I'm trying to use an nRF51-DK board (PCA10028) setup as a slave using either I2C or SPI, but it doesn't look like that is possible using the libraries. Is there something in the hardware that prevents this or was it just not implemented?
The hardware can do it, there's just no software support at the moment. A good rule of thumb is that if the Arduino Zero can't do it, neither can this project.
I'm trying to use an nRF51-DK board (PCA10028) setup as a slave using either I2C or SPI, but it doesn't look like that is possible using the libraries. Is there something in the hardware that prevents this or was it just not implemented?