I have a LCD display VMA412 unused for a long time due to lack of suffiecient documentation. By trying with supplied test programs (many of them not directly working) I could verify many details important to the user but not shown on the very short manual. Why is Velleman’s policy not to show the schematics. What is the pinout of P2 and the signals ( pin 1 is 3.3V, pin 2 is GND, pin 3 is SD_DO, pin 4 is SD_DI etc). Are the outputs limited to 3.3V to be able to connect to e.g. ESP-devices. What is the current consumption. What is the function of 2 '245 type buffers partly connected to P2. Touch screen properties and calibration need more information. It would take several hours to work out the schematics risking to break the LCD.
Not known / described anywhere but can be easily measured (measuring consumption of the UNO with and without VMA412).
Are the outputs limited to 3V3 to connect eg to ESPs?
To my knowledge, the only outputs of the VMA412 are four analog lines coming from the touch screen. VMA412 is developed for UNO / Mega and that work on 5V.
“P2” or CON1 should not be connected for normal use.
Here you find a diagram: https://www.velleman.eu/downloads/29/vma412_diagram.pdf
Code and library update: https://www.velleman.eu/downloads/29/vma412_code_and_library_update.zip
Normally the demo codes should work well.