mag_micromag_fw_hw.h

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#ifndef MICROMAG_FW_HW_H
#define MICROMAG_FW_HW_H

#include <stdlib.h>  // for abs

#include "std.h"
#include "LPC21xx.h"
#include "mcu.h"

#include "mcu_periph/spi.h"
#include BOARD_CONFIG

#include "generated/airframe.h"

#define MM_DIVISOR_128  2
#define MM_DIVISOR_256  3
#define MM_DIVISOR_512  4
#define MM_DIVISOR_1024 5

#define MM_DIVISOR MM_DIVISOR_512


extern volatile uint8_t micromag_cur_axe;

#define MmSelect() SetBit(MM_SS_IOCLR,MM_SS_PIN)
#define MmUnselect() SetBit(MM_SS_IOSET,MM_SS_PIN)

#define MmReset() SetBit(MM_RESET_IOCLR,MM_RESET_PIN)
#define MmSet() SetBit(MM_RESET_IOSET,MM_RESET_PIN)

#define MmOnSpiIt() {                                       \
    switch (micromag_status) {                              \
      case MM_SENDING_REQ:                                  \
      {                                                   \
        /* read dummy control byte reply */       \
        uint8_t foo __attribute__ ((unused)) = SSPDR;     \
        micromag_status = MM_WAITING_EOC;                 \
        MmUnselect();                                     \
        SpiClearRti();                                    \
        SpiDisableRti();                                  \
        SpiDisable();                                     \
      }                                                   \
      break;                                              \
      case MM_READING_RES:                                  \
      {                                                   \
        int16_t new_val;                                  \
        new_val = SSPDR << 8;                             \
        new_val += SSPDR;                                 \
        if (abs(new_val) < 2000)                          \
          micromag_values[micromag_cur_axe] = new_val;    \
        MmUnselect();                                     \
        SpiClearRti();                                    \
        SpiDisableRti();                                  \
        SpiDisable();                                     \
        micromag_cur_axe++;                               \
        if (micromag_cur_axe > 2) {                       \
          micromag_cur_axe = 0;                           \
          micromag_status = MM_DATA_AVAILABLE;            \
        }                                                 \
        else                                              \
          micromag_status = MM_IDLE;                      \
      }                                                   \
      break;                                              \
    }                                                       \
  }


#define MmSendReq() {                                                   \
    MmSelect();                                                         \
    micromag_status = MM_SENDING_REQ;                                   \
    MmSet();                                                            \
    SpiClearRti();                                                      \
    SpiEnableRti();                                                     \
    MmReset();                                                          \
    uint8_t control_byte = (micromag_cur_axe+1) << 0 | MM_DIVISOR_1024 << 4; \
    SSPDR = control_byte;                                               \
    SpiEnable();                                                        \
  }

#define MmReadRes() {             \
    micromag_status = MM_READING_RES;           \
    MmSelect();                                 \
    /* trigger 2 bytes read */                  \
    SSPDR = 0;                                  \
    SSPDR = 0;                                  \
    SpiEnable();                                \
    SpiClearRti();                              \
    SpiEnableRti();                             \
  }

extern void micromag_hw_init(void);

#endif /* MICROMAG_HW_H */