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BCM2835/src/src/bcm2835.c  view on Meta::CPAN

        if( on )
            bcm2835_gpio_set_pud( pin, pud_compat_setting);
    }
    else
    {
    volatile uint32_t* paddr = bcm2835_gpio + BCM2835_GPPUDCLK0/4 + pin/32;
    uint8_t shift = pin % 32;
    bcm2835_peri_write(paddr, (on ? 1 : 0) << shift);
}
}

/* Read GPIO pad behaviour for groups of GPIOs */
uint32_t bcm2835_gpio_pad(uint8_t group)
{
  if (bcm2835_pads == MAP_FAILED)
    return 0;
  
    volatile uint32_t* paddr = bcm2835_pads + BCM2835_PADS_GPIO_0_27/4 + group;
    return bcm2835_peri_read(paddr);
}

/* Set GPIO pad behaviour for groups of GPIOs
// powerup value for all pads is
// BCM2835_PAD_SLEW_RATE_UNLIMITED | BCM2835_PAD_HYSTERESIS_ENABLED | BCM2835_PAD_DRIVE_8mA
*/
void bcm2835_gpio_set_pad(uint8_t group, uint32_t control)
{
  if (bcm2835_pads == MAP_FAILED)
    return;
  
    volatile uint32_t* paddr = bcm2835_pads + BCM2835_PADS_GPIO_0_27/4 + group;
    bcm2835_peri_write(paddr, control | BCM2835_PAD_PASSWRD);
}

/* Some convenient arduino-like functions
// milliseconds
*/
void bcm2835_delay(unsigned int millis)
{
    struct timespec sleeper;
    
    sleeper.tv_sec  = (time_t)(millis / 1000);
    sleeper.tv_nsec = (long)(millis % 1000) * 1000000;
    nanosleep(&sleeper, NULL);
}

/* microseconds */
void bcm2835_delayMicroseconds(uint64_t micros)
{
    struct timespec t1;
    uint64_t        start;
	
    if (debug)
    {
	/* Cant access sytem timers in debug mode */
	printf("bcm2835_delayMicroseconds %lld\n", (long long int) micros);
	return;
    }

    /* Calling nanosleep() takes at least 100-200 us, so use it for
    // long waits and use a busy wait on the System Timer for the rest.
    */
    start =  bcm2835_st_read();
   
    /* Not allowed to access timer registers (result is not as precise)*/
    if (start==0)
    {
	t1.tv_sec = 0;
	t1.tv_nsec = 1000 * (long)(micros);
	nanosleep(&t1, NULL);
	return;
    }

    if (micros > 450)
    {
	t1.tv_sec = 0;
	t1.tv_nsec = 1000 * (long)(micros - 200);
	nanosleep(&t1, NULL);
    }    
  
    bcm2835_st_delay(start, micros);
}

/*
// Higher level convenience functions
*/

/* Set the state of an output */
void bcm2835_gpio_write(uint8_t pin, uint8_t on)
{
    if (on)
	bcm2835_gpio_set(pin);
    else
	bcm2835_gpio_clr(pin);
}

/* Set the state of a all 32 outputs in the mask to on or off */
void bcm2835_gpio_write_multi(uint32_t mask, uint8_t on)
{
    if (on)
	bcm2835_gpio_set_multi(mask);
    else
	bcm2835_gpio_clr_multi(mask);
}

/* Set the state of a all 32 outputs in the mask to the values in value */
void bcm2835_gpio_write_mask(uint32_t value, uint32_t mask)
{
    bcm2835_gpio_set_multi(value & mask);
    bcm2835_gpio_clr_multi((~value) & mask);
}

/* Set the pullup/down resistor for a pin
//
// The GPIO Pull-up/down Clock Registers control the actuation of internal pull-downs on
// the respective GPIO pins. These registers must be used in conjunction with the GPPUD
// register to effect GPIO Pull-up/down changes. The following sequence of events is
// required:
// 1. Write to GPPUD to set the required control signal (i.e. Pull-up or Pull-Down or neither
// to remove the current Pull-up/down)
// 2. Wait 150 cycles ? this provides the required set-up time for the control signal

BCM2835/src/src/bcm2835.c  view on Meta::CPAN

    return data;
}  /* bcm2835_smi_read */
/* --------------------------------------------------- */

