Saxion Lectoraat MT / AS5048

AS5048A SPI - Magnetic rotary encoder library

Library for communication over the SPI interface with the ams.com AS5048A magnetic rotary encoder.

Example:

Simple readout of a single angle measurement from a single sensor on the SPI-bus

#include "mbed.h"
#include <as5048spi.h>

// The sensors connection are attached to pins 5-8
As5048Spi sensor(p5, p6, p7, p8);
Serial pc(USBTX, USBRX); // tx, rx

int main() {
    while(1) {
        // 
        const int* angles = sensor.read_angle();
        int angle = angles[0];
        
        // The read angle returns the value returned over the SPI bus, including parity bit
        pc.printf("Read result: %x\r\n", angle);
        
        if( As5048Spi::parity_check(angle) )
        {
            // Convert range from 0 to 2^14-1 to 0 - 360 degrees
            int degrees = As5048Spi::degrees(angle)/100;
            pc.printf("Parity check succesfull.\r\n");
            pc.printf("Angle: %i degrees\r\n", degrees );
        }
        else
        {
            pc.printf("Parity check failed.\r\n");
        }
            
        wait_ms(500);
    }
}

The class supports daisy chaining multiple sensors on the SPI-bus as well. See: SPI-Daisy-Chaining.

Files at this revision

API Documentation at this revision

Revision 4:06b89a41109e, committed 2015-03-17

Comitter:
JSpikker
Date:
Tue Mar 17 14:56:30 2015 +0000
Parent:
3:a8ad32e439d4
Commit message:
Fixed documentation.

Changed in this revision

as5048spi.h Show annotated file Show diff for this revision Revisions of this file 
--- a/as5048spi.h	Tue Mar 17 14:46:45 2015 +0000
+++ b/as5048spi.h	Tue Mar 17 14:56:30 2015 +0000
@@ -21,7 +21,7 @@
 } As5048Diagnostics;
 
 
-
+//! Class for interfacing with the AMS AS5048A magnetic rotary sensor over the SPI-interface.
 class As5048Spi
 {
 public:
@@ -46,7 +46,6 @@
     /// Performs a single angle measurement on all sensors
     /// @return Array of raw angle data. To get the 14-bit value representing
     ///     the angle, apply the mask() to the result.
-    ///     To get an angle in degrees divide 360 by the result of the call to mask().
     const int* read_angle();
     
     /// Performs sequential angle measurements on all sensors. The first time this
@@ -54,7 +53,6 @@
     /// will be returned by the next call to this method.
     /// @return Array of raw angle data. To get the 14-bit value representing
     ///     the angle, apply the mask() to the result.
-    ///     To get an angle in degrees divide 360 by the result of the call to mask().
     const int* read_angle_sequential();
 
     /// Returns lowest 14-bits
@@ -62,6 +60,7 @@
 
     /// Applies the mask to the first n bytes in the read buffer (for daisychained sensors).
     static void mask(int* sensor_results, int n);
+    
     /// Checks if the return value from the sensor has the right parity
     /// @return true if ok
     static bool parity_check(int sensor_result);