https://devzone.nordicsemi.com/f/nordic-q-a/20837/error-20-identifier-nrf_spis0-is-undefinedHi, After configuring the nRF51422 as a SPIS slave 0, we get the following error when trying to create the slave instance: static const nrf_drv_spis_t spis = NRF_DRV_SPIS_INSTANCE(SPIS0_INSTANCE_INDEX); /**&lt; SPI instance. */ ......\m_SPI_MIDIen-USTelligent Community 13Mon, 27 Mar 2017 13:57:00 GMThttps://devzone.nordicsemi.com/thread/81385?ContentTypeID=1Mon, 27 Mar 2017 13:57:00 GMT137ad170-7792-4731-bb38-c0d22fbe4515:f5af0813-2426-4d98-a71e-d2fb55767d76FredNovalia<p>Thanks, that was it. The code compiles now.</p> <p>Just a suggestion, maybe when the nRF51 target is selected, the SPIS0 could be greyed and disabled so the user cannot select it in the Configuration Wizard.</p> <p>Thanks again,</p> <p>Fred</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/81384?ContentTypeID=1Mon, 27 Mar 2017 13:46:21 GMT137ad170-7792-4731-bb38-c0d22fbe4515:df8eabc2-612e-443d-aed3-0a671d703cbcSigurd<p>Hi,</p> <p>On the nRF51 there is only 1 SPI slave, SPIS1, so you need to use SPIS instance 1 instead of 0:</p> <pre><code>#define SPIS_INSTANCE 1 /**&lt; SPIS instance index. */ static const nrf_drv_spis_t spis = NRF_DRV_SPIS_INSTANCE(SPIS_INSTANCE);/**&lt; SPIS instance. */ </code></pre> <p>From the nRF51422 Product Specification page 34:</p> <p><img src="https://devzone.nordicsemi.com/cfs-file/__key/communityserver-discussions-components-files/4/SPI_5F00_NRF51.png" alt="image description" /></p><div style="clear:both;"></div>