RE: I2C Returning Same Wrong Value

Ole Bauck — Mon, 06 Feb 2017 13:07:59 GMT

When reading a register you should use repeated start (this is specified in the L3GD20 datasheet, repeated START (SR) condition). You can do this by setting no_stop to true in the twi tx function:

nrf_drv_twi_tx( ... , true);

Reading the WHOAMI (0x0F) register like Roger said is also a good idea to check that the twi connection to the chip is good.

RE: I2C Returning Same Wrong Value

Roger Clark — Mon, 06 Feb 2017 02:02:03 GMT

I suggest you simplify you code and write a test function that simply gets the value of the ID register (or something similar) in those devices (most devices have some sort of ID or WHOAMI register which contains a code that indicates what device it is)

Also.

I don't know about TWI, but for SPI, if the first byte of the data is the register number, the response is in rx_buf[1] not rx_buf[0]

Did you try looking in m_fromI2Cdevice[1]; (if your buff is longer than 1 byte)