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

struct	usart_spi_options

struct	USART_struct

Macros
#define	USART_BAUD_1200 0x00

#define	USART_BAUD_19200 0x04

#define	USART_BAUD_2400 0x01

#define	USART_BAUD_38400 0x05

#define	USART_BAUD_4800 0x02

#define	USART_BAUD_57600 0x06

#define	USART_BAUD_9600 0x03

#define	USART_BAUD_UNDEFINED 0xFF

#define	USART_CHSIZE00_bm 0x02 /* Character Size 00 bit 1 mask. */

#define	USART_CHSIZE00_bp 1 /* Character Size bit 00 position. */

#define	USART_CHSIZE01_bm 0x04 /* Character Size 10 bit 1 mask. */

#define	USART_CHSIZE01_bp 2 /* Character Size 10 bit position. */

#define	USART_CHSIZE01C_gm 0x06 /* Character Size 10 bit 1 mask. */

#define	USART_CHSIZE01C_gp 1 /* Character Size 10 bit position. */

#define	USART_CHSIZE2_bm 0x04 /* Character Size bit mask. */

#define	USART_CHSIZE2_bp 2 /* Character Size bit position. */

#define	USART_DOR_bm 0x08 /* Data Over Run bit mask.*/

#define	USART_DOR_bp 3 /* Data Over Run bit position.*/

#define	USART_DORD_bm 0x04 /* Data order bit mask. */

#define	USART_DORD_bp 2 /* Data order bit position. */

#define	USART_DRE_bm 0x20 /* DATA Register Empty Bit mask.*/

#define	USART_DRE_bp 5 /* DATA Register Empty bit position.*/

#define	USART_DRIE_bm 0x20 /* Data register empty interrupt Enable bit mask.*/

#define	USART_DRIE_bp 5 /* Data register empty interrupt Enable bit position.*/

#define	USART_FE_bm 0x10 /* Frame Error bit mask.*/

#define	USART_FE_bp 4 /Frame error bit position./

#define	USART_MPCM_bm 0x01 /* Multi Processor bit mask.*/

#define	USART_MPMC_bp 0 /* Multi processor bit position.*/

#define	USART_PMODE00_bm 0x10 /* USART Parity Mode Select 00 bit mask.*/

#define	USART_PMODE00_bp 4 /* USART Parity Mode Select 00 bit position.*/

#define	USART_PMODE01_bm 0x20 /* USART Parity Mode Select 01 bit mask.*/

#define	USART_PMODE01_bp 5 /* USART Parity Mode Select 01 bit position.*/

#define	USART_PMODE_gm 0x30 /* USART Parity Mode Select grp mask.*/

#define	USART_PMODE_gp 4 /* USART Parity Mode Select grp position.*/

#define	USART_RXB8_bm 0x02 /* Transmit bit 8 bit mask. */

#define	USART_RXB8_bp 1 /* Transmit bit 8 bit position. */

#define	USART_RXC_bm 0x80 /* RX complete bit mask.*/

#define	USART_RXC_bp 7 /* RX complete bit position.*/

#define	USART_RXCIE_bm 0x80 /* RX complete interrupt Enable bit mask.*/

#define	USART_RXCIE_bp 7 /* RX complete interrupt Enable bit position.*/

#define	USART_RXEN_bm 0x10 /* Receiver Enable bit mask. */

#define	USART_RXEN_bp 4 /* Receiver Enable bit position. */

#define	USART_STOPB_bm 0x08 /* USART stop bit mask.*/

#define	USART_STOPB_bp 3 /* USART stop bit Position.*/

#define	USART_TXB8_bm 0x01 /* Transmit bit 8 bit mask. */

#define	USART_TXB8_bp 0 /* Transmit bit 8 bit position. */

#define	USART_TXC_bm 0x40 /* TX complete bit mask.*/

#define	USART_TXC_bp 6 /* TX complete bit position.*/

#define	USART_TXCIE_bm 0x40 /* TX complete interrupt Enable bit mask.*/

#define	USART_TXCIE_bp 6 /* TX complete interrupt Enable bit position.*/

