Cypress Semiconductor Cy8CKIT-050 Cy8CKIT-050B ユーザーズマニュアル

CY8CKIT-050 PSoC® 5LP Development Kit Guide, Doc. # 001-65816 Rev. *E

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Code Examples

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Range is set to Vssa to Vdda in single-ended mode because the potentiometer output is a single 
ended signal that can go from 0 to Vdda. Therefore, at 12-bit resolution, the ADC will resolve in 

steps of Vdda/2

12

.

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Voltage Reference should be set to Vdda/2 supply voltage when input range is set to ‘Vssa to 
Vdda’. It is set to 1.65 V here, because by default Vdda jumper setting on the board is set to 3.3 
V. If J11 is changed to select 5 V, then this parameter should be changed to 2.5 V accordingly.

5.1.4

Verify Output

Build and program the code example, and reset the device. The LCD shows the voltage reading cor-
responding to the voltage on the potentiometer. 

 demonstrates the functionality. When you

turn the potentiometer, the voltage value changes. You can also verify the voltage on the potentiom-
eter using a precision multimeter.

Note The potentiometer connects to a differential ADC, which works in single-ended mode. This
means the ADC input is measured against internal Vssa. Any offset in the measurement can be pos-
itive or negative. This can result in a small offset voltage even when the potentiometer is zero.

Figure 5-3.  Voltage Display using SAR ADC

5.2.1

Project Description

This example code measures a simple analog voltage controlled by the potentiometer. The code
uses the internal Del-Sig ADC configured for a 20-bit operation; the ADC range is 0 to Vdda. The
voltage measurement resolution is in microvolts. The results are displayed on the character LCD
module.