Arduino pins

VFD pin	Arduino pin	Description
-	Vin	5V input, but is this correct? Shouldn’t we use the 5V pin?
-	3	test LED (blinking)
1	-	Filament F-
5	5V	Vdd, same for arduino Vdd. Should be 3.3V for ESP32
-	8	Vdisp-ON, to enable Vdisp, via the NPN-PNP high side, dual power rail transistor circuit
6	-	Vdisp, switched via PNP/P-channel transistor
7	GND	GND common ground
8	-	OSC circuit
9	9	RST reset pin
10	10	CS chip select SPI
11	13	CLK clock for SPI
12	11	DIN data input for SPI
45	-	Filament F+

SPI for the arduino UNO:

Pin	Code	Designation
10	CS	Chip select, might be any pin, but 10 is custom
11	MOSI	Master output, slave input. As the Arduino will be the master, this is connected to the DIN data input of the VFD
12	MISO	Master input, slave output. Not used (VFD communication is one way only). But as the SPI library read this input, we cannot use this pin!
13	SCLK	Serial clock, from the master