This is a driver for configuring, enabling, disabling and use of the on-chip USART.

Dependencies

The USART module depends on the following modules:

System Clock Management for peripheral clock control.
port_driver_group for peripheral io port control.

Modules
	Related Project(s)
	In this section you can find all the projects related to the USART module (USART).

	Quick Start Guide(s)
	In this section you can find a list of all Quick Start guides related to the USART module (USART).

Data Structures
struct	usart_rs232_options
	Input parameters when initializing RS232 and similar modes. More...

struct	usart_spi_options
	Input parameters when initializing SPI master mode. More...

Macros
#define	USART_BAUD_1200 0x00
	Offset in lookup table for baudrate 1200. More...

#define	USART_BAUD_19200 0x04
	Offset in lookup table for baudrate 19200. More...

#define	USART_BAUD_2400 0x01
	Offset in lookup table for baudrate 2400. More...

#define	USART_BAUD_38400 0x05
	Offset in lookup table for baudrate 38400. More...

#define	USART_BAUD_4800 0x02
	Offset in lookup table for baudrate 4800. More...

#define	USART_BAUD_57600 0x06
	Offset in lookup table for baudrate 57600. More...

#define	USART_BAUD_9600 0x03
	Offset in lookup table for baudrate 9600. More...

#define	USART_BAUD_UNDEFINED 0xFF
	Baudrate not in lookup table. More...

Typedefs
typedef struct usart_rs232_options	usart_rs232_options_t
	Input parameters when initializing RS232 and similar modes. More...

typedef struct usart_spi_options	usart_spi_options_t
	Input parameters when initializing SPI master mode. More...

Enumerations
enum	usart_int_level_t { USART_INT_LVL_OFF = 0x00, USART_INT_LVL_LO = 0x01, USART_INT_LVL_MED = 0x02, USART_INT_LVL_HI = 0x03 }
	USART interrupt levels. More...

Functions
static	PROGMEM_DECLARE (uint16_t, baudctrl_2mhz[])
	Lookup table containing baudctrl values for CPU frequency 2 Mhz. More...

static	PROGMEM_DECLARE (uint16_t, baudctrl_32mhz[])
	Lookup table containing baudctrl values for CPU frequency 32 Mhz. More...

static void	usart_clear_rx_complete (USART_t *usart)
	Clear RX complete interrupt flag. More...

static void	usart_clear_tx_complete (USART_t *usart)
	Clear TX complete interrupt flag. More...

static bool	usart_data_register_is_empty (USART_t *usart)
	Check if data register empty flag is set. More...

static void	usart_format_set (USART_t *usart, USART_CHSIZE_t charSize, USART_PMODE_t parityMode, bool twoStopBits)
	Configure the USART frame format. More...

static uint8_t	usart_get (USART_t *usart)
	Read a data to the USART data register. More...

uint8_t	usart_getchar (USART_t *usart)
	Receive a data with the USART module. More...

bool	usart_init_rs232 (USART_t usart, const usart_rs232_options_t opt)
	Initialize USART in RS232 mode. More...

void	usart_init_spi (USART_t usart, const usart_spi_options_t opt)
	Initialize USART in SPI master mode. More...

static void	usart_put (USART_t *usart, uint8_t txdata)
	Write a data to the USART data register. More...

enum status_code	usart_putchar (USART_t *usart, uint8_t c)
	Send a data with the USART module. More...

static void	usart_rx_disable (USART_t *usart)
	Disable USART receiver. More...

static void	usart_rx_enable (USART_t *usart)
	Enable USART receiver. More...

static bool	usart_rx_is_complete (USART_t *usart)
	Checks if the RX complete interrupt flag is set. More...

bool	usart_set_baudrate (USART_t *usart, uint32_t baud, uint32_t cpu_hz)
	Set the baudrate value in the USART module. More...

void	usart_set_baudrate_precalculated (USART_t *usart, uint32_t baud, uint32_t cpu_hz)
	Set the baudrate using precalculated BAUDCTRL values from PROGMEM. More...

void	usart_set_bsel_bscale_value (USART_t *usart, uint16_t bsel, uint8_t bscale)
	Set the baudrate by setting the BSEL and BSCALE values in the USART. More...

static void	usart_set_dre_interrupt_level (USART_t *usart, enum usart_int_level_t level)
	Set USART DRE interrupt level. More...

