nrf52840 with Arduino over I2C

RE: nrf52840 with Arduino over I2C

Karl Ylvisaker — Thu, 24 Sep 2020 11:51:29 GMT

Hello,

[quote user="nshah88"]This is working. We are able to get the Slave address via the TWI scan example.[/quote]

Great, I am happy to hear that you are able to find the slave address of your connected device.
This means that the connection is correct, and the configuration of the connected device as a slave device is correct.

[quote user="nshah88"]One more question though: What should be passed in the first argument of nrf_drv_twi_tx? The argument requires: nrf_drv_twi_t const * p_instance?[/quote]

For the first argument of the function, you should pass your twi instance. You can see this being created at the very start of the example, in the line:

static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);

The TWI instance allocates memory to your TWI instance. You will need to pass this as an argument to most ( if not all ) the driver functions.

Lastly, as a side note, I recommend that you move to using the nrfx_twim driver directly, instead of using the legacy nrf_drv driver.

Best regards,
Karl

RE: nrf52840 with Arduino over I2C

Neel — Thu, 24 Sep 2020 08:44:31 GMT

[quote userid="87869" url="~/f/nordic-q-a/66261/nrf52840-with-arduino-over-i2c/271145"]As described in the example documentation, the nRF will output the results of the TWI bus scan to the terminal, where your Arduino device then should show up - if it is connected correctly and configured as a TWI slave.[/quote]

This is working. We are able to get the Slave address via the TWI scan example.

One more question though: What should be passed in the first argument of nrf_drv_twi_tx? The argument requires: nrf_drv_twi_t const * p_instance?

RE: nrf52840 with Arduino over I2C

Karl Ylvisaker — Wed, 23 Sep 2020 14:48:24 GMT

Hello,

As @Dmitry says - is your Arduino device configured as an TWI Slave device?
Furthermore, could you attempt to run the unmodified TWI Scanner example from the SDK while you are connected to your Arduino, and see if it is discoverable on the TWI bus?
As described in the example documentation, the nRF will output the results of the TWI bus scan to the terminal, where your Arduino device then should show up - if it is connected correctly and configured as a TWI slave.

Looking forward to resolving this issue together.

Best regards,
Karl

RE: nrf52840 with Arduino over I2C

Dmitry — Wed, 23 Sep 2020 08:32:57 GMT

Hi,

to configure Arduino as a slave, you need to pass its slave address to Wire.begin().