Introduction
This example uses the EQEP to measure frequency of a signal generated by ePWM.
The example does the below
- Configures EPWM to generate a signal and EQEP to measure frequency of this generated signal (a loopback connection is required).
- The application runs for the specified time and the frequency calculation is done using the EPWM ISR.
- After the specified time, the application checks if the measured frequency was within range of the generated frequency.
AM62LX-EVM
- This example uses the user expansion connector (J2) in the board for testing on AM62LX-SK.
- All pin numbers are on the expansion connector in the board.
- The pins configured for the example is enabled on user expansion connector based on the FET selection switch(FET_SEL0).
- The SOC_VOUT0_DATAn are the input to FET switches. The pins that are configured for the example are pinmuxed with the FET switches.
- The S0 select pin decides if the configured pins (which is pinmuxed with SOC_VOUT0_DATAn) map to HDMI or USER EXP connector.
- The S0 pin is triggered to a high value in the software. When the S0 is high, the pin that is configured for the example (which is pinmuxed with SOC_VOUT0_DATAn) will be available on the user expansion connector.
The below diagram depicts the selection:
S2 | S1 | S0 | IP(nA)/OP(nB1 (Or) nB2) |
H | H | L | nA=nB1 -> SOC - HDMI |
H | H | H | nA=nB2 -> SOC - GPIO EXP CONN |
Below is the connection details.
- Connect EPWM0A to EQEP0A (EPWM simulates EQEP signal)
- Connect J2 Pin 18 (EPWM0A) to J2 Pin 19 (EQEP0A)
Supported Combinations
Parameter | Value |
CPU + OS | a53ss0-0 nortos |
a53ss0-0 freertos |
Toolchain | arm.gnu.aarch64-none |
Board | am62lx-evm |
Example folder | examples/drivers/eqep/eqep_frequency_measurement/ |
Steps to Run the Example
- When using CCS projects to build, import the CCS project for the required combination and build it using the CCS project menu (see Using SDK with CCS Projects).
- When using makefiles to build, note the required combination and build using make command (see Using SDK with Makefiles)
- Establish connections as mentioned in External Connections section
- To Load and Run an example (see Application Run and debugging using CCS)
- View the UART console logs for results
See Also
EQEP
Sample Output
Shown below is a sample output when the application is run,
EQEP Frequency Measurement Test Started ...
Please ensure EPWM to EQEP loopback is connected...
Please wait 10 seconds ...
Expected frequency = 10000 Hz, Measured frequency = 10000 Hz
EQEP Frequency Measurement Test Passed!!
All tests have passed!!