How to measure accurate value for resistive touch with ADC
Posted: 01 Apr 2019, 14:55
The NuMaker emWin M487(NK-BEDM487D) is using resistive touch to implement HMI.
https://direct.nuvoton.com/tw/numaker-emwin-m487
First user need to consider how to get the accurate value of ADC. Please follow below steps:
1. Make certain Vref of chip is right
2. Please refer to M480 TRM and set EXTSMPT to get enough sampling time. It does not impact the conversion performance when with enough sampling time.
How to get the position of the X axis?
One side(XL) is set to low, and another one(XR) need to set to high. YD should be set to floating, then we can get value of the X axis.
How to get the position of the Y axis?
Just like how to get X axis.
https://direct.nuvoton.com/tw/numaker-emwin-m487
First user need to consider how to get the accurate value of ADC. Please follow below steps:
1. Make certain Vref of chip is right
2. Please refer to M480 TRM and set EXTSMPT to get enough sampling time. It does not impact the conversion performance when with enough sampling time.
How to get the position of the X axis?
One side(XL) is set to low, and another one(XR) need to set to high. YD should be set to floating, then we can get value of the X axis.
How to get the position of the Y axis?
Just like how to get X axis.