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#include "altimeter.hpp"
#include "hardware/gpio.h"
altimeter::altimeter(i2c_inst_t* inst, uint8_t addr) {
this->inst = inst;
this->addr = addr;
}
void altimeter::initialize() {
// Select control register(0x26)
// Active mode, OSR = 16, altimeter mode(0xB8)
this->buffer[0] = 0x26;
this->buffer[1] = 0x89;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
}
void altimeter::initialize(float threshold_altitude, uint8_t interrupt_pin, gpio_irq_callback_t callback) {
this->initialize();
// Below configures the interrupt for the first transition from PAD to BOOST
// Initial Reading
sleep_ms(1000);
float altitude = 0.0f;
while (altitude == 0.0f) {
altitude = this->get_altitude_converted();
}
threshold_altitude += altitude; // 30 meters above ground
// Select control register 3 (0x28)
// Set bot interrupt pins to active low and enable internal pullups
this->buffer[0] = 0x28;
this->buffer[1] = 0x01;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select pressure target MSB register(0x16)
// Set altitude target to 30 meters above ground altitude
this->buffer[0] = 0x16;
this->buffer[1] = (uint8_t) (((int16_t)(threshold_altitude)) >> 8);
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select pressure target LSB register(0x17)
// Set altitude target to 30 meters above ground altitude
this->buffer[0] = 0x17;
this->buffer[1] = (uint8_t) (((int16_t)(threshold_altitude)));
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select interrupt enable register (0x29)
// Set interrupt enabled for altitude threshold(0x08)
this->buffer[0] = 0x29;
this->buffer[1] = 0x08;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select interrupt this->bufferuration register (0x2A)
// Set interrupt enabled for altitude threshold to route to INT1 pin(0x08)
this->buffer[0] = 0x2A;
this->buffer[1] = 0x08;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
gpio_set_irq_enabled_with_callback(interrupt_pin, GPIO_IRQ_LEVEL_LOW, true, callback);
// End of configuration of interrupt for first transition from PAD to BOOST
}
void altimeter::set_threshold_altitude(float threshold_altitude, uint8_t interrupt_pin, gpio_irq_callback_t callback) {
float altitude = 0.0f;
while (altitude == 0.0f) {
altitude = get_altitude_converted();
}
threshold_altitude += altitude;
// Select control register 3 (0x28)
// Set bot interrupt pins to active low and enable internal pullups
this->buffer[0] = 0x28;
this->buffer[1] = 0x01;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select pressure target MSB register(0x16)
// Set altitude target to 30 meters above ground altitude
this->buffer[0] = 0x16;
this->buffer[1] = (uint8_t) (((int16_t)(threshold_altitude)) >> 8);
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select pressure target LSB register(0x17)
// Set altitude target to provided threshold altitude
this->buffer[0] = 0x17;
this->buffer[1] = (uint8_t) (((int16_t)(threshold_altitude)));
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select interrupt enable register (0x29)
// Set interrupt enabled for altitude threshold(0x08)
this->buffer[0] = 0x29;
this->buffer[1] = 0x08;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select interrupt this->bufferuration register (0x2A)
// Set interrupt enabled for altitude threshold to route to INT1 pin(0x08)
this->buffer[0] = 0x2A;
this->buffer[1] = 0x08;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
gpio_set_irq_enabled_with_callback(interrupt_pin, GPIO_IRQ_LEVEL_LOW, true, callback);
// End of configuration of interrupt for first transition from PAD to BOOST
}
void altimeter::unset_threshold_altitude(uint8_t interrupt_pin) {
gpio_set_irq_enabled_with_callback(interrupt_pin, GPIO_IRQ_LEVEL_LOW, false, NULL);
// Select interrupt enable register (0x29)
// Set interrupt enabled for altitude threshold(0x08)
this->buffer[0] = 0x29;
this->buffer[1] = 0x00;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
// Select interrupt configuration register (0x2A)
// Set interrupt enabled for altitude threshold to route to INT1 pin(0x08)
this->buffer[0] = 0x2A;
this->buffer[1] = 0x00;
i2c_write_blocking(this->inst, this->addr, this->buffer, 2, true);
}
float altimeter::get_altitude_converted() {
uint8_t reg = 0x01;
i2c_write_blocking(this->inst, this->addr, ®, 1, true);
i2c_read_blocking(this->inst, this->addr, this->altitude_buffer, 4, false);
// Exactly how MPL3115A2 datasheet says to retrieve altitude
float altitude = (float) ((int16_t) ((this->altitude_buffer[0] << 8) | this->altitude_buffer[1])) + (float) (this->altitude_buffer[2] >> 4) * 0.0625;
return altitude;
}
void altimeter::get_altitude_raw(uint8_t* buffer) {
uint8_t reg = 0x01;
i2c_write_blocking(this->inst, this->addr, ®, 1, true);
i2c_read_blocking(this->inst, this->addr, buffer, 3, false);
}
uint32_t altimeter::expose_buffer(uint8_t** buffer) {
*buffer = this->altitude_buffer;
return sizeof(this->altitude_buffer);
}
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