ESP8266 Community Forum

I have lolin v3
a few NFC card readers on the SPI bus
I was to add and SD card reader to the bus but several posts say that wont work (libray expects SD card has excluse use of bus)
there is another SPI bus on these boards, intended for an SD card or USB boot device.
can I get the SD reader working on those ports? I want it to just be an SD card reader rather than a boot device?

thans for any help.

Thank you for reaching out with your question regarding the LOLIN V3 board and the SPI bus. I understand that you currently have a few NFC card readers connected to the SPI bus, and you are interested in adding an SD card reader to the same bus. However, you've come across posts mentioning that this might not work as the library expects the SD card to have exclusive use of the bus.

Fortunately, the LOLIN V3 board has another SPI bus specifically intended for an SD card or USB boot device. This provides a potential solution to your situation. You can connect the SD card reader to this alternate SPI bus instead of the one where the NFC card readers are connected. By doing so, you can have the SD card reader function solely as an SD card reader, rather than a boot device.

Please refer to the board's documentation or specifications to identify the pins or connectors corresponding to the alternate SPI bus intended for the SD card or USB boot device. By utilizing this dedicated bus, you should be able to get the SD card reader working as desired without any conflicts with the NFC card readers.

If you encounter any difficulties or need further assistance during the setup process, I recommend consulting the board's documentation or reaching out to the manufacturer's support team for detailed guidance specific to your board model.

I hope this information helps you in achieving your desired configuration. Should you have any additional questions or concerns, feel free to ask.