Universal Synchronous Asynchronous

Receiver Transmitter (USART). More...

Macros
#define	HIGH_FRQ_SAMPLE_DIV   16
#define	ISO7816_T_0   0
#define	ISO7816_T_1   1
#define	LOW_FRQ_SAMPLE_DIV   8
#define	MAX_CD_VALUE   US_BRGR_CD_Msk
#define	MAX_TRAN_GUARD_TIME   US_TTGR_TG_Msk
#define	MIN_CD_VALUE   0x01
#define	MIN_CD_VALUE_SPI   0x04
#define	US_WPMR_WPKEY_PASSWD   US_WPMR_WPKEY(0x555341U)
#define	USART_PARITY_ERROR   5

Functions
void	usart_disable_interrupt (Usart *p_usart, uint32_t ul_sources)
	Disable USART interrupts.
void	usart_disable_rx (Usart *p_usart)
	Disable USART receiver.
void	usart_disable_tx (Usart *p_usart)
	Disable USART transmitter.
void	usart_disable_writeprotect (Usart *p_usart)
	Disable write protect of USART registers.
void	usart_drive_DTR_pin_high (Usart *p_usart)
	Drive the pin DTR to 1.
void	usart_drive_DTR_pin_low (Usart *p_usart)
	Drive the pin DTR to 0.
void	usart_drive_RTS_pin_high (Usart *p_usart)
	Drive the pin RTS to 1.
void	usart_drive_RTS_pin_low (Usart *p_usart)
	Drive the pin RTS to 0.
void	usart_enable_interrupt (Usart *p_usart, uint32_t ul_sources)
	Enable USART interrupts.
void	usart_enable_rx (Usart *p_usart)
	Enable USART receiver.
void	usart_enable_tx (Usart *p_usart)
	Enable USART transmitter.
void	usart_enable_writeprotect (Usart *p_usart)
	Enable write protect of USART registers.
uint8_t	usart_get_error_number (Usart *p_usart)
	Get the total number of errors that occur during an ISO7816 transfer.
uint32_t	usart_get_interrupt_mask (Usart *p_usart)
	Read USART interrupt mask.
Pdc *	usart_get_pdc_base (Usart *p_usart)
	Get USART PDC base address.
uint32_t	usart_get_status (Usart *p_usart)
	Get current status.
uint32_t	usart_get_writeprotect_status (Usart *p_usart)
	Get write protect status.
uint32_t	usart_getchar (Usart *p_usart, uint32_t *c)
	Read from USART Receive Holding Register.
uint32_t	usart_init_hw_handshaking (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in hardware handshaking mode.
uint32_t	usart_init_irda (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in IrDA mode.
uint32_t	usart_init_iso7816 (Usart *p_usart, const usart_iso7816_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in ISO7816 mode.
uint32_t	usart_init_modem (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in modem mode.
uint32_t	usart_init_rs232 (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in RS232 mode.
uint32_t	usart_init_rs485 (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in RS485 mode.
uint32_t	usart_init_spi_master (Usart *p_usart, const usart_spi_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in SPI mode and act as a master.
uint32_t	usart_init_spi_slave (Usart *p_usart, const usart_spi_opt_t *p_usart_opt)
	Configure USART to work in SPI mode and act as a slave.
uint32_t	usart_init_sync_master (Usart *p_usart, const sam_usart_opt_t *p_usart_opt, uint32_t ul_mck)
	Configure USART to work in SYNC mode and act as a master.
uint32_t	usart_init_sync_slave (Usart *p_usart, const sam_usart_opt_t *p_usart_opt)
	Configure USART to work in SYNC mode and act as a slave.
uint32_t	usart_is_rx_buf_end (Usart *p_usart)
	Check if one receive buffer is filled.
uint32_t	usart_is_rx_buf_full (Usart *p_usart)
	Check if both receive buffers are full.
uint32_t	usart_is_rx_ready (Usart *p_usart)
	Check if the received data are ready.
uint32_t	usart_is_tx_buf_empty (Usart *p_usart)
	Check if both transmit buffers are empty.
uint32_t	usart_is_tx_buf_end (Usart *p_usart)
	Check if one transmit buffer is empty.
uint32_t	usart_is_tx_empty (Usart *p_usart)
	Check if Transmit Holding Register is empty.
uint32_t	usart_is_tx_ready (Usart *p_usart)
	Check if Transmit is Ready.
void	usart_man_disable_drift_compensation (Usart *p_usart)
	Disable drift compensation.
void	usart_man_enable_drift_compensation (Usart *p_usart)
	Enable drift compensation.
void	usart_man_set_rx_polarity (Usart *p_usart, uint8_t uc_polarity)
