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Lab 8: Servicing the ADC with DMA

TMS320F2837xD Microcontroller Workshop - Direct Memory Access 8 - 17

7. Modify the end of Dma.c to do the following:

- Enable the “DMA_CH1” interrupt in the PIE (Hint: use the PieCtrlRegs structure)

- Enable the appropriate core interrupt in the IER register

8. Open and inspect DefaultIsr_8.c. Notice that this file contains the DMA interrupt

service routine. Save all modified files.

Build and Load

9. Click the “Build” button and watch the tools run in the Console window. Check for

errors in the Problems window.

10. Click the “Debug” button (green bug). A Launching Debug Session window will open.

Select only CPU1 to load the program on (i.e. uncheck CPU2), and then click OK. Then

the CCS Debug perspective view should open, the program will load automatically, and

you should now be at the start of main(). If the device has been power cycled since the

last lab exercise, be sure to configure the boot mode to EMU_BOOT_SARAM using the

Scripts menu.

Run the Code – Test the DMA Operation

Note: For the next step, check to be sure that the jumper wire connecting PWM1A (header J4,

pin #40) to ADCINA0 (header J3, pin #30) is in place on the LaunchPad.

11. Run the code in real-time mode using the Script function: Scripts  Realtime

Emulation Control  Run_Realtime_with_Reset. Open and watch the

memory browser update. Verify that the ADC result buffer contains updated values.

12. Open and setup a graph to plot a 50-point window of the ADC results buffer.

Click: Tools  Graph  Single Time and set the following values:

Acquisition Buffer Size 50

DSP Data Type 16-bit unsigned integer

Sampling Rate (Hz) 50000

Start Address AdcBuf

Display Data Size 50

Time Display Unit

µs

Select OK to save the graph options.

13. The graphical display should show the generated 2 kHz, 25% duty cycle symmetric PWM

waveform. Notice that the results match the previous lab exercise.

14. Fully halt the CPU (real-time mode) by using the Script function: Scripts 

Realtime Emulation Control  Full_Halt.

Texas Instruments TMS320F2837 D Series Workshop Guide And Lab Manual

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