SPI LCD (U8G2) with SPI Counter Connection Issue

Other Hardware Displays
2

Usually you can not combine Software emulated (bitbanging) SPI with Hardware driven SPI:
Instead of

U8G2_UC1701_MINI12864_F_4W_SW_SPI u8g2(U8G2_R0, /* clock=*/ 13, /* data=*/ 11, /* cs=*/ 2, /* dc=*/ 3, /* reset=*/ 4);

try

U8G2_UC1701_MINI12864_F_4W_HW_SPI u8g2(U8G2_R0,/* cs=*/ 2, /* dc=*/ 3, /* reset=*/ 4);

This will also speed up refresh rate for the LCD.

Oliver