As stated in title, for a NodeMCU, Can I read an SD Card (SPI interface) on boot, then use D5,6,7 as GPIO after that is complete?
USER CASE: I have an Arduino program/sketch that uses D5,6,7 as GPIO inputs. I'd like to modify this program to read-only (no writes) some data from an SD Card at boot (using the standard SPI pins) to set some variables. After that, I would NEVER read from the SD Card. I assume that means that D8 (CS for the SPI) would never be asserted, and the SD Card would not 'care' if my inputs were driven high/low by an external switch.
FYI, the initial data on the SD Card would be written as a plain text file from a computer to set variables (WiFi SSID/PW, some email addresses, etc). So I will not be writing on the NodeMCU, and I won't ever read after initial boot (setup).
TIA-NTL2009