https://devzone.nordicsemi.com/f/nordic-q-a/17922/can-nrf51822-master-spi-clock-use-8mwe follow the nRF51_Series_Reference_manual v3.0, set the master SPI clock to 8M. but found when in mode 0, the MOSI change near at SCLK rise edge, not in fall edge. our hardware engineer found this: the master SPI clock be 4M in section 8.9 in nRF51822_PSen-USTelligent Community 13Wed, 23 Nov 2016 08:37:50 GMThttps://devzone.nordicsemi.com/thread/69097?ContentTypeID=1Wed, 23 Nov 2016 08:37:50 GMT137ad170-7792-4731-bb38-c0d22fbe4515:ba7fbc67-e7c8-4138-ad82-9fdd21f96038Petter Myhre<p>I think <a href="https://devzone.nordicsemi.com/question/2990/spi-master-speed-of-nrf51822/">this</a> answers your question.</p><div style="clear:both;"></div>