herewith. 

Once we select the channel how to stall the control to that channel only? How will I send the MPU9250 address and reading commands via i2c multiplexer?7418.I2C_multiplexer_tca9548a.pdf

[haakonsh]

You need to first write to Control Register of the multiplexer on address 0x70 with a single byte containing the multiplexer state. See Figure 12. Control Register and Table 2. Command Byte Definition, in the TCA9548A datasheet. 

Then you can address the I2C slave as usual. 

[Vijayneerukanti]

Thank you for your reply.

Can I get a sample code/ pseudo code kind of thing for initializing the device? It will be helpful for me to code the device.

[haakonsh]

Invensense should have a generic C driver. And you will need to port the read/write function implementations to use our TWIM driver API.