#define	USART_TXEN_bm 0x08 /* Transmitter Enable bit mask. */

#define	USART_TXEN_bp 3 /* Transmitter Enable bit position. */

#define	USART_U2X_bm 0x02 /* Double TX speed bit mask.*/

#define	USART_U2X_bp 1 /* Double TX speed bit position.*/

#define	USART_UCPHA_bm 0x02 /* Clock Phase bit mask. */

#define	USART_UCPHA_bp 1 /* Clock Phase bit position. */

#define	USART_UCPOL_bm 0x01 /* Sync mode Pol bit 1 mask. */

#define	USART_UCPOL_bp 0 /Sync mode Pol bit 0 position /

#define	USART_UMSEL00_bm 0x40 /* USART Mode Select 00 bit mask.*/

#define	USART_UMSEL00_bp 6 /* USART Mode Select 00 bit position.*/

#define	USART_UMSEL01_bm 0x80 /* USART Mode Select 01 bit mask.*/

#define	USART_UMSEL01_bp 7 /* USART Mode Select 01 bit position.*/

#define	USART_UMSEL01_gm 0xC0 /* USART Mode Select 01 grp mask.*/

#define	USART_UMSEL01_gp 6 /* USART Mode Select 01 grp position.*/

#define	USART_UPE_bm 0x04 /* Parity error bit mask.*/

#define	USART_UPE_bp 2 /* Parity error bit position.*/

#define	USARTA0

#define	USARTA1

Typedefs
typedef volatile uint16_t	register16_t

typedef volatile uint8_t	register8_t

typedef enum USART_CHSIZE_enum	USART_CHSIZE_t

typedef enum USART_CMODE_enum	USART_CMODE_t

typedef enum USART_PMODE_enum	USART_PMODE_t

typedef struct usart_rs232_options	usart_rs232_options_t

typedef struct usart_spi_options	usart_spi_options_t

typedef struct USART_struct	USART_t

Enumerations
enum	USART_CHSIZE_enum { USART_CHSIZE_5BIT_gc = (0x00), USART_CHSIZE_6BIT_gc = (0x01), USART_CHSIZE_7BIT_gc = (0x02), USART_CHSIZE_8BIT_gc = (0x03), USART_CHSIZE_9BIT_gc = (0x07), USART_CHSIZE_5BIT_gc = (0x00), USART_CHSIZE_6BIT_gc = (0x01), USART_CHSIZE_7BIT_gc = (0x02), USART_CHSIZE_8BIT_gc = (0x03), USART_CHSIZE_9BIT_gc = (0x07) }

enum	USART_CMODE_enum { USART_CMODE_ASYNCHRONOUS_gc = (0x00 << USART_UMSEL01_gp), USART_CMODE_SYNCHRONOUS_gc = (0x01 << USART_UMSEL01_gp), USART_CMODE_IRDA_gc = (0x02 << USART_UMSEL01_gp), USART_CMODE_MSPI_gc = (0x03 << USART_UMSEL01_gp), USART_CMODE_ASYNCHRONOUS_gc = (0x00 << USART_UMSEL01_gp), USART_CMODE_SYNCHRONOUS_gc = (0x01 << USART_UMSEL01_gp), USART_CMODE_IRDA_gc = (0x02 << USART_UMSEL01_gp), USART_CMODE_MSPI_gc = (0x03 << USART_UMSEL01_gp) }

enum	USART_PMODE_enum { USART_PMODE_DISABLED_gc = (0x00 << USART_PMODE_gp), USART_PMODE_EVEN_gc = (0x02 << USART_PMODE_gp), USART_PMODE_ODD_gc = (0x03 << USART_PMODE_gp), USART_PMODE_DISABLED_gc = (0x00 << USART_PMODE_gp), USART_PMODE_EVEN_gc = (0x02 << USART_PMODE_gp), USART_PMODE_ODD_gc = (0x03 << USART_PMODE_gp) }

Functions
static	PROGMEM_DECLARE (uint16_t, baudctrl_1mhz[])

static	PROGMEM_DECLARE (uint16_t, baudctrl_8mhz[])

static	PROGMEM_DECLARE (uint16_t, baudctrl_16mhz[])

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

static void	usart_data_empty_interrupt_disable (USART_t *usart)
	Disable USART data register empty interrupt. More...

static void	usart_data_empty_interrupt_enable (USART_t *usart)
	Enable USART data register empty interrupt. More...