	Configure the receiver Manchester polarity when the Manchester encode/decode is enabled.
void	usart_man_set_rx_pre_len (Usart *p_usart, uint8_t uc_len)
	Configure the detected receiver preamble length when the Manchester encode/decode is enabled.
void	usart_man_set_rx_pre_pattern (Usart *p_usart, uint8_t uc_pattern)
	Configure the detected receiver preamble pattern when the Manchester encode/decode is enabled, which should be 0 ~ 3.
void	usart_man_set_tx_polarity (Usart *p_usart, uint8_t uc_polarity)
	Configure the transmitter Manchester polarity when the Manchester encode/decode is enabled.
void	usart_man_set_tx_pre_len (Usart *p_usart, uint8_t uc_len)
	Configure the transmitter preamble length when the Manchester encode/decode is enabled.
void	usart_man_set_tx_pre_pattern (Usart *p_usart, uint8_t uc_pattern)
	Configure the transmitter preamble pattern when the Manchester encode/decode is enabled, which should be 0 ~ 3.
uint32_t	usart_putchar (Usart *p_usart, uint32_t c)
	Write to USART Transmit Holding Register.
uint32_t	usart_read (Usart *p_usart, uint32_t *c)
	Read from USART Receive Holding Register.
void	usart_reset (Usart *p_usart)
	Reset the USART and disable TX and RX.
void	usart_reset_iterations (Usart *p_usart)
	Reset the ITERATION in US_CSR when the ISO7816 mode is enabled.
void	usart_reset_nack (Usart *p_usart)
	Reset NACK in US_CSR.
void	usart_reset_rx (Usart *p_usart)
	Immediately stop and disable USART receiver.
void	usart_reset_status (Usart *p_usart)
	Reset status bits (PARE, OVER, MANERR, UNRE and PXBRK in US_CSR).
void	usart_reset_tx (Usart *p_usart)
	Immediately stop and disable USART transmitter.
void	usart_restart_rx_timeout (Usart *p_usart)
	Restart the receive timeout.
uint32_t	usart_send_address (Usart *p_usart, uint32_t ul_addr)
	In Multidrop mode only, the next character written to the US_THR is sent with the address bit set.
uint32_t	usart_set_async_baudrate (Usart *p_usart, uint32_t baudrate, uint32_t ul_mck)
	Calculate a clock divider(CD) and a fractional part (FP) for the USART asynchronous modes to generate a baudrate as close as possible to the baudrate set point.
static uint32_t	usart_set_iso7816_clock (Usart *p_usart, uint32_t clock, uint32_t ul_mck)
	Calculate a clock divider (CD) for the USART ISO7816 mode to generate an ISO7816 clock as close as possible to the clock set point.
void	usart_set_rx_timeout (Usart *p_usart, uint32_t timeout)
	Configure the receive timeout register.
static uint32_t	usart_set_spi_master_baudrate (Usart *p_usart, uint32_t baudrate, uint32_t ul_mck)
	Calculate a clock divider (CD) for the USART SPI master mode to generate a baud rate as close as possible to the baud rate set point.
static void	usart_set_spi_slave_baudrate (Usart *p_usart)
	Select the SCK pin as the source of baudrate for the USART SPI slave mode.
static uint32_t	usart_set_sync_master_baudrate (Usart *p_usart, uint32_t baudrate, uint32_t ul_mck)
	Calculate a clock divider for the USART synchronous master modes to generate a baudrate as close as possible to the baudrate set point.
static void	usart_set_sync_slave_baudrate (Usart *p_usart)
	Select the SCK pin as the source of baud rate for the USART synchronous slave modes.
void	usart_set_tx_timeguard (Usart *p_usart, uint32_t timeguard)
	Configure the transmit timeguard register.
void	usart_spi_force_chip_select (Usart *p_usart)
	Drive the slave select line NSS (RTS pin) to 0 in SPI master mode.
void	usart_spi_release_chip_select (Usart *p_usart)
	Drive the slave select line NSS (RTS pin) to 1 in SPI master mode.
void	usart_start_rx_timeout (Usart *p_usart)
	Start waiting for a character before clocking the timeout count.
void	usart_start_tx_break (Usart *p_usart)
	Start transmission of a break.
void	usart_stop_tx_break (Usart *p_usart)
	Stop transmission of a break.
uint32_t	usart_write (Usart *p_usart, uint32_t c)
	Write to USART Transmit Holding Register.
void	usart_write_line (Usart *p_usart, const char *string)
	Write one-line string through USART.

