Accelerometer Interface (ADXL345)

Files
file	acc-adxl345.c
	ADXL345 Accelerometer interface implementation
file	acc-adxl345.h
	ADXL345 Accelerometer interface definitions

Macros
#define	ADXL345_CS   2
#define	ADXL345_DATA_FORMAT_REG   0x31
#define	ADXL345_DATA_FORMAT_DATA   0x00
#define	ADXL345_POWER_CTL_REG   0x2D
#define	ADXL345_POWER_CTL_DATA   0x08
#define	ADXL345_BW_RATE_REG   0x2C
#define	ADXL345_BW_RATE_DATA   0x0A

Functions
int8_t	adxl345_init (void)
	Initialize the ADXL345 Acceleration Sensor. More...
uint16_t	adxl345_get_x_acceleration (void)
	This function returns the current measured acceleration at the x-axis of the adxl345. More...
uint16_t	adxl345_get_y_acceleration (void)
	This function returns the current measured acceleration at the y-axis of the adxl345. More...
uint16_t	adxl345_get_z_acceleration (void)
	This function returns the current measured acceleration at the z-axis of the adxl345. More...
acc_data_t	adxl345_get_acceleration (void)
	This function returns the current measured acceleration of all axis (x,y,z) More...
void	adxl345_write (uint8_t reg, uint8_t data)
	This function writes data to the given register of the ADXL345. More...
uint8_t	adxl345_read (uint8_t reg)
	This function reads from the given register of the ADXL345. More...

Detailed Description

In previous Projects we evaluated some accelerometer sensors and the digital ADXL345 is the best choice for an sensor node application. All accelerometers have nearly the same performance characteristics, but he ADXL345 is very cheap and has the lowest power consumption.

Macro Definition Documentation

#define ADXL345_BW_RATE_DATA   0x0A

ADXL Data Rate and Power Mode Control Register Data:

D7	D6	D5	D4	D3	D2	D1	D0
0	0	0	LOW_POWER	Rate_3	Rate_2	Rate_1	Rate_0

Note

For further information use the ADXL345 Datasheet

Default value: 0x0A

Definition at line 192 of file acc-adxl345.h.

Referenced by adxl345_init().

#define ADXL345_BW_RATE_REG   0x2C

ADXL Data Rate and Power Mode Control Register

Definition at line 164 of file acc-adxl345.h.

Referenced by adxl345_init().

#define ADXL345_CS   2

SPI device order. The chip select number where the ADXL345 is connected to the BCD-decimal decoder

Definition at line 93 of file acc-adxl345.h.

Referenced by adxl345_init(), adxl345_read(), and adxl345_write().

#define ADXL345_DATA_FORMAT_DATA   0x00

ADXL Data Format Register Data:

D7	D6	D5	D4	D3	D2	D1	D0
SELF_TEST	SPI	INT_INVERT	0	FULL_RES	Justify	Range	Range

Note

For further information use the ADXL345 Datasheet

Default value: 0x00

Definition at line 126 of file acc-adxl345.h.

Referenced by adxl345_init().

#define ADXL345_DATA_FORMAT_REG   0x31

ADXL Data Format Register

Definition at line 98 of file acc-adxl345.h.

Referenced by adxl345_init().

#define ADXL345_POWER_CTL_DATA   0x08

ADXL Power Control Register Data:

D7	D6	D5	D4	D3	D2	D1	D0
0	0	Link	Auto Sleep	Measure	Sleep	Wakeup	Wakeup

Note

For further information use the ADXL345 Datasheet

Default value: 0x00

Definition at line 159 of file acc-adxl345.h.

Referenced by adxl345_init().

#define ADXL345_POWER_CTL_REG   0x2D

ADXL Power Control Register

Definition at line 131 of file acc-adxl345.h.

Referenced by adxl345_init().

Function Documentation

acc_data_t adxl345_get_acceleration

(

void

)

This function returns the current measured acceleration of all axis (x,y,z)

Returns

current acceleration value of all axis

Definition at line 85 of file acc-adxl345.c.

References adxl345_get_x_acceleration(), adxl345_get_y_acceleration(), and adxl345_get_z_acceleration().

uint16_t adxl345_get_x_acceleration

(

void

)

This function returns the current measured acceleration at the x-axis of the adxl345.

Returns

current x-axis acceleration value

Definition at line 60 of file acc-adxl345.c.

References adxl345_read().

Referenced by adxl345_get_acceleration().

uint16_t adxl345_get_y_acceleration

(

void

)

This function returns the current measured acceleration at the y-axis of the adxl345.

Returns

current y-axis acceleration value

Definition at line 69 of file acc-adxl345.c.

References adxl345_read().

Referenced by adxl345_get_acceleration().

uint16_t adxl345_get_z_acceleration

(

void

)

This function returns the current measured acceleration at the z-axis of the adxl345.

Returns

current z-axis acceleration value

Definition at line 77 of file acc-adxl345.c.

References adxl345_read().

Referenced by adxl345_get_acceleration().

int8_t adxl345_init

(

void

)

Initialize the ADXL345 Acceleration Sensor.

The specific sensor settings are provided by

• ADXL345_DATA_FORMAT_DATA
• ADXL345_POWER_CTL_DATA
• ADXL345_BW_RATE_DATA

Returns

• 0 ADXL345 available
• -1 ADXL345 not available

Definition at line 41 of file acc-adxl345.c.

References ADXL345_BW_RATE_DATA, ADXL345_BW_RATE_REG, ADXL345_CS, ADXL345_DATA_FORMAT_DATA, ADXL345_DATA_FORMAT_REG, ADXL345_POWER_CTL_DATA, ADXL345_POWER_CTL_REG, adxl345_read(), adxl345_write(), MSPI_BAUD_MAX, mspi_chip_release(), mspi_init(), and MSPI_MODE_3.

uint8_t adxl345_read

(

uint8_t

reg

)

This function reads from the given register of the ADXL345.

Parameters

reg	The register address

Returns

The data value

Definition at line 101 of file acc-adxl345.c.

References ADXL345_CS, mspi_chip_release(), mspi_chip_select(), and mspi_transceive().

Referenced by adxl345_get_x_acceleration(), adxl345_get_y_acceleration(), adxl345_get_z_acceleration(), and adxl345_init().

void adxl345_write	(	uint8_t	reg,
		uint8_t	data
	)

This function writes data to the given register of the ADXL345.

Parameters

reg	The register address
data	The data value

Definition at line 93 of file acc-adxl345.c.

References ADXL345_CS, mspi_chip_release(), mspi_chip_select(), and mspi_transceive().

Referenced by adxl345_init().