uart.h File Reference

Wrapper for UART-driver of Atmel for Xmega. More...

#include "avr_compiler.h"
#include "usart_driver.h"

Go to the source code of this file.

Macros
#define	UART_NO_DATA   0x0100
	Macro UART_NO_DATA is returned by uart_getc when no data is present.

Functions
uint16_t	calc_bsel (uint32_t f_cpu, uint32_t baud, int8_t scale, uint8_t clk2x)
	Calculates the baud rate value BSEL. More...
uint16_t	uart_getc (USART_data_t *uart)
	Get a byte from the circular receive buffer. More...
void	uart_putc (USART_data_t *uart, uint8_t data)
	Write a byte to the circular transmit buffer. More...
void	uart_puts (USART_data_t *uart, char *s)
	Write a string to the circulair transmit buffer. More...
void	set_usart_txrx_direction (USART_t *usart)
	Set direction for the transmit and receive pin. More...
void	init_uart (USART_data_t *uart, USART_t *usart, uint32_t f_cpu, uint32_t baud, uint8_t clk2x)
	Initializes the UART. More...
void	init_uart_levels (USART_data_t *uart, USART_t *usart, uint32_t f_cpu, uint32_t baud, uint8_t clk2x, USART_RXCINTLVL_t rxcIntLevel, USART_DREINTLVL_t dreIntLevel)
	Initializes the UART. More...
	ISR (USARTC0_RXC_vect)
	Interrupt Service Routine for receiving with UARTC0. This ISR is only defined if the macro ENABLE_UART_C0 is defined.
	ISR (USARTC0_DRE_vect)
	Interrupt Service Routine for transmitting with UARTC0. This ISR is only defined if the macro ENABLE_UART_C0 is defined.
	ISR (USARTC1_RXC_vect)
	Interrupt Service Routine for receiving with UARTC1. This ISR is only defined if the macro ENABLE_UART_C1 is defined.
	ISR (USARTC1_DRE_vect)
	Interrupt Service Routine for transmitting with UARTC1. This ISR is only defined if the macro ENABLE_UART_C1 is defined.
	ISR (USARTD0_RXC_vect)
	Interrupt Service Routine for receiving with UARTD0. This ISR is only defined if the macro ENABLE_UART_D0 is defined.
	ISR (USARTD0_DRE_vect)
	Interrupt Service Routine for transmitting with UARTD0. This ISR is only defined if the macro ENABLE_UART_D0 is defined.
	ISR (USARTD1_RXC_vect)
	Interrupt Service Routine for receiving with UARTD1. This ISR is only defined if the macro ENABLE_UART_D1 is defined.
	ISR (USARTD1_DRE_vect)
	Interrupt Service Routine for transmitting with UARTD1. This ISR is only defined if the macro ENABLE_UART_D1 is defined.
	ISR (USARTE0_RXC_vect)
	Interrupt Service Routine for receiving with UARTE0. This ISR is only defined if the macro ENABLE_UART_E0 is defined.
	ISR (USARTE0_DRE_vect)
	Interrupt Service Routine for transmitting with UARTE0. This ISR is only defined if the macro ENABLE_UART_E0 is defined.
	ISR (USARTE1_RXC_vect)
	Interrupt Service Routine for receiving with UARTE1. This ISR is only defined if the macro ENABLE_UART_E1 is defined.
	ISR (USARTE1_DRE_vect)
	Interrupt Service Routine for transmitting with UARTE1. This ISR is only defined if the macro ENABLE_UART_E1 is defined.
	ISR (USARTF0_RXC_vect)
	Interrupt Service Routine for receiving with UARTF0. This ISR is only defined if the macro ENABLE_UART_F0 is defined.
	ISR (USARTF0_DRE_vect)
	Interrupt Service Routine for transmitting with UARTF0. This ISR is only defined if the macro ENABLE_UART_F0 is defined.
	ISR (USARTF1_RXC_vect)
	Interrupt Service Routine for receiving with UARTF1. This ISR is only defined if the macro ENABLE_UART_F1 is defined.
	ISR (USARTF1_DRE_vect)
	Interrupt Service Routine for transmitting with UARTF1. This ISR is only defined if the macro ENABLE_UART_F1 is defined.

Variables
USART_data_t	uartC0
	Global declaration uart with databuffers for UARTC0. This variable is only defined if the macro ENABLE_UART_C0 is defined.
USART_data_t	uartC1
	Global declaration uart with databuffers for UARTC1. This variable is only defined if the macro ENABLE_UART_C0 is defined.
USART_data_t	uartD0
	Global declaration uart with databuffers for UARTD0. This variable is only defined if the macro ENABLE_UART_D0 is defined.
USART_data_t	uartD1
	Global declaration uart with databuffers for UARTD1. This variable is only defined if the macro ENABLE_UART_D1 is defined.
USART_data_t	uartE0
	Global declaration uart with databuffers for UARTE0. This variable is only defined if the macro ENABLE_UART_E0 is defined.
USART_data_t	uartE1
	Global declaration uart with databuffers for UARTE1. This variable is only defined if the macro ENABLE_UART_E1 is defined.
USART_data_t	uartF0
	Global declaration uart with databuffers for UARTF0. This variable is only defined if the macro ENABLE_UART_F0 is defined.
USART_data_t	uartF1
	Global declaration uart with databuffers for UARTF1. This variable is only defined if the macro ENABLE_UART_F1 is defined.

Detailed Description

Wrapper for UART-driver of Atmel for Xmega.

Author

Wim Dolman (w.e.dolman@hva.nl)

Date

29-11-2013

Version

1.1

The files uart.c and uart.h uses the UART-driver uart_driver.c and uart_driver.h from Atmel, see http://www.atmel.com/Images/doc8049.pdf and http://www.atmel.com/Images/AVR1307.zip.

It is a kind of wrapper with the same style as the UART-drivers from Peter Fleury (http://jump.to/fleury) for the ATmega.

For every buffered UART we need two Interrupt Service Routine: one for receiving and one for transmitting For each UART there is a condition. If the condition is true the two ISR's will be compiled, else they will be skipped. The condition for UART uart_id depends on a macro ENABLE_UART_uart_id

To use, for example, UARTC1 define in the code just before including uart.h a macro ENABLE_UART_C1:

   #define ENABLE_UART_C1 1
   #include <uart.h>

Note

An AVR-project can use multiple UART's. One shoud take care that in different source files there are no multiple ENABLE_UART_uart_id definitions for the same UART.

Function Documentation

uint16_t calc_bsel	(	uint32_t	f_cpu,
		uint32_t	baud,
		int8_t	scale,
		uint8_t	clk2x
	)

Calculates the baud rate value BSEL.

Parameters

f_cpu	system clock (F_CPU)
baud	desired baud rate
scale	scale factor (BSCALE)
clk2x	clock speed double (1 for double, 0 for no double)

It calculates the baud selection value BSEL from the system clock, the baud rate, the scale factor and a boolean for clock doubling.

The formula to calculate BSEL is:

N is a factor which is 16 with no clock doubling and 8 with clock doubling

Returns

the calculated BSEL

void init_uart	(	USART_data_t *	uart,
		USART_t *	usart,
		uint32_t	f_cpu,
		uint32_t	baud,
		uint8_t	clk2x
	)

Initializes the UART.

Parameters

uart	pointer to a UART datastructure with buffers
usart	pointer to a UART datastructure
f_cpu	system clock (F_CPU)
baud	desired baud rate
clk2x	clock speed double (1 for double, 0 for no double)

It calculates the scale factor BSCALE and the baud selection value BSEL. It selects what USART module to use and it initializes receive and transmit buffer. It initializes the USART module and sets the direction of TXD and RXD pin. The interrupt levels of the DRE interrupt function and the RXC interrupt function are both set to a low level.

Returns

void

void init_uart_levels	(	USART_data_t *	uart,
		USART_t *	usart,
		uint32_t	f_cpu,
		uint32_t	baud,
		uint8_t	clk2x,
		USART_RXCINTLVL_t	rxcIntLevel,
		USART_DREINTLVL_t	dreIntLevel
	)

Initializes the UART.

Parameters

uart	pointer to a UART datastructure with buffers
usart	pointer to a UART datastructure (UART module)
f_cpu	system clock (F_CPU)
baud	desired baud rate
clk2x	clock speed double (1 for double, 0 for no double)
rxcIntLevel	RXC interrupt level
dreIntLevel	DRE interrupt level

It calculates the scale factor BSCALE and the baud selection value BSEL. It selects what USART module to use and it initializes receive and transmit buffer. It initializes the USART module and sets the direction of TXD and RXD pin. The interrupt level of the DRE interrupt function and the RXC interrupt function are set to dreIntLevel and rxcIntLevel.

Returns

void

void set_usart_txrx_direction

(

USART_t *

usart

)

Set direction for the transmit and receive pin.

Parameters

usart

pointer to UART datastructure (UART module)

Returns

void

uint16_t uart_getc

(

USART_data_t *

uart

)

Get a byte from the circular receive buffer.

Parameters

uart	pointer to UART datastructure with buffers

Returns

received byte from circulair buffer (low byte) or UART_NO_DATA if buffer is empty

void uart_putc	(	USART_data_t *	uart,
		uint8_t	data
	)

Write a byte to the circular transmit buffer.

Parameters

uart	pointer to UART datastructure with buffers
data	byte to be written

Returns

void

void uart_puts	(	USART_data_t *	uart,
		char *	s
	)

Write a string to the circulair transmit buffer.

Parameters

uart	pointer to UART datastructure with buffers
s	pointer to string to be written

Returns

void