pwm.h

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#ifndef PWM_H_
#define PWM_H_

#include <errno.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>

#include "log.h"
#include "types.h"

// base addresses
#define PWMSS0_BASE 0x48300000
#define PWMSS1_BASE 0x48302000
#define EPWM_OFFSET 0x0200

// pwm size
#define PWM_SIZE 0x00000FFF

// configuration registers
#define TBCTL (EPWM_OFFSET + 0x0) / sizeof(uint16_t) // counter control
#define TBPRD (EPWM_OFFSET + 0xA) / sizeof(uint16_t) // period
#define CMPA (EPWM_OFFSET + 0x12) / sizeof(uint16_t) // compare
#define CMPB (EPWM_OFFSET + 0x14) / sizeof(uint16_t)
#define AQCTLA (EPWM_OFFSET + 0x16) / sizeof(uint16_t) // action qualifier
#define AQCTLB (EPWM_OFFSET + 0x18) / sizeof(uint16_t)

// register values
#define TBCTL_DEFAULT 0xC000
#define UP_DOWN_COUNT 0x0002
#define PRESCALE2 0x0400

// range switch clock configuration (action qualifier)
#define RWC_AQ_A 0x0060 // set when incrementing, clear when decrementing
#define RWC_AQ_B 0x0900 // set when decrementing, clear when incrementing

// pulse configuration
#define PULSE_WIDTH 0.1 // 10% of sampling period
#define MARGIN 0.1
#define PWM_PERIOD_SCALE                                                       \
    50000000 *                                                                 \
        (1 + PULSE_WIDTH + MARGIN) // period scaling factor (period is set in
                                   // 5ns, (/2 clock prescaling))

// ADC clock settings
#define ADC_CLOCK_PERIOD 48 // in 10ns
#define ADC_AQ 0x0025 // clear on zero and period, set at 50%

int pwm_setup(void);
void pwm_close(void);

void pwm_setup_range_clock(int sample_rate);
void pwm_setup_adc_clock(void);

#endif /* PWM_H_ */