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

static void	usart_double_baud_disable (USART_t *usart)
	Disable the Doubling of USART transmission speed. More...

static void	usart_double_baud_enable (USART_t *usart)
	Double the USART transmission speed. 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...

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

static void	usart_rx_complete_interrupt_disable (USART_t *usart)
	Disable USART receive complete interrupt. More...

static void	usart_rx_complete_interrupt_enable (USART_t *usart)
	Enable USART receive complete interrupt. 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 pre calculated BAUDCTRL values stored in program memory. More...

static void	usart_set_mode (USART_t *usart, USART_CMODE_t usartmode)
	Set the mode the USART run in. 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_complete_interrupt_disable (USART_t *usart)
	Disable USART transmit complete interrupt. More...

static void	usart_tx_complete_interrupt_enable (USART_t *usart)
	Enable USART transmit complete interrupt. 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...

Quick start guide for USART module

This is the quick start guide for the USART module, with step-by-step instructions on how to configure and use the driver in a selection of use cases.The use cases contain several code fragments. The code fragments in the steps for setup can be copied into a custom initialization function, while the steps for usage can be copied into, e.g., the main application function.

Basic use case - transmit a character

USART use cases

Basic use case - transmit a character

In this use case, the USART module is configured for:

Using USARTA1
Baudrate: 9600
Character length: 8 bit
Parity mode: Disabled
Stop bit: None
RS232 mode

Setup steps

Prerequisites

System Clock Management

Example code

The following configuration must be added to the project (typically to a conf_usart_example.h file, but it can also be added to your main application file.)

#define USART_SERIAL                     &USARTA1
#define USART_SERIAL_BAUDRATE            9600
#define USART_SERIAL_CHAR_LENGTH         USART_CHSIZE_8BIT_gc
#define USART_SERIAL_PARITY              USART_PMODE_DISABLED_gc
#define USART_SERIAL_STOP_BIT            false

Add to application initialization:

 sysclk_init();
 static usart_rs232_options_t USART_SERIAL_OPTIONS = {
    .baudrate = USART_SERIAL_BAUDRATE,
    .charlength = USART_SERIAL_CHAR_LENGTH,
    .paritytype = USART_SERIAL_PARITY,
    .stopbits = USART_SERIAL_STOP_BIT
 };
usart_init_rs232(USART_SERIAL, &USART_SERIAL_OPTIONS);

Workflow

Initialize system clock:
- sysclk_init();
- Note
  Not always required, but since the usart_group driver is dependent on System Clock Management it is good practise to initialize this module.
Create USART options struct:
- static usart_rs232_options_t USART_SERIAL_OPTIONS = {
  
  .baudrate = USART_SERIAL_BAUDRATE,
  
  .charlength = USART_SERIAL_CHAR_LENGTH,
  
  .paritytype = USART_SERIAL_PARITY,
  
  .stopbits = USART_SERIAL_STOP_BIT
  
  };
Initialize in RS232 mode:
- usart_init_rs232(USART_SERIAL, &USART_SERIAL_OPTIONS);

Usage steps

Example code

Add to application C-file:

usart_putchar(USART_SERIAL, 'a');

Workflow

Send an 'a' character via USART
- usart_putchar(USART_SERIAL, 'a');

USART receive character and echo back

In this use case, the USART module is configured for:

Using USARTA1
Baudrate: 9600
Character length: 8 bit
Parity mode: Disabled
Stop bit: None
RS232 mode

The use case waits for a received character on the configured USART and echoes the character back to the same USART.