static void	usart_set_mode (USART_t *usart, USART_CMODE_t usartmode)
	Set the mode the USART run in. More...

static void	usart_set_rx_interrupt_level (USART_t *usart, enum usart_int_level_t level)
	Set USART RXD interrupt level. More...

static void	usart_set_tx_interrupt_level (USART_t *usart, enum usart_int_level_t level)
	Set USART TXD interrupt level. More...

void	usart_spi_set_baudrate (USART_t *usart, uint32_t baud, uint32_t cpu_hz)
	Set the baudrate value in the USART_SPI module. More...

static uint8_t	usart_spi_transmit (USART_t *usart, uint8_t txdata)
	Performs a data transfer on the USART in SPI mode. More...

static void	usart_tx_disable (USART_t *usart)
	Disable USART transmitter. More...

static void	usart_tx_enable (USART_t *usart)
	Enable USART transmitter. More...

static bool	usart_tx_is_complete (USART_t *usart)
	Checks if the TX complete interrupt flag is set. More...

#define USART_BAUD_1200 0x00

Offset in lookup table for baudrate 1200.

Referenced by usart_get_baud_offset().

#define USART_BAUD_19200 0x04

Offset in lookup table for baudrate 19200.

Referenced by usart_get_baud_offset().

#define USART_BAUD_2400 0x01

Offset in lookup table for baudrate 2400.

Referenced by usart_get_baud_offset().

#define USART_BAUD_38400 0x05

Offset in lookup table for baudrate 38400.

Referenced by usart_get_baud_offset().

#define USART_BAUD_4800 0x02

Offset in lookup table for baudrate 4800.

Referenced by usart_get_baud_offset().

#define USART_BAUD_57600 0x06

Offset in lookup table for baudrate 57600.

Referenced by usart_get_baud_offset().

#define USART_BAUD_9600 0x03

Offset in lookup table for baudrate 9600.

Referenced by usart_get_baud_offset().

#define USART_BAUD_UNDEFINED 0xFF

Baudrate not in lookup table.

Referenced by usart_get_baud_offset(), and usart_set_baudrate_precalculated().

typedef struct usart_rs232_options usart_rs232_options_t

Input parameters when initializing RS232 and similar modes.

typedef struct usart_spi_options usart_spi_options_t

Input parameters when initializing SPI master mode.

enum usart_int_level_t

USART interrupt levels.

Enumerator
USART_INT_LVL_OFF
USART_INT_LVL_LO
USART_INT_LVL_MED
USART_INT_LVL_HI

static PROGMEM_DECLARE	(	uint16_t	,
		baudctrl_2mhz	[]
	)

static

Lookup table containing baudctrl values for CPU frequency 2 Mhz.

static PROGMEM_DECLARE	(	uint16_t	,
		baudctrl_32mhz	[]
	)

static

Lookup table containing baudctrl values for CPU frequency 32 Mhz.

static void usart_clear_rx_complete ( USART_t * usart )

inlinestatic

Clear RX complete interrupt flag.

Parameters

usart The USART module.

static void usart_clear_tx_complete ( USART_t * usart )

inlinestatic

Clear TX complete interrupt flag.

Parameters

usart The USART module.

Referenced by configure_sensor_platform(), ili9341_send_byte(), ili9341_wait_for_send_done(), and usart_spi_transmit().

static bool usart_data_register_is_empty ( USART_t * usart )

inlinestatic

Check if data register empty flag is set.

Parameters

usart The USART module.

Referenced by ili9341_send_byte(), usart_putchar(), usart_spi_is_tx_empty(), usart_spi_is_tx_ready(), and usart_spi_transmit().

static void usart_format_set	(	USART_t *	usart,
		USART_CHSIZE_t	charSize,
		USART_PMODE_t	parityMode,
		bool	twoStopBits
	)

inlinestatic

Configure the USART frame format.

Sets the frame format, Frame Size, parity mode and number of stop bits.

Parameters

usart	Pointer to the USART module
charSize	The character size. Use USART_CHSIZE_t type.
parityMode	The parity Mode. Use USART_PMODE_t type.
twoStopBits	Enable two stop bit mode. Use bool type.

Referenced by usart_init_rs232().

static uint8_t usart_get ( USART_t * usart )

inlinestatic

Read a data to the USART data register.

