If you are using inbuilt ADC module of the micro-controller and mostly it will have 10 bit ADC. If you need 16 bit resolution, you need a module which have the capability of 16 bits resolution. There are many ic's which can do this. one is MCP3421 which has 18 bits of resolution. Connect MCP3421 to your controller using i2c and display the values with 16 bits of resolution.
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If you are using inbuilt ADC module of the micro-controller and mostly it will have 10 bit ADC. If you need 16 bit resolution, you need a module which have the capability of 16 bits resolution. There are many ic's which can do this. one is MCP3421 which has 18 bits of resolution. Connect MCP3421 to your controller using i2c and display the values with 16 bits of resolution.