https://devzone.nordicsemi.com/f/nordic-q-a/65389/nrf24l01-compatibility-with-1-8v-ucI would like to use the NRF24L01+ from a 3v coin cell, but interface it over SPI with a 1.8v-powered microcontroller. Assuming the uC is tolerant of the NRF SPI outputs, I am wondering if the SPI inputs to the NRF will reliably work if they are 1.8v?en-USTelligent Community 13Mon, 31 Aug 2020 07:29:34 GMThttps://devzone.nordicsemi.com/thread/267132?ContentTypeID=1Mon, 31 Aug 2020 07:29:34 GMT137ad170-7792-4731-bb38-c0d22fbe4515:28058008-b344-4369-ab05-8449d07ba2a7H&#229;kon Alseth<p>Hi,</p> <p>&nbsp;</p> [quote user="mattgaidica"]My proposed solution is to instead use a 1.9v regulator for my uC, which will also meet the power supply demands of the nRF24L01+ and make the SPI bus operate at&nbsp;1.9v.&nbsp;[/quote] <p>This would be a less intrusive workaround (space-wise), compared to a lvl shifter.</p> <p>I would recommend that you keep the VDD_NRF a bit higher than the minimal voltage (1.9 + 0.1 V, for instance), to account for any dips or ripple in the supply.&nbsp;</p> <p>&nbsp;</p> <p>Kind regards,</p> <p>Håkon</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/267100?ContentTypeID=1Sun, 30 Aug 2020 17:47:19 GMT137ad170-7792-4731-bb38-c0d22fbe4515:8718db96-8db6-4bf4-aaa0-7e4664ecd726mattgaidica<p>It appears this would be problematic since &quot;Table 12. Digital input pin&quot; states that &quot;high level&quot; = 0.7*VDD, in this case, 0.7*3v=2.1v, which is less than 1.8v. Therefore, 1.8v logic would not be reliable on the SPI pins. My proposed solution is to instead use a 1.9v regulator for my uC, which will also meet the power supply demands of the nRF24L01+ and make the SPI bus operate at&nbsp;1.9v.&nbsp;</p><div style="clear:both;"></div>