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Multiple Axis : Program, Circuit and Remaining tasks

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Naveen Saini edited this page Aug 30, 2017 · 4 revisions

Sampling Principle:

Since the ADC in PRU-DAQ, AD9201, can sample only two inputs simultaneously, a analog switch is used to switch the input channels, so that more than two channels can be sampled.By this method, PRu-DAQ is made to sample 8 channels, so in this program we are going to use PRU0 for switching the input channels and PRU1 for reading the data from ADC and transfer sampled data to BBB host system, however during the reading and transferring , it downsamples the data. Following diagram illustrates the data flow. Data Flow

Circuit:

Following circuit uses pwm output directly, however I feel that some other device like capacitor or something else could be used to improve the efficiency and distortions in connections.Also make suitable changes to this circuit before trying it. temporary circuit

Remaining Tasks:

  • I can't get SIG_Handler work in C program, so the program does not exit normally with Ctrl+C
  • The clock rate is to be decided by PRU0, currently the rate is default that I got from prudaq repository, it can be modified with the new assembly program for PRU0
  • Design Circuit: to trigger the sensor from pwm_output, but since the pwm_output cannot be directly interfaced with sensor, we have to change voltage level according to sensor specs.
  • amplify the receiver output
  • Configure the sampling rate and interval for result output
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