Setup steps

Prerequisites

System Clock Management

Example code

The following configuration must be added to the project (typically to a conf_usart.h file, but it can also be added to your main application file.):
#define USART_SERIAL &USARTA1

#define USART_SERIAL_BAUDRATE 9600

#define USART_SERIAL_CHAR_LENGTH USART_CHSIZE_8BIT_gc

#define USART_SERIAL_PARITY USART_PMODE_DISABLED_gc

#define USART_SERIAL_STOP_BIT false

A variable for the received byte must be added:

uint8_t received_byte;

Add to application initialization:

 sysclk_init();
 static usart_rs232_options_t USART_SERIAL_OPTIONS = {
    .baudrate = USART_SERIAL_BAUDRATE,
    .charlength = USART_SERIAL_CHAR_LENGTH,
    .paritytype = USART_SERIAL_PARITY,
    .stopbits = USART_SERIAL_STOP_BIT
 };
usart_init_rs232(USART_SERIAL, &USART_SERIAL_OPTIONS);

Workflow

Initialize system clock:
- sysclk_init();
- Note
  Not always required, but since the usart_group driver is dependent on System Clock Management it is good practise to initialize this module.
Create USART options struct:
- static usart_rs232_options_t USART_SERIAL_OPTIONS = {
  
  .baudrate = USART_SERIAL_BAUDRATE,
  
  .charlength = USART_SERIAL_CHAR_LENGTH,
  
  .paritytype = USART_SERIAL_PARITY,
  
  .stopbits = USART_SERIAL_STOP_BIT
  
  };
Initialize in RS232 mode:
- megarf_usart_init_rs232(USART_SERIAL, &USART_SERIAL_OPTIONS);

Usage steps

Example code

Add to, e.g., main loop in application C-file:

received_byte = usart_getchar(USART_SERIAL);

usart_putchar(USART_SERIAL, received_byte);

Workflow

Wait for reception of a character:
- received_byte = usart_getchar(USART_SERIAL);
Echo the character back:
- usart_putchar(USART_SERIAL, received_byte);

#define USART_BAUD_1200 0x00

#define USART_BAUD_19200 0x04

#define USART_BAUD_2400 0x01

#define USART_BAUD_38400 0x05

#define USART_BAUD_4800 0x02

#define USART_BAUD_57600 0x06

#define USART_BAUD_9600 0x03

#define USART_BAUD_UNDEFINED 0xFF

#define USART_CHSIZE00_bm 0x02 /* Character Size 00 bit 1 mask. */

#define USART_CHSIZE00_bp 1 /* Character Size bit 00 position. */

#define USART_CHSIZE01_bm 0x04 /* Character Size 10 bit 1 mask. */

#define USART_CHSIZE01_bp 2 /* Character Size 10 bit position. */

#define USART_CHSIZE01C_gm 0x06 /* Character Size 10 bit 1 mask. */

Referenced by usart_format_set().

#define USART_CHSIZE01C_gp 1 /* Character Size 10 bit position. */

Referenced by usart_format_set().

#define USART_CHSIZE2_bm 0x04 /* Character Size bit mask. */

Referenced by usart_format_set().

#define USART_CHSIZE2_bp 2 /* Character Size bit position. */

Referenced by usart_format_set().

#define USART_DOR_bm 0x08 /* Data Over Run bit mask.*/

#define USART_DOR_bp 3 /* Data Over Run bit position.*/

#define USART_DORD_bm 0x04 /* Data order bit mask. */

#define USART_DORD_bp 2 /* Data order bit position. */

#define USART_DRE_bm 0x20 /* DATA Register Empty Bit mask.*/

Referenced by usart_data_register_is_empty().

#define USART_DRE_bp 5 /* DATA Register Empty bit position.*/

#define USART_DRIE_bm 0x20 /* Data register empty interrupt Enable bit mask.*/

Referenced by usart_data_empty_interrupt_disable(), and usart_data_empty_interrupt_enable().

#define USART_DRIE_bp 5 /* Data register empty interrupt Enable bit position.*/

#define USART_FE_bm 0x10 /* Frame Error bit mask.*/

#define USART_FE_bp 4 /*Frame error bit position.*/

#define USART_MPCM_bm 0x01 /* Multi Processor bit mask.*/

#define USART_MPMC_bp 0 /* Multi processor bit position.*/

#define USART_PMODE00_bm 0x10 /* USART Parity Mode Select 00 bit mask.*/

#define USART_PMODE00_bp 4 /* USART Parity Mode Select 00 bit position.*/

#define USART_PMODE01_bm 0x20 /* USART Parity Mode Select 01 bit mask.*/

#define USART_PMODE01_bp 5 /* USART Parity Mode Select 01 bit position.*/

#define USART_PMODE_gm 0x30 /* USART Parity Mode Select grp mask.*/

Referenced by usart_format_set().

#define USART_PMODE_gp 4 /* USART Parity Mode Select grp position.*/

#define USART_RXB8_bm 0x02 /* Transmit bit 8 bit mask. */

#define USART_RXB8_bp 1 /* Transmit bit 8 bit position. */

#define USART_RXC_bm 0x80 /* RX complete bit mask.*/

Referenced by usart_rx_complete_interrupt_disable(), usart_rx_complete_interrupt_enable(), and usart_rx_is_complete().

#define USART_RXC_bp 7 /* RX complete bit position.*/

#define USART_RXCIE_bm 0x80 /* RX complete interrupt Enable bit mask.*/

#define USART_RXCIE_bp 7 /* RX complete interrupt Enable bit position.*/

#define USART_RXEN_bm 0x10 /* Receiver Enable bit mask. */

Referenced by usart_rx_disable(), and usart_rx_enable().

#define USART_RXEN_bp 4 /* Receiver Enable bit position. */

#define USART_STOPB_bm 0x08 /* USART stop bit mask.*/

Referenced by usart_format_set().

#define USART_STOPB_bp 3 /* USART stop bit Position.*/

Referenced by usart_format_set().

#define USART_TXB8_bm 0x01 /* Transmit bit 8 bit mask. */

#define USART_TXB8_bp 0 /* Transmit bit 8 bit position. */

#define USART_TXC_bm 0x40 /* TX complete bit mask.*/

Referenced by usart_clear_tx_complete(), usart_tx_complete_interrupt_disable(), usart_tx_complete_interrupt_enable(), and usart_tx_is_complete().

#define USART_TXC_bp 6 /* TX complete bit position.*/

#define USART_TXCIE_bm 0x40 /* TX complete interrupt Enable bit mask.*/

#define USART_TXCIE_bp 6 /* TX complete interrupt Enable bit position.*/

#define USART_TXEN_bm 0x08 /* Transmitter Enable bit mask. */

Referenced by usart_tx_disable(), and usart_tx_enable().

#define USART_TXEN_bp 3 /* Transmitter Enable bit position. */

#define USART_U2X_bm 0x02 /* Double TX speed bit mask.*/

Referenced by usart_double_baud_disable(), and usart_double_baud_enable().

#define USART_U2X_bp 1 /* Double TX speed bit position.*/

#define USART_UCPHA_bm 0x02 /* Clock Phase bit mask. */

#define USART_UCPHA_bp 1 /* Clock Phase bit position. */

#define USART_UCPOL_bm 0x01 /* Sync mode Pol bit 1 mask. */

#define USART_UCPOL_bp 0 /*Sync mode Pol bit 0 position */

#define USART_UMSEL00_bm 0x40 /* USART Mode Select 00 bit mask.*/

#define USART_UMSEL00_bp 6 /* USART Mode Select 00 bit position.*/

#define USART_UMSEL01_bm 0x80 /* USART Mode Select 01 bit mask.*/

#define USART_UMSEL01_bp 7 /* USART Mode Select 01 bit position.*/

#define USART_UMSEL01_gm 0xC0 /* USART Mode Select 01 grp mask.*/

Referenced by usart_set_mode().

#define USART_UMSEL01_gp 6 /* USART Mode Select 01 grp position.*/

#define USART_UPE_bm 0x04 /* Parity error bit mask.*/

#define USART_UPE_bp 2 /* Parity error bit position.*/

#define USARTA0

Value:

(*(USART_t *)0xC0) /* Universal Asynchronous

* Receiver-Transmitter A0 */

USART_struct

Definition: usart_mega.h:86

#define USARTA1

Value:

(*(USART_t *)0XC8) /* Universal Asynchronous

* Receiver-Transmitter A1 */

USART_struct

Definition: usart_mega.h:86

typedef volatile uint16_t register16_t

typedef volatile uint8_t register8_t

typedef enum USART_CHSIZE_enum USART_CHSIZE_t

typedef enum USART_CMODE_enum USART_CMODE_t

typedef enum USART_PMODE_enum USART_PMODE_t

typedef struct usart_rs232_options usart_rs232_options_t

typedef struct usart_spi_options usart_spi_options_t

typedef struct USART_struct USART_t

enum USART_CHSIZE_enum

Enumerator
USART_CHSIZE_5BIT_gc
USART_CHSIZE_6BIT_gc
USART_CHSIZE_7BIT_gc
USART_CHSIZE_8BIT_gc
USART_CHSIZE_9BIT_gc
USART_CHSIZE_5BIT_gc
USART_CHSIZE_6BIT_gc
USART_CHSIZE_7BIT_gc
USART_CHSIZE_8BIT_gc
USART_CHSIZE_9BIT_gc

enum USART_CMODE_enum

Enumerator
USART_CMODE_ASYNCHRONOUS_gc
USART_CMODE_SYNCHRONOUS_gc
USART_CMODE_IRDA_gc
USART_CMODE_MSPI_gc
USART_CMODE_ASYNCHRONOUS_gc
USART_CMODE_SYNCHRONOUS_gc
USART_CMODE_IRDA_gc
USART_CMODE_MSPI_gc

enum USART_PMODE_enum

Enumerator
USART_PMODE_DISABLED_gc
USART_PMODE_EVEN_gc
USART_PMODE_ODD_gc
USART_PMODE_DISABLED_gc
USART_PMODE_EVEN_gc
USART_PMODE_ODD_gc

static PROGMEM_DECLARE	(	uint16_t	,
		baudctrl_1mhz	[]
	)

static

static PROGMEM_DECLARE	(	uint16_t	,
		baudctrl_8mhz	[]
	)

static

static PROGMEM_DECLARE	(	uint16_t	,
		baudctrl_16mhz	[]
	)

static

static void usart_clear_tx_complete ( USART_t * usart )

inlinestatic

Clear TX complete interrupt flag.

TX flag is clear after complete transmission, automatically.

Parameters

usart The USART module.

References USART_struct::UCSRnA, and USART_TXC_bm.

Referenced by usart_spi_transmit().

static void usart_data_empty_interrupt_disable ( USART_t * usart )

inlinestatic

Disable USART data register empty interrupt.

Parameters

usart Pointer to the USART module.

References USART_DRIE_bm.

static void usart_data_empty_interrupt_enable ( USART_t * usart )

inlinestatic

Enable USART data register empty interrupt.

Parameters

usart Pointer to the USART module.

References USART_DRIE_bm.

static bool usart_data_register_is_empty ( USART_t * usart )

inlinestatic

Check if data register empty flag is set.

Parameters

usart The USART module.

References USART_DRE_bm.

Referenced by usart_spi_transmit().

static void usart_double_baud_disable ( USART_t * usart )

inlinestatic

Disable the Doubling of USART transmission speed.

Parameters

usart The USART module.

References USART_struct::UCSRnA, and USART_U2X_bm.

static void usart_double_baud_enable ( USART_t * usart )

inlinestatic

Double the USART transmission speed.

Parameters

usart The USART module.

References USART_struct::UCSRnA, and USART_U2X_bm.

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.

References USART_CHSIZE01C_gm, USART_CHSIZE01C_gp, USART_CHSIZE2_bm, USART_CHSIZE2_bp, USART_PMODE_gm, USART_STOPB_bm, and USART_STOPB_bp.

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 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_struct::UDR, and usart_rx_is_complete().

Referenced by main(), run_loopback_syncmode_test(), run_loopback_test(), 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 successful
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_get_source_clock_hz(), USART_CMODE_ASYNCHRONOUS_gc, usart_enable_module_clock(), usart_format_set(), usart_rx_enable(), usart_set_baudrate(), usart_set_mode(), and usart_tx_enable().

Referenced by main(), run_check_registers_test(), run_loopback_test(), 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_configure_port_pin(), IOPORT_CREATE_PIN, IOPORT_DIR_OUTPUT, IOPORT_INIT_HIGH, ioport_pin_to_mask(), ioport_pin_to_port(), usart_spi_options::spimode, sysclk_get_source_clock_hz(), USART_struct::UBRR, USART_struct::UCSRnC, USART_CMODE_MSPI_gc, USART_DORD_bm, usart_enable_module_clock(), usart_rx_enable(), usart_set_mode(), usart_spi_set_baudrate(), usart_tx_enable(), USART_UCPHA_bm, and USART_UCPOL_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 usart_spi_transmit().

status_code_t 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, USART_struct::UDR, and usart_data_register_is_empty().

Referenced by example_cmp1_int_cb(), example_cmp2_int_cb(), example_cmp3_int_cb(), example_ovf_int_cb(), main(), run_loopback_syncmode_test(), run_loopback_test(), and usart_serial_putchar().

static void usart_rx_complete_interrupt_disable ( USART_t * usart )

inlinestatic

Disable USART receive complete interrupt.

Parameters

usart Pointer to the USART module.

References USART_RXC_bm.

static void usart_rx_complete_interrupt_enable ( USART_t * usart )

inlinestatic

Enable USART receive complete interrupt.

Parameters

usart Pointer to the USART module.

References USART_RXC_bm.

static void usart_rx_disable ( USART_t * usart )

inlinestatic

Disable USART receiver.

Parameters

usart Pointer to the USART module.

References USART_RXEN_bm.

static void usart_rx_enable ( USART_t * usart )

inlinestatic

Enable USART receiver.

Parameters

usart Pointer to the USART module

References USART_RXEN_bm.

static bool usart_rx_is_complete ( USART_t * usart )

inlinestatic

Checks if the RX complete interrupt flag is set.

Parameters

usart The USART module.

References USART_RXC_bm.

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.)

References USART_struct::UBRR, USART_struct::UCSRnA, and USART_U2X_bm.

Referenced by run_baudrate_test(), and usart_init_rs232().

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

Set the baudrate using pre calculated BAUDCTRL values stored in program memory.

Note: This function only works for cpu_hz 1Mhz, 8Mhz or 16Mhz 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_struct::UBRR, USART_BAUD_UNDEFINED, and usart_get_baud_offset().

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.

References USART_UMSEL01_gm.

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.

References USART_struct::UBRR.

Referenced by run_loopback_syncmode_test(), and 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().

static void usart_tx_complete_interrupt_disable ( USART_t * usart )

inlinestatic

Disable USART transmit complete interrupt.

Parameters

usart Pointer to the USART module.

References USART_TXC_bm.

static void usart_tx_complete_interrupt_enable ( USART_t * usart )

inlinestatic

Enable USART transmit complete interrupt.

Parameters

usart Pointer to the USART module.

References USART_TXC_bm.

static void usart_tx_disable ( USART_t * usart )

inlinestatic

Disable USART transmitter.

Parameters

usart Pointer to the USART module.

References USART_TXEN_bm.

static void usart_tx_enable ( USART_t * usart )

inlinestatic

Enable USART transmitter.

Parameters

usart Pointer to the USART module.

References USART_TXEN_bm.

static bool usart_tx_is_complete ( USART_t * usart )

inlinestatic

Checks if the TX complete interrupt flag is set.

Parameters

usart The USART module.

References USART_TXC_bm.

Referenced by usart_spi_transmit().

Microchip® Advanced Software Framework

Dependencies

Modules

Data Structures

Macros

Typedefs

Enumerations

Functions

Quick start guide for USART module

Basic use case - transmit a character

USART use cases

Basic use case - transmit a character

Setup steps

Prerequisites

Example code

Workflow

Usage steps

Example code

Workflow

USART receive character and echo back

Setup steps

Prerequisites

Example code

Workflow

Usage steps

Example code

Workflow