https://devzone.nordicsemi.com/f/nordic-q-a/21688/nrf51-dk-can-i-use-both-twi-instances-as-well-as-an-spi-instanceI have a project where I need both TWI instances as well as an SPI instance to be used with sdcard and fatfs libraries. When I try to compile I get the error: SPI1_TWI1_IRQHandler if I have SPI1_ENABLED or SPI0_TWI0_IRQHandler if I have SPI0_ENABLED.en-USTelligent Community 13Thu, 27 Apr 2017 10:56:46 GMThttps://devzone.nordicsemi.com/thread/85181?ContentTypeID=1Thu, 27 Apr 2017 10:56:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:3c104a86-82aa-440c-a608-02483c7b40acSigurd<p>Hi,</p> <p>In the instantiation table in the <a href="https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.nrf51/dita/nrf51/pdflinks/ref_manual.html?cp=3_2">nRF51 Reference Manual</a> you can see that the TWI0 and SPI0 instance share the same base address/ID, and that TWI1 and SPI1 have the same base address/ID. That means that you cannot use both TWI instances + a SPI instance <strong>simultaneously</strong> on the nRF51, if you need that you will need to upgrade to nRF52832.</p> <p>But, if you enable <code>PERIPHERAL_RESOURCE_SHARING_ENABLED</code>, you can switch between using one of them (uninitialize one of them/ initialize the other). E.g. you can disable SPI1, enable TWI1, and when you are finished using TWI1 you can disable it and enable the SPI1 again.</p> <p>nRF51 instantiation table: <img src="https://devzone.nordicsemi.com/cfs-file/__key/communityserver-discussions-components-files/4/5_5F00_2_5F00_NRF51.png" alt="image description" /></p><div style="clear:both;"></div>