unfortunately my HMOSI, HMISO, HCS and HSCLK pins (GPIO12-15) on NodeMCU are occupied using swapped Serial port (to be able to have a serial device connected and use USB for debugging at the same time).
Is there an alternative to connect my SD-Card Modul via SPI?
What about the MOSI, MISO, CS and SCLK pins? As far as I could figure out, they cannot be used?
Those pins are used for talking to the flash memory; they are not usable for other stuff. That row of 6 pins on the short side of the module isn’t really usable.
Two of them are available if it’s configured and wired for dio instead of qio (but qio executes code significantly faster) - some modules are wired for qio, some aren’t. Often you don’t know which until you try to upload with qio and find that it doesn’t work. I recently had to take a torch to some wemos d1 minis to remove the module so I could replace it with one that supported qio…
Do you really need the SD card? You have 3MB available in the SPIFFS.
The SD Card is for logging purposes...
Important is an easy way to daily log data and transfer it to the PC for people, who has no technical background. So I suppose an SD Card is the best way to do that.
Probably I will test everything without SD-Card with the Serialport swapped, as Pieter explained in another Post. I don´t expect big difficulties writing the data to SD so probably during development I don´t need it connected all the time. And when the SD-Card-Modul will be connected, I will write a log to the SD itself.
I also tried to have a telnet-Server on the NodeMCU (NodeMCU in WiFi-AP mode) for debugging messages via telnet but I was not able to connect with my Computer so finally I gave up.
Thanks for your help so far!
you could offer a web page for download of the log file like I do in my project