/* Read the System Timer Counter (64-bits) */
uint64_t bcm2835_st_read(void)
{
    volatile uint32_t* paddr;
    uint32_t hi, lo;
    uint64_t st;

    if (bcm2835_st==MAP_FAILED)
	return 0;

    paddr = bcm2835_st + BCM2835_ST_CHI/4;
    hi = bcm2835_peri_read(paddr);

    paddr = bcm2835_st + BCM2835_ST_CLO/4;
    lo = bcm2835_peri_read(paddr);
    
    paddr = bcm2835_st + BCM2835_ST_CHI/4;
    st = bcm2835_peri_read(paddr);
    
    /* Test for overflow */
    if (st == hi)
    {
        st <<= 32;
        st += lo;
    }
    else
    {
        st <<= 32;
        paddr = bcm2835_st + BCM2835_ST_CLO/4;
        st += bcm2835_peri_read(paddr);
    }
    return st;
}

/* Delays for the specified number of microseconds with offset */
void bcm2835_st_delay(uint64_t offset_micros, uint64_t micros)
{
    uint64_t compare = offset_micros + micros;

    while(bcm2835_st_read() < compare)
	;
}

/* PWM */

void bcm2835_pwm_set_clock(uint32_t divisor)
{
    if (   bcm2835_clk == MAP_FAILED
        || bcm2835_pwm == MAP_FAILED)
      return; /* bcm2835_init() failed or not root */
  
    /* From Gerts code */
    divisor &= 0xfff;
    /* Stop PWM clock */
    bcm2835_peri_write(bcm2835_clk + BCM2835_PWMCLK_CNTL, BCM2835_PWM_PASSWRD | 0x01);
    bcm2835_delay(110); /* Prevents clock going slow */
    /* Wait for the clock to be not busy */
    while ((bcm2835_peri_read(bcm2835_clk + BCM2835_PWMCLK_CNTL) & 0x80) != 0)
	bcm2835_delay(1); 
    /* set the clock divider and enable PWM clock */
    bcm2835_peri_write(bcm2835_clk + BCM2835_PWMCLK_DIV, BCM2835_PWM_PASSWRD | (divisor << 12));
    bcm2835_peri_write(bcm2835_clk + BCM2835_PWMCLK_CNTL, BCM2835_PWM_PASSWRD | 0x11); /* Source=osc and enable */
}

void bcm2835_pwm_set_mode(uint8_t channel, uint8_t markspace, uint8_t enabled)
{
  if (   bcm2835_clk == MAP_FAILED
       || bcm2835_pwm == MAP_FAILED)
    return; /* bcm2835_init() failed or not root */

  uint32_t control = bcm2835_peri_read(bcm2835_pwm + BCM2835_PWM_CONTROL);

  if (channel == 0)
    {
      if (markspace)
	control |= BCM2835_PWM0_MS_MODE;
      else
	control &= ~BCM2835_PWM0_MS_MODE;
      if (enabled)
	control |= BCM2835_PWM0_ENABLE;
      else
	control &= ~BCM2835_PWM0_ENABLE;
    }
  else if (channel == 1)
    {
      if (markspace)
	control |= BCM2835_PWM1_MS_MODE;
      else
	control &= ~BCM2835_PWM1_MS_MODE;
      if (enabled)
	control |= BCM2835_PWM1_ENABLE;
      else
	control &= ~BCM2835_PWM1_ENABLE;
    }

  /* If you use the barrier here, wierd things happen, and the commands dont work */
  bcm2835_peri_write_nb(bcm2835_pwm + BCM2835_PWM_CONTROL, control);
  /*  bcm2835_peri_write_nb(bcm2835_pwm + BCM2835_PWM_CONTROL, BCM2835_PWM0_ENABLE | BCM2835_PWM1_ENABLE | BCM2835_PWM0_MS_MODE | BCM2835_PWM1_MS_MODE); */

}

void bcm2835_pwm_set_range(uint8_t channel, uint32_t range)
{
  if (   bcm2835_clk == MAP_FAILED
       || bcm2835_pwm == MAP_FAILED)
    return; /* bcm2835_init() failed or not root */

  if (channel == 0)
      bcm2835_peri_write_nb(bcm2835_pwm + BCM2835_PWM0_RANGE, range);
  else if (channel == 1)
      bcm2835_peri_write_nb(bcm2835_pwm + BCM2835_PWM1_RANGE, range);
}

void bcm2835_pwm_set_data(uint8_t channel, uint32_t data)
{
  if (   bcm2835_clk == MAP_FAILED
       || bcm2835_pwm == MAP_FAILED)