NVapi-write-value-to-monitor

Send commands to monitor over i2c using NVapi.
This can be used to issue VCP commands or other manufacturer specific commands

This program relies on the NVIDIA API (NVAPI), to compile it you will need to download the api which can be found here:
https://developer.nvidia.com/rtx/path-tracing/nvapi/get-started

History

This program was created after discovering that my display does not work with ControlMyMonitor to change inputs using VCP commands. Searching for an antlernative lead me to this thread rockowitz/ddcutil#100 where other users had found a way to switch the inputs of their LG monitors using a linux program, I needed a windows solution. That lead to the NVIDIA API, this program is an adaptation of the i2c example code provided in the API

Usage

Syntax

writeValueToDisplay.exe <display_index> <input_value> <command_code> [register_address]

Argument	Description
display_index	Index assigned to monitor by OS (Typically 0 for first screen, try running "mstsc.exe /l" in command prompt to see how windows has indexed your display(s))
input_value	value to write to screen
command_code	VCP code or other
register_address	Address to write to, default 0x51 for VCP codes

Example Usage

Change display 0 brightness to 50% using VCP code 0x10

writeValueToDisplay.exe 0 0x32 0x10 

Change display 0 input to HDMI 1 using VCP code 0x60 on supported displays

writeValueToDisplay.exe 0 0x11 0x60 

Change input on some displays

Some displays do not support using VCP codes to change inputs. I have tested this using values from this thread rockowitz/ddcutil#100 with my LG Ultragear 27GP850-B. Your milage may vary with other monitors, use at your own risk!

Change input to HDMI 1 on LG Ultragear 27GP850-B

NOTE: LG Ultragear 27GP850-B is display 0 for me

writeValueToDisplay.exe 0 0x90 0xF4 0x50

Change input to Displayport on LG Ultragear 27GP850-B

NOTE: LG Ultragear 27GP850-B is display 0 for me

writeValueToDisplay.exe 0 0xD0 0xF4 0x50