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.
Diff: as5048spi.h
- Revision:
- 0:3edcf58e51e7
- Child:
- 2:2958500883e0
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/as5048spi.h Thu Sep 18 10:20:22 2014 +0000 @@ -0,0 +1,49 @@ +#include "mbed.h" +typedef enum { + AS_FLAG_PARITY = 0x8000, + AS_FLAG_READ = 0x4000, +} As5048Flag; + +typedef enum { + AS_CMD_NOP = 0x0000, + AS_CMD_ERROR = 0x0001 | AS_FLAG_READ, // Reads error ireguster and clear error flags + AS_CMD_DIAGNOSTICS = 0x3FFD | AS_FLAG_READ, // Reads automatic gain control and diagnostics info + AS_CMD_MAGNITUDE = 0x3FFE | AS_FLAG_READ, + + AS_CMD_ANGLE = 0x3FFF| AS_FLAG_PARITY | AS_FLAG_READ, +} As5048Command; + + + +class As5048Spi +{ +public: + As5048Spi(PinName mosi, PinName miso, PinName sclk, PinName chipselect, int nDevices = 1); + ~As5048Spi(); + + bool error(int device = -1); + void frequency(int frequency = 1000000); + const int* read(As5048Command command); + const int* read_sequential(As5048Command command); + + const int* read_angle(); + const int* read_angle_sequential(); + + + static int mask(int sensor_result); + + static bool parity_check(int sensor_result); + static int degrees(int sensor_result); + static int radian(int sensor_result); + + +protected: + int _nDevices; + DigitalOut _chipSelectN; + SPI _spi; + + int* _readBuffer; // Stores the results of the last sequential read + + int* _read(As5048Command command); +}; + \ No newline at end of file