Detailed Description

Receiver Transmitter (USART).

The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one full duplex universal synchronous asynchronous serial link. Data frame format is widely programmable (data length, parity, number of stop bits) to support a maximum of standards. The receiver implements parity error, framing error and overrun error detection. The receiver time-out enables handling variable-length frames and the transmitter timeguard facilitates communications with slow remote devices. Multidrop communications are also supported through address bit handling in reception and transmission. The driver supports the following modes: RS232, RS485, SPI, IrDA, ISO7816, MODEM, Hardware handshaking and LIN.

Macro Definition Documentation

HIGH_FRQ_SAMPLE_DIV

#define HIGH_FRQ_SAMPLE_DIV   16

Definition at line 81 of file usart.c.

Referenced by usart_set_async_baudrate().

ISO7816_T_0

#define ISO7816_T_0   0

Definition at line 91 of file usart.c.

Referenced by usart_init_iso7816().

ISO7816_T_1

#define ISO7816_T_1   1

Definition at line 92 of file usart.c.

Referenced by usart_init_iso7816().

LOW_FRQ_SAMPLE_DIV

#define LOW_FRQ_SAMPLE_DIV   8

Definition at line 82 of file usart.c.

Referenced by usart_set_async_baudrate().

MAX_CD_VALUE

#define MAX_CD_VALUE   US_BRGR_CD_Msk

Definition at line 78 of file usart.c.

Referenced by usart_set_async_baudrate(), usart_set_iso7816_clock(), usart_set_spi_master_baudrate(), and usart_set_sync_master_baudrate().

MAX_TRAN_GUARD_TIME

#define MAX_TRAN_GUARD_TIME   US_TTGR_TG_Msk

Definition at line 85 of file usart.c.

MIN_CD_VALUE

#define MIN_CD_VALUE   0x01

Definition at line 76 of file usart.c.

MIN_CD_VALUE_SPI

#define MIN_CD_VALUE_SPI   0x04

Definition at line 77 of file usart.c.

US_WPMR_WPKEY_PASSWD

#define US_WPMR_WPKEY_PASSWD   US_WPMR_WPKEY(0x555341U)

Definition at line 68 of file usart.c.

Referenced by usart_disable_writeprotect(), and usart_enable_writeprotect().

USART_PARITY_ERROR

#define USART_PARITY_ERROR   5

Definition at line 88 of file usart.c.

Function Documentation

usart_disable_interrupt()

void usart_disable_interrupt	(	Usart *	p_usart,
		uint32_t	ul_sources )

Disable USART interrupts.

Parameters

p_usart	Pointer to a USART peripheral.
ul_sources	Interrupt sources bit map.

Definition at line 1480 of file usart.c.

{
    p_usart->US_IDR = ul_sources;
}

References Usart::US_IDR.

usart_disable_rx()

void usart_disable_rx

(

Usart *

p_usart

)

Disable USART receiver.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1436 of file usart.c.

{
    p_usart->US_CR = US_CR_RXDIS;
}

References Usart::US_CR, and US_CR_RXDIS.

usart_disable_tx()

void usart_disable_tx

(

Usart *

p_usart

)

Disable USART transmitter.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1394 of file usart.c.

