54 lines
1.9 KiB
Plaintext
54 lines
1.9 KiB
Plaintext
Overview
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========
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The CMP polling Example shows the simplest way to use CMP driver and help user with a quick start.
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In this example, user should indicate an input channel to capture a voltage signal (can be controlled by user) as the
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CMP's positive channel input. On the negative side, the internal VREF ladder is used to generate the fixed voltage about
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half value of reference voltage.
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When running the project, change the input voltage of user-defined channel, then the comparator's output would change
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between logic one and zero when the user's voltage crosses the internal VREF's value. The endless loop in main() function
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would detect the logic value of comparator's output, and change the LED. The LED would be turned on when the compare
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output is logic one, or turned off when zero.
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Toolchain supported
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===================
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- IAR embedded Workbench 9.20.2
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- Keil MDK 5.36
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- GCC ARM Embedded 10.3.1
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- MCUXpresso 11.5.0
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Hardware requirements
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=====================
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- Mini/micro USB cable
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- LPCxpresso55s69 board
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- Personal Computer
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Board settings
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==============
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Connect a DC voltage source to P19_6 (PIO0_0/CMP IN1)
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Prepare the Demo
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================
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Note: MCUXpresso IDE project default debug console is semihost
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1. Connect a micro USB cable between the PC host and the OpenSDA USB port on the board.
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2. Open a serial terminal on PC for OpenSDA serial device with these settings:
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- 115200 baud rate
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- 8 data bits
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- No parity
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- One stop bit
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- No flow control
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3. Download the program to the target board.
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4. Reset the SoC and run the project.
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Running the demo
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================
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When the demo runs successfully, the log would be seen on the OpenSDA terminal like:
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CMP polling driver example
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Then change CMP analog input, and the LED GREEN will show the output of the comparator.
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- Let CMP IN1 voltage be higher than half of the VDDA, LED GREEN on.
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- Let CMP IN1 voltage be lower than half of the VDDA, LED GREEN off.
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