Eddy Current Sensor Driver

This driver is used to control and configure the AMDC Eddy Current Sensor IP core in the FPGA through the AXI4-Lite interface.

Files

All files for the eddy current sensor driver are in the AMDC-Firmware driver directory (sdk/app_cpu1/common/drv/).

drv/
|-- eddy_current_sensor.c
|-- eddy_current_sensor.h

Connecting and Enabling

The eddy current sensor adapter board should be connected to one of the GPIO ports on the AMDC with a DB-15 cable. Additionally, the firmware driver must be routed to the connected port via the GPIO Mux (AMDC REV D) or GP3IO Mux (AMDC REV E). See the documentation on the GPIO muxes here.

As of AMDC Firmware release v1.3, sensors must also be enabled in the Timing Manager as follows, to be triggered for periodic data sampling:

void timing_manager_enable_sensor(sensor_e sensor)

This function enables a sensor in the timing manager for period data sampling. To enable an eddy current sensor for a given GPIO port N, “EDDY_N” should passed in as the argument for sensor.

Driving the Eddy Current Sensor

void eddy_current_sensor_init(void)

This function is called by the BSP and initializes all eddy_current_sensor IP to use the default timing parameters (SCLK frequency and propogation delay).

void eddy_current_sensor_set_timing(uint32_t base_addr, uint32_t sclk_freq_khz, uint32_t propogation_delay_ns)

This function can be used to override the default timing parameters for a given eddy current sensor instance.

double eddy_current_sensor_read_x_voltage(uint32_t base_addr)

This function reads the X data from the IP data register. The returned data is sign extended 2’s compliment 18-bit data.

double eddy_current_sensor_read_y_voltage(uint32_t base_addr)

This function reads the Y data from the IP data register. The returned data is sign extended 2’s compliment 18-bit data.

Example Code

///////////////////////////////////
//  In app_controller.c  
///////////////////////////////////

#include "drv/timing_manager.h"

// Other includes and app functions...

void app_controller_init() 
{
  // Set GPIO port 1 on AMDC to eddy current sensor
#if (USER_CONFIG_HARDWARE_TARGET == AMDC_REV_D)
  gpio_mux_set_device(0, 1);
#elif (USER_CONFIG_HARDWARE_TARGET == AMDC_REV_E ) || (USER_CONFIG_HARDWARE_TARGET == AMDC_REV_F)
  gp3io_mux_set_device(GP3IO_MUX_1_BASE_ADDR, 2);
#endif

  // Enable eddy current sensor in timing manager
  timing_manager_enable_sensor(EDDY_1);

  // More Initialization code...

  return;
}

///////////////////////////////////
//  In task_controller.c   
//////////////////////////////////

#include "drv/encoder.h"

// Other includes and functions...

void task_controller_callback(void *arg)
{
  // Other callback code...

  // Read X and Y positional data as voltage
  double voltage_x = eddy_current_sensor_read_x_voltage(EDDY_CURRENT_SENSOR_1_BASE_ADDR);
  double voltage_y = eddy_current_sensor_read_y_voltage(EDDY_CURRENT_SENSOR_1_BASE_ADDR);


  // Use the positional data
  my_bearing_control_function(voltage_x, voltage_y);

  return;
}