{
    p_usart->US_CR = US_CR_TXDIS;
}

References Usart::US_CR, and US_CR_TXDIS.

usart_disable_writeprotect()

void usart_disable_writeprotect

(

Usart *

p_usart

)

Disable write protect of USART registers.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1907 of file usart.c.

{
    p_usart->US_WPMR = US_WPMR_WPKEY_PASSWD;
}

References Usart::US_WPMR, and US_WPMR_WPKEY_PASSWD.

Referenced by usart_reset().

usart_drive_DTR_pin_high()

void usart_drive_DTR_pin_high

(

Usart *

p_usart

)

Drive the pin DTR to 1.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1602 of file usart.c.

{
    p_usart->US_CR = US_CR_DTRDIS;
}

References Usart::US_CR, and US_CR_DTRDIS.

Referenced by usart_reset().

usart_drive_DTR_pin_low()

void usart_drive_DTR_pin_low

(

Usart *

p_usart

)

Drive the pin DTR to 0.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1592 of file usart.c.

{
    p_usart->US_CR = US_CR_DTREN;
}

References Usart::US_CR, and US_CR_DTREN.

usart_drive_RTS_pin_high()

void usart_drive_RTS_pin_high

(

Usart *

p_usart

)

Drive the pin RTS to 1.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1624 of file usart.c.

{
    p_usart->US_CR = US_CR_RTSDIS;
}

References Usart::US_CR, and US_CR_RTSDIS.

Referenced by usart_reset().

usart_drive_RTS_pin_low()

void usart_drive_RTS_pin_low

(

Usart *

p_usart

)

Drive the pin RTS to 0.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1614 of file usart.c.

{
    p_usart->US_CR = US_CR_RTSEN;
}

References Usart::US_CR, and US_CR_RTSEN.

usart_enable_interrupt()

void usart_enable_interrupt	(	Usart *	p_usart,
		uint32_t	ul_sources )

Enable USART interrupts.

Parameters

p_usart	Pointer to a USART peripheral.
ul_sources	Interrupt sources bit map.

Definition at line 1469 of file usart.c.

{
    p_usart->US_IER = ul_sources;
}

References Usart::US_IER.

usart_enable_rx()

void usart_enable_rx

(

Usart *

p_usart

)

Enable USART receiver.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1426 of file usart.c.

{
    p_usart->US_CR = US_CR_RXEN;
}

References Usart::US_CR, and US_CR_RXEN.

Referenced by usart_serial_init().

usart_enable_tx()

void usart_enable_tx

(

Usart *

p_usart

)

Enable USART transmitter.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1384 of file usart.c.

{
    p_usart->US_CR = US_CR_TXEN;
}

References Usart::US_CR, and US_CR_TXEN.

Referenced by usart_serial_init().

usart_enable_writeprotect()

void usart_enable_writeprotect

(

Usart *

p_usart

)

Enable write protect of USART registers.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1897 of file usart.c.

{
    p_usart->US_WPMR = US_WPMR_WPEN | US_WPMR_WPKEY_PASSWD;
}

References Usart::US_WPMR, US_WPMR_WPEN, and US_WPMR_WPKEY_PASSWD.

usart_get_error_number()

uint8_t usart_get_error_number

(

Usart *

p_usart

)

Get the total number of errors that occur during an ISO7816 transfer.

Parameters

p_usart

Pointer to a USART instance.

Returns

The number of errors that occurred.

Definition at line 699 of file usart.c.

{
    return (p_usart->US_NER & US_NER_NB_ERRORS_Msk);
}

References Usart::US_NER, and US_NER_NB_ERRORS_Msk.

usart_get_interrupt_mask()

uint32_t usart_get_interrupt_mask

(

Usart *

p_usart

)

Read USART interrupt mask.

Parameters

p_usart

Pointer to a USART peripheral.

Returns

The interrupt mask value.

Definition at line 1492 of file usart.c.

{
    return p_usart->US_IMR;
}

References Usart::US_IMR.

usart_get_pdc_base()

Pdc * usart_get_pdc_base

(

Usart *

p_usart

)

Get USART PDC base address.