Parameters

usart The USART module.

Returns: The received data

Referenced by ili9341_read_byte(), and usart_spi_transmit().

uint8_t usart_getchar ( USART_t * usart )

Receive a data with the USART module.

This function returns the received data from the USART module.

Parameters

usart The USART module.

Returns: The received data.

References usart_rx_is_complete().

Referenced by main(), and usart_serial_getchar().

bool usart_init_rs232	(	USART_t *	usart,
		const usart_rs232_options_t *	opt
	)

Initialize USART in RS232 mode.

This function initializes the USART module in RS232 mode using the usart_rs232_options_t configuration structure and CPU frequency.

Parameters

usart	The USART module.
opt	The RS232 configuration option.

Return values

true	if the initialization was successfull
false	if the initialization failed (error in baud rate calculation)

References usart_rs232_options::baudrate, usart_rs232_options::charlength, usart_rs232_options::paritytype, usart_rs232_options::stopbits, sysclk_enable_peripheral_clock(), sysclk_get_per_hz(), usart_format_set(), usart_rx_enable(), usart_set_baudrate(), usart_set_mode(), and usart_tx_enable().

Referenced by main(), and usart_serial_init().

void usart_init_spi	(	USART_t *	usart,
		const usart_spi_options_t *	opt
	)

Initialize USART in SPI master mode.

This function initializes the USART module in SPI master mode using the usart_spi_options_t configuration structure and CPU frequency.

Parameters

usart	The USART module.
opt	The RS232 configuration option.

References usart_spi_options::baudrate, usart_spi_options::data_order, IOPORT_CREATE_PIN, IOPORT_DIR_OUTPUT, IOPORT_MODE_INVERT_PIN, IOPORT_MODE_TOTEM, IOPORT_PIN_LEVEL_HIGH, ioport_set_pin_dir(), ioport_set_pin_level(), ioport_set_pin_mode(), usart_spi_options::spimode, sysclk_enable_peripheral_clock(), sysclk_get_per_hz(), UNUSED, USART_DORD_bm, usart_rx_disable(), usart_rx_enable(), usart_set_mode(), usart_spi_set_baudrate(), usart_tx_enable(), and USART_UCPHA_bm.

Referenced by usart_spi_setup_device().

static void usart_put	(	USART_t *	usart,
		uint8_t	txdata
	)

inlinestatic

Write a data to the USART data register.

Parameters

usart	The USART module.
txdata	The data to be transmitted.

Referenced by ili9341_read_byte(), ili9341_send_byte(), and usart_spi_transmit().

enum status_code usart_putchar	(	USART_t *	usart,
		uint8_t	c
	)

Send a data with the USART module.

This function outputs a data using the USART module.

Parameters

usart	The USART module.
c	The data to send.

Returns: STATUS_OK

References STATUS_OK, and usart_data_register_is_empty().

Referenced by gfx_mono_screen_dump(), log_sha204(), main(), and usart_serial_putchar().

static void usart_rx_disable ( USART_t * usart )

inlinestatic

Disable USART receiver.

Parameters

usart Pointer to the USART module.

Referenced by ili9341_read_byte(), and usart_init_spi().

static void usart_rx_enable ( USART_t * usart )

inlinestatic

Enable USART receiver.

Parameters

usart Pointer to the USART module

Referenced by ili9341_read_byte(), usart_init_rs232(), and usart_init_spi().

static bool usart_rx_is_complete ( USART_t * usart )

inlinestatic

Checks if the RX complete interrupt flag is set.

Parameters

usart The USART module.

Referenced by ili9341_read_byte(), usart_getchar(), usart_spi_is_rx_full(), and usart_spi_is_rx_ready().

bool usart_set_baudrate	(	USART_t *	usart,
		uint32_t	baud,
		uint32_t	cpu_hz
	)

Set the baudrate value in the USART module.

This function sets the baudrate register with scaling regarding the CPU frequency and makes sure the baud rate is supported by the hardware. The function can be used if you don't want to calculate the settings yourself or changes to baudrate at runtime is required.

Parameters

usart	The USART module.
baud	The baudrate.
cpu_hz	The CPU frequency.

Return values

true	if the hardware supports the baud rate
false	if the hardware does not support the baud rate (i.e. it's either too high or too low.)

Referenced by usart_init_rs232().

void usart_set_baudrate_precalculated	(	USART_t *	usart,
		uint32_t	baud,
		uint32_t	cpu_hz
	)

Set the baudrate using precalculated BAUDCTRL values from PROGMEM.

Note: This function only works for cpu_hz 2Mhz or 32Mhz and baudrate values 1200, 2400, 4800, 9600, 19200, 38400 and 57600.

Parameters

usart	The USART module.
baud	The baudrate.
cpu_hz	The CPU frequency.

References Assert, PROGMEM_READ_WORD, USART_BAUD_UNDEFINED, and usart_get_baud_offset().

void usart_set_bsel_bscale_value	(	USART_t *	usart,
		uint16_t	bsel,
		uint8_t	bscale
	)

Set the baudrate by setting the BSEL and BSCALE values in the USART.

This function sets the selected BSEL and BSCALE value in the BAUDCTRL registers with BSCALE 0. For calculation options, see table 21-1 in XMEGA A manual.

Parameters

usart	The USART module.
bsel	Calculated BSEL value.
bscale	Calculated BSEL value.

static void usart_set_dre_interrupt_level	(	USART_t *	usart,
		enum usart_int_level_t	level
	)

inlinestatic

Set USART DRE interrupt level.

Sets the interrupt level on Data Register interrupt.

Parameters

usart	Pointer to the USART module.
level	Interrupt level of the DRE interrupt. Use USART_DREINTLVL_t type.

static void usart_set_mode	(	USART_t *	usart,
		USART_CMODE_t	usartmode
	)

inlinestatic

Set the mode the USART run in.

Set the mode the USART run in. The default mode is asynchronous mode.

Parameters

usart	Pointer to the USART module register section.
usartmode	Selects the USART mode. Use USART_CMODE_t type.

USART modes:

0x0 : Asynchronous mode.
0x1 : Synchronous mode.
0x2 : IrDA mode.
0x3 : Master SPI mode.

Referenced by usart_init_rs232(), and usart_init_spi().

static void usart_set_rx_interrupt_level	(	USART_t *	usart,
		enum usart_int_level_t	level
	)

inlinestatic

Set USART RXD interrupt level.

Sets the interrupt level on RX Complete interrupt.

Parameters

usart	Pointer to the USART module.
level	Interrupt level of the RXD interrupt.

static void usart_set_tx_interrupt_level	(	USART_t *	usart,
		enum usart_int_level_t	level
	)

inlinestatic

Set USART TXD interrupt level.

Sets the interrupt level on TX Complete interrupt.

Parameters

usart	Pointer to the USART module.
level	Interrupt level of the TXD interrupt.

void usart_spi_set_baudrate	(	USART_t *	usart,
		uint32_t	baud,
		uint32_t	cpu_hz
	)

Set the baudrate value in the USART_SPI module.

This function sets the baudrate register regarding the CPU frequency.

Parameters

usart	The USART(SPI) module.
baud	The baudrate.
cpu_hz	The CPU frequency.

Referenced by usart_init_spi().

static uint8_t usart_spi_transmit	(	USART_t *	usart,
		uint8_t	txdata
	)

inlinestatic

Performs a data transfer on the USART in SPI mode.

Parameters

usart	The USART module.
txdata	The data to be transmitted.

Returns: The received data

References usart_clear_tx_complete(), usart_data_register_is_empty(), usart_get(), usart_put(), and usart_tx_is_complete().

Referenced by ssd1306_write_command(), ssd1306_write_data(), st7565r_write_command(), st7565r_write_data(), usart_spi_read_packet(), usart_spi_read_single(), usart_spi_write_packet(), and usart_spi_write_single().

static void usart_tx_disable ( USART_t * usart )

inlinestatic

Disable USART transmitter.

Parameters

usart Pointer to the USART module.

static void usart_tx_enable ( USART_t * usart )

inlinestatic

Enable USART transmitter.

Parameters

usart Pointer to the USART module.

Referenced by usart_init_rs232(), and usart_init_spi().

static bool usart_tx_is_complete ( USART_t * usart )

inlinestatic

Checks if the TX complete interrupt flag is set.

Parameters

usart The USART module.

Referenced by configure_sensor_platform(), ili9341_wait_for_send_done(), and usart_spi_transmit().

Microchip® Advanced Software Framework

Dependencies

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions