opamp_fast_lpadc#
Overview#
The OPAMP lpadc example demonstrates how to use the OPAMP driver. In this example, the reference voltage (Vref) of the OPAMP1 non-inverting input port comes from the output port of OPAMP0, which needs to be connected to an LPADC channel, the OPAMP1 non-inverting input port needs to be connected to a voltage source and an LPADC channel, the OPAMP1 inverting input port needs to be connected to GND, and the OPAMP1 output port needs to be connected to an LPADC channel.
When this example runs successfully, the terminal will print the OPAMP0 output port voltage value, the OPAMP1 non-inverting input port voltage value, the OPAMP1 output voltage value measured using lpadc, and the theoretical OPAMP1 output value.
The theoretical calculated value should be very close to the value measured by LPADC.
OPAMP1 input and output relationship formula: Vout = Vref + (R2 / R1 * (Vp - Vn)).
Supported Boards#
FRDM-MCXA346
Hardware requirements
Type-C USB cable
FRDM-MCXA346 board
Personal Computer
Board settings Please connect SJ1 to B type (2-3). Please connect OPAMP1 positive input channel (SJ4 port 3) to a voltage source. Please connect OPAMP1 positive input channel (SJ4 port 3) to J2-9. Please connect OPAMP1 negative input channel (SJ5 port 3) to the GND.
Prepare the Demo
Connect a micro USB cable between the PC host and the MCU-Link USB port on the board
Open a serial terminal with the following settings (See Appendix A in Getting started guide for the description of how to determine serial port number):
115200 baud rate
8 data bits
No parity
One-stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
Opamp lpadc example. Please press any key to get opamp output value. opamp0OutputValue = 1644mv opamp1PositiveInputValue = 106mv Opamp1 output value measured by lpadc: 2703mv Opamp1 theoretical output value: 2704mv
Note: the OPAMP1 maximum output voltage is 3.1v, users need to pay attention to the input voltage value of the positive channel.
FRDM-MCXA366
Hardware requirements
Type-C USB cable
FRDM-MCXA366 board
Personal Computer
Board settings Please connect SJ1 to B type (2-3). Please connect OPAMP1 positive input channel (SJ4 port 3) to a voltage source. Please connect OPAMP1 positive input channel (SJ4 port 3) to J2-9. Please connect OPAMP1 negative input channel (SJ5 port 3) to the GND.
Prepare the Demo
Connect a micro USB cable between the PC host and the MCU-Link USB port on the board
Open a serial terminal with the following settings (See Appendix A in Getting started guide for the description of how to determine serial port number):
115200 baud rate
8 data bits
No parity
One-stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
Opamp lpadc example. Please press any key to get opamp output value. opamp0OutputValue = 1644mv opamp1PositiveInputValue = 106mv Opamp1 output value measured by lpadc: 2703mv Opamp1 theoretical output value: 2704mv
Note: the OPAMP1 maximum output voltage is 3.1v, users need to pay attention to the input voltage value of the positive channel.