Parameters

p_usart

Pointer to a UART instance.

Returns

USART PDC registers base for PDC driver to access.

Definition at line 1827 of file usart.c.

{
    Pdc *p_pdc_base;
 
    p_pdc_base = (Pdc *)NULL;
 
#ifdef PDC_USART
    if (p_usart == USART) {
        p_pdc_base = PDC_USART;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART0
    if (p_usart == USART0) {
        p_pdc_base = PDC_USART0;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART1
    else if (p_usart == USART1) {
        p_pdc_base = PDC_USART1;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART2
    else if (p_usart == USART2) {
        p_pdc_base = PDC_USART2;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART3
    else if (p_usart == USART3) {
        p_pdc_base = PDC_USART3;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART4
    else if (p_usart == USART4) {
        p_pdc_base = PDC_USART4;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART5
    else if (p_usart == USART5) {
        p_pdc_base = PDC_USART5;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART6
    else if (p_usart == USART6) {
        p_pdc_base = PDC_USART6;
        return p_pdc_base;
    }
#endif
#ifdef PDC_USART7
    else if (p_usart == USART7) {
        p_pdc_base = PDC_USART7;
        return p_pdc_base;
    }
#endif
 
    return p_pdc_base;
}

References PDC_USART0, PDC_USART1, USART0, and USART1.

usart_get_status()

uint32_t usart_get_status

(

Usart *

p_usart

)

Get current status.

Parameters

p_usart

Pointer to a USART instance.

Returns

The current USART status.

Definition at line 1504 of file usart.c.

{
    return p_usart->US_CSR;
}

References Usart::US_CSR.

usart_get_writeprotect_status()

uint32_t usart_get_writeprotect_status

(

Usart *

p_usart

)

Get write protect status.

Parameters

p_usart

Pointer to a USART instance.

Returns

0 if no write protect violation occurred, or 16-bit write protect violation source.

Definition at line 1920 of file usart.c.

{
    uint32_t reg_value;
 
    reg_value = p_usart->US_WPSR;
    if (reg_value & US_WPSR_WPVS) {
        return (reg_value & US_WPSR_WPVSRC_Msk) >> US_WPSR_WPVSRC_Pos;
    } else {
        return 0;
    }
}

References Usart::US_WPSR, US_WPSR_WPVS, US_WPSR_WPVSRC_Msk, and US_WPSR_WPVSRC_Pos.

usart_getchar()

uint32_t usart_getchar	(	Usart *	p_usart,
		uint32_t *	c )

Read from USART Receive Holding Register.

Before reading user should check if rx is ready.

Parameters

p_usart	Pointer to a USART instance.
c	Pointer where the one-byte received data will be stored.

Return values

0	Data has been received.
1	on failure.

Definition at line 1781 of file usart.c.

{
    /* Wait until it's not empty or timeout has reached. */
    while (!(p_usart->US_CSR & US_CSR_RXRDY)) {
    }
 
    /* Read character */
    *c = p_usart->US_RHR & US_RHR_RXCHR_Msk;
 
    return 0;
}

References Usart::US_CSR, US_CSR_RXRDY, Usart::US_RHR, and US_RHR_RXCHR_Msk.

usart_init_hw_handshaking()

uint32_t usart_init_hw_handshaking	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in hardware handshaking mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 313 of file usart.c.

{
    /* Initialize the USART as standard RS232. */
    if (usart_init_rs232(p_usart, p_usart_opt, ul_mck)) {
        return 1;
    }
 
    /* Set hardware handshaking mode. */
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USART_MODE_Msk) |
            US_MR_USART_MODE_HW_HANDSHAKING;
 
    return 0;
}

References Usart::US_MR, US_MR_USART_MODE_HW_HANDSHAKING, US_MR_USART_MODE_Msk, and usart_init_rs232().

usart_init_irda()

uint32_t usart_init_irda	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in IrDA mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 490 of file usart.c.

{
    /* Initialize the USART as standard RS232. */
    if (usart_init_rs232(p_usart, p_usart_opt, ul_mck)) {
        return 1;
    }
 
    /* Set IrDA filter. */
    p_usart->US_IF = p_usart_opt->irda_filter;
 
    /* Set IrDA mode. */
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USART_MODE_Msk) |
            US_MR_USART_MODE_IRDA;
 
    return 0;
}

References sam_usart_opt_t::irda_filter, Usart::US_IF, Usart::US_MR, US_MR_USART_MODE_IRDA, US_MR_USART_MODE_Msk, and usart_init_rs232().

usart_init_iso7816()

uint32_t usart_init_iso7816	(	Usart *	p_usart,
		const usart_iso7816_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in ISO7816 mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 557 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
 
    /* Check whether the input values are legal. */
    if (!p_usart_opt || ((p_usart_opt->parity_type != US_MR_PAR_EVEN) &&
            (p_usart_opt->parity_type != US_MR_PAR_ODD))) {
        return 1;
    }
 
    if (p_usart_opt->protocol_type == ISO7816_T_0) {
        ul_reg_val |= US_MR_USART_MODE_IS07816_T_0 | US_MR_NBSTOP_2_BIT |
                (p_usart_opt->max_iterations << US_MR_MAX_ITERATION_Pos);
 
        if (p_usart_opt->bit_order) {
            ul_reg_val |= US_MR_MSBF;
        }
    } else if (p_usart_opt->protocol_type == ISO7816_T_1) {
        /*
         * Only LSBF is used in the T=1 protocol, and max_iterations field
         * is only used in T=0 mode.
         */
        if (p_usart_opt->bit_order || p_usart_opt->max_iterations) {
            return 1;
        }
 
        /* Set USART mode to ISO7816, T=1, and always uses 1 stop bit. */
        ul_reg_val |= US_MR_USART_MODE_IS07816_T_1 | US_MR_NBSTOP_1_BIT;
    } else {
        return 1;
    }
 
    /* Set up the baudrate. */
    if (usart_set_iso7816_clock(p_usart, p_usart_opt->iso7816_hz, ul_mck)) {
        return 1;
    }
 
    /* Set FIDI register: bit rate = iso7816_hz / fidi_ratio. */
    p_usart->US_FIDI = p_usart_opt->fidi_ratio;
 
    /* Set ISO7816 parity type in the MODE register. */
    ul_reg_val |= p_usart_opt->parity_type;
 
    if (p_usart_opt->inhibit_nack) {
        ul_reg_val |= US_MR_INACK;
    }
    if (p_usart_opt->dis_suc_nack) {
        ul_reg_val |= US_MR_DSNACK;
    }
 
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References usart_iso7816_opt_t::bit_order, usart_iso7816_opt_t::dis_suc_nack, usart_iso7816_opt_t::fidi_ratio, usart_iso7816_opt_t::inhibit_nack, usart_iso7816_opt_t::iso7816_hz, ISO7816_T_0, ISO7816_T_1, usart_iso7816_opt_t::max_iterations, usart_iso7816_opt_t::parity_type, usart_iso7816_opt_t::protocol_type, Usart::US_FIDI, Usart::US_MR, US_MR_DSNACK, US_MR_INACK, US_MR_MAX_ITERATION_Pos, US_MR_MSBF, US_MR_NBSTOP_1_BIT, US_MR_NBSTOP_2_BIT, US_MR_PAR_EVEN, US_MR_PAR_ODD, US_MR_USART_MODE_IS07816_T_0, US_MR_USART_MODE_IS07816_T_1, usart_reset(), and usart_set_iso7816_clock().

usart_init_modem()

uint32_t usart_init_modem	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in modem mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 342 of file usart.c.

{
    /*
     * SAM3S, SAM4S and SAM4E series support MODEM mode only on USART1,
     * SAM3U and SAM4L series support MODEM mode only on USART0.
     */
#if (SAM3S || SAM4S || SAM4E)
#ifdef USART1
    if (p_usart != USART1) {
        return 1;
    }
#endif
#elif (SAM3U || SAM4L)
    if (p_usart != USART0) {
        return 1;
    }
#endif
 
    /* Initialize the USART as standard RS232. */
    if (usart_init_rs232(p_usart, p_usart_opt, ul_mck)) {
        return 1;
    }
 
    /* Set MODEM mode. */
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USART_MODE_Msk) |
            US_MR_USART_MODE_MODEM;
 
    return 0;
}

References Usart::US_MR, US_MR_USART_MODE_MODEM, US_MR_USART_MODE_Msk, USART0, USART1, and usart_init_rs232().

usart_init_rs232()

uint32_t usart_init_rs232	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in RS232 mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 274 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
    /* Check whether the input values are legal. */
    if (!p_usart_opt || usart_set_async_baudrate(p_usart,
            p_usart_opt->baudrate, ul_mck)) {
        return 1;
    }
 
    /* Configure the USART option. */
    ul_reg_val |= p_usart_opt->char_length | p_usart_opt->parity_type |
            p_usart_opt->channel_mode | p_usart_opt->stop_bits;
 
    /* Configure the USART mode as normal mode. */
    ul_reg_val |= US_MR_USART_MODE_NORMAL;
 
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References sam_usart_opt_t::baudrate, sam_usart_opt_t::channel_mode, sam_usart_opt_t::char_length, sam_usart_opt_t::parity_type, sam_usart_opt_t::stop_bits, Usart::US_MR, US_MR_USART_MODE_NORMAL, usart_reset(), and usart_set_async_baudrate().

Referenced by usart_init_hw_handshaking(), usart_init_irda(), usart_init_modem(), usart_init_rs485(), and usart_serial_init().

usart_init_rs485()

uint32_t usart_init_rs485	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in RS485 mode.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 462 of file usart.c.

{
    /* Initialize the USART as standard RS232. */
    if (usart_init_rs232(p_usart, p_usart_opt, ul_mck)) {
        return 1;
    }
 
    /* Set RS485 mode. */
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USART_MODE_Msk) |
            US_MR_USART_MODE_RS485;
 
    return 0;
}

References Usart::US_MR, US_MR_USART_MODE_Msk, US_MR_USART_MODE_RS485, and usart_init_rs232().

usart_init_spi_master()

uint32_t usart_init_spi_master	(	Usart *	p_usart,
		const usart_spi_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in SPI mode and act as a master.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 718 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
    /* Check whether the input values are legal. */
    if (!p_usart_opt || (p_usart_opt->spi_mode > SPI_MODE_3) ||
            usart_set_spi_master_baudrate(p_usart, p_usart_opt->baudrate,
            ul_mck)) {
        return 1;
    }
 
    /* Configure the character length bit in MR register. */
    ul_reg_val |= p_usart_opt->char_length;
 
    /* Set SPI master mode and channel mode. */
    ul_reg_val |= US_MR_USART_MODE_SPI_MASTER | US_MR_CLKO |
            p_usart_opt->channel_mode;
 
    switch (p_usart_opt->spi_mode) {
    case SPI_MODE_0:
        ul_reg_val |= US_MR_CPHA;
        ul_reg_val &= ~US_MR_CPOL;
        break;
 
    case SPI_MODE_1:
        ul_reg_val &= ~US_MR_CPHA;
        ul_reg_val &= ~US_MR_CPOL;
        break;
 
    case SPI_MODE_2:
        ul_reg_val |= US_MR_CPHA;
        ul_reg_val |= US_MR_CPOL;
        break;
 
    case SPI_MODE_3:
        ul_reg_val &= ~US_MR_CPHA;
        ul_reg_val |= US_MR_CPOL;
        break;
 
    default:
        break;
    }
 
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References usart_spi_opt_t::baudrate, usart_spi_opt_t::channel_mode, usart_spi_opt_t::char_length, usart_spi_opt_t::spi_mode, SPI_MODE_0, SPI_MODE_1, SPI_MODE_2, SPI_MODE_3, Usart::US_MR, US_MR_CLKO, US_MR_CPHA, US_MR_CPOL, US_MR_USART_MODE_SPI_MASTER, usart_reset(), and usart_set_spi_master_baudrate().

usart_init_spi_slave()

uint32_t usart_init_spi_slave	(	Usart *	p_usart,
		const usart_spi_opt_t *	p_usart_opt )

Configure USART to work in SPI mode and act as a slave.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.

Return values

0	on success.
1	on failure.

Definition at line 782 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
    usart_set_spi_slave_baudrate(p_usart);
 
    /* Check whether the input values are legal. */
    if (!p_usart_opt || p_usart_opt->spi_mode > SPI_MODE_3) {
        return 1;
    }
 
    /* Configure the character length bit in MR register. */
    ul_reg_val |= p_usart_opt->char_length;
 
    /* Set SPI slave mode and channel mode. */
    ul_reg_val |= US_MR_USART_MODE_SPI_SLAVE | p_usart_opt->channel_mode;
 
    switch (p_usart_opt->spi_mode) {
    case SPI_MODE_0:
        ul_reg_val |= US_MR_CPHA;
        ul_reg_val &= ~US_MR_CPOL;
        break;
 
    case SPI_MODE_1:
        ul_reg_val &= ~US_MR_CPHA;
        ul_reg_val &= ~US_MR_CPOL;
        break;
 
    case SPI_MODE_2:
        ul_reg_val |= US_MR_CPHA;
        ul_reg_val |= US_MR_CPOL;
        break;
 
    case SPI_MODE_3:
        ul_reg_val |= US_MR_CPOL;
        ul_reg_val &= ~US_MR_CPHA;
        break;
 
    default:
        break;
    }
 
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References usart_spi_opt_t::channel_mode, usart_spi_opt_t::char_length, usart_spi_opt_t::spi_mode, SPI_MODE_0, SPI_MODE_1, SPI_MODE_2, SPI_MODE_3, Usart::US_MR, US_MR_CPHA, US_MR_CPOL, US_MR_USART_MODE_SPI_SLAVE, usart_reset(), and usart_set_spi_slave_baudrate().

usart_init_sync_master()

uint32_t usart_init_sync_master	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt,
		uint32_t	ul_mck )

Configure USART to work in SYNC mode and act as a master.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.
ul_mck	USART module input clock frequency.

Return values

0	on success.
1	on failure.

Definition at line 386 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
    /* Check whether the input values are legal. */
    if (!p_usart_opt || usart_set_sync_master_baudrate(p_usart,
            p_usart_opt->baudrate, ul_mck)) {
        return 1;
    }
 
    /* Configure the USART option. */
    ul_reg_val |= p_usart_opt->char_length | p_usart_opt->parity_type |
            p_usart_opt->channel_mode | p_usart_opt->stop_bits;
 
    /* Set normal mode and output clock as synchronous master. */
    ul_reg_val |= US_MR_USART_MODE_NORMAL | US_MR_CLKO;
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References sam_usart_opt_t::baudrate, sam_usart_opt_t::channel_mode, sam_usart_opt_t::char_length, sam_usart_opt_t::parity_type, sam_usart_opt_t::stop_bits, Usart::US_MR, US_MR_CLKO, US_MR_USART_MODE_NORMAL, usart_reset(), and usart_set_sync_master_baudrate().

usart_init_sync_slave()

uint32_t usart_init_sync_slave	(	Usart *	p_usart,
		const sam_usart_opt_t *	p_usart_opt )

Configure USART to work in SYNC mode and act as a slave.

Note

By default, the transmitter and receiver aren't enabled.

Parameters

p_usart	Pointer to a USART instance.
p_usart_opt	Pointer to sam_usart_opt_t instance.

Return values

0	on success.
1	on failure.

Definition at line 423 of file usart.c.

{
    static uint32_t ul_reg_val;
 
    /* Reset the USART and shut down TX and RX. */
    usart_reset(p_usart);
 
    ul_reg_val = 0;
    usart_set_sync_slave_baudrate(p_usart);
 
    /* Check whether the input values are legal. */
    if (!p_usart_opt) {
        return 1;
    }
 
    /* Configure the USART option. */
    ul_reg_val |= p_usart_opt->char_length | p_usart_opt->parity_type |
            p_usart_opt->channel_mode | p_usart_opt->stop_bits;
 
    /* Set normal mode. */
    ul_reg