sensor_bus.h File Reference

Sensor API Platform Bus Interfaces.

Copyright (c) 2011-2018 Microchip Technology Inc. and its subsidiaries.

#include <status_codes.h>

Data Structures
struct	bus_desc_t
	Platform Bus Interface Descriptor. More...

Typedefs
typedef status_code_t	bus_status_t
	Platform Bus Status Constants. More...
typedef SPI_t *	spi_if

Enumerations
enum	bus_type_t {   BUS_TYPE_UNKNOWN,   BUS_TYPE_TWI,   BUS_TYPE_SPI,   BUS_TYPE_PMBUS,   BUS_TYPE_SMBUS }
	Platform Bus Type Constants. More...

Functions
System Bus I/O Access Methods
bool	bus_init (volatile void *busif, uint32_t speed)
size_t	bus_read (bus_desc_t *bus, uint8_t addr, void *data, size_t count)
	Read multiple Bytes from a bus interface. More...
size_t	bus_write (bus_desc_t *bus, uint8_t addr, const void *data, size_t count)
	Write multiple Bytes to a bus interface. More...
bool	bus_probe (bus_desc_t *bus, int arg)
	Determine the existence of a bus device. More...
static uint8_t	bus_get (bus_desc_t *bus, uint8_t addr)
	Read a single Byte from a bus interface. More...
static void	bus_put (bus_desc_t *bus, uint8_t addr, uint8_t data)
	Write a single Byte to a bus interface. More...
static void	bus_reg_bitclear (bus_desc_t *bus, uint8_t addr, uint8_t mask)
	Clear a bit at a bus device register or memory address. More...
static void	bus_reg_bitset (bus_desc_t *bus, uint8_t addr, uint8_t mask)
	Set a bit at a bus device register or memory address. More...
uint8_t	bus_reg_fieldget (bus_desc_t *bus, uint8_t addr, uint8_t mask)
	Read a field stored at a device register or memory address. More...
void	bus_reg_fieldset (bus_desc_t *bus, uint8_t addr, uint8_t mask, uint8_t value)
	Write a field stored at a device register or memory address. More...

typedef status_code_t bus_status_t

Platform Bus Status Constants.

typedef SPI_t* spi_if

Platform Bus Interface Types

enum bus_type_t

Platform Bus Type Constants.

Enumerator
BUS_TYPE_UNKNOWN	Unknown bus.
BUS_TYPE_TWI	TWI/I2C bus.
BUS_TYPE_SPI	SPI bus.
BUS_TYPE_PMBUS	PMBus protocol.
BUS_TYPE_SMBUS	SMBus protocol.

static uint8_t bus_get ( bus_desc_t *  bus, uint8_t  addr  )

inlinestatic

Read a single Byte from a bus interface.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.

Returns

A value fetched from the device. This value is undefined in the event of an I/O error.

References bus_read(), and data.

Referenced by bus_reg_bitclear(), bus_reg_bitset(), bus_reg_fieldget(), and bus_reg_fieldset().

bool bus_init	(	volatile void *	busif,
		uint32_t	speed
	)

Initialize the bus I/O interface.

Parameters

busif	The address of a system bus (registers) interface.
speed	The bus data rate.

Return values

true	The bus was initialized.
false	The bus was not initialized.

bool bus_probe	(	bus_desc_t *	bus,
		int	arg
	)

Determine the existence of a bus device.

This routine determines the existence of a device located at a bus interface and address specified by an initialized bus descriptor. Implementations are only required to return true when it can be determined that a device is installed at the bus interface address.

Parameters

bus	An initialized bus interface descriptor.
arg	Ignored reserved argument.

Return values

true	A device responded to the bus address.
false	A device did not respond to the bus address.

static void bus_put ( bus_desc_t *  bus, uint8_t  addr, uint8_t  data  )

inlinestatic

Write a single Byte to a bus interface.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
data	The value of the Byte to write.

Returns

Nothing

References bus_write().

Referenced by bus_reg_bitclear(), bus_reg_bitset(), and bus_reg_fieldset().

size_t bus_read	(	bus_desc_t *	bus,
		uint8_t	addr,
		void *	data,
		size_t	count
	)

Read multiple Bytes from a bus interface.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
data	The destination read buffer address.
count	The destination read buffer size (Bytes).

Returns

The number of Bytes read, which may be less than the requested number of Bytes in the event of an error.

Referenced by bus_get().

static void bus_reg_bitclear ( bus_desc_t *  bus, uint8_t  addr, uint8_t  mask  )

inlinestatic

Clear a bit at a bus device register or memory address.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
mask	The mask value of the bit to clear.

Returns

Nothing

References bus_get(), and bus_put().

static void bus_reg_bitset ( bus_desc_t *  bus, uint8_t  addr, uint8_t  mask  )

inlinestatic

Set a bit at a bus device register or memory address.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
mask	The mask value of the bit to set.

Returns

Nothing

References bus_get(), and bus_put().

uint8_t bus_reg_fieldget	(	bus_desc_t *	bus,
		uint8_t	addr,
		uint8_t	mask
	)

Read a field stored at a device register or memory address.

This routine reads a specified value from a bit field within a 1-Byte device register or memory address. The set bits in the mask parameter determine the field location. For example, if the mask is 30h and the value AFh is stored in the register, the value 2h will be returned.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
mask	The mask of the field to set.

Returns

The value stored in the register or memory field.

Sensor Platform Board ConfigurationThis routine reads a specified value from a bit field within a 1-Byte device register or memory address. The set bits in the mask parameter determine the field location. For example, if the mask is 30h and the value AFh is stored in the register, the value 2h will be returned.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
mask	The mask of the field to set.

Returns

The value stored in the register or memory field.

References bus_get().

void bus_reg_fieldset	(	bus_desc_t *	bus,
		uint8_t	addr,
		uint8_t	mask,
		uint8_t	value
	)

Write a field stored at a device register or memory address.

This routine writes a specified value to a bit field within a 1-Byte device register or memory address. The set bits in the mask parameter determine the field location. For example, if the mask is 30h and the value is 2h, the value 20h will be bitwise logically OR'd into the 1-Byte register value after clearing the bit values in the field.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
mask	The mask of the field to set.
value	The value of the field to set.

Returns

Nothing

References bus_get(), and bus_put().

size_t bus_write	(	bus_desc_t *	bus,
		uint8_t	addr,
		const void *	data,
		size_t	count
	)

Write multiple Bytes to a bus interface.

Parameters

bus	An initialized bus interface descriptor.
addr	The device register or memory address.
data	The source write buffer address.
count	The source write buffer size (Bytes).

Returns

The number of Bytes written, which may be less than the requested number of Bytes in the event of an error.

Referenced by bus_put().