How many I2C ports does the BL65x support

The BL65x Data sheet lists two I2C controllers (up to 400 Kbps) are supported. The data sheet is provided as a hardware guide and refers to the hardware itself. The Nordic nRF528xx BLE mcu’s support multiple I2C controllers. However, the actual number of I2C interfaces depends on what SW is used for application development. If using smartBASIC for development there is one I2C instance and that instance is a master, there is no slave support.

Referring to the smartBASIC Extensions guide for the various BL65x modules it states:

Note I2COpenEx() allows for SCL and SDA to be routed to other GPIO pins.

This function uses the same I2C instance but allows changing the pins it is operating on. The smartBASIC I2C driver does not support a second instance. The intent of this function is so multiple devices with the same I2C address can be used. Some devices support a single address, some have multiple addresses they can use. If a sensor with 2 possible addresses is used then a third cannot be added on the same bus because the address of 2 devices will clash, but it can be used on different pins. Another example is if one sensor only supports 100KHz mode but another that supports 250KHz. Different busses would need to be used so that the 250KHz signals do not cause undefined operation for the 100KHz sensor

For applications developed using Nordic SDK or Nordic Zephyr SDK then I2C interfaces supported by the particular nRF528xx BLE MCU can be used. Both master and/or slave operation is also supported. Refer to the nRF828xx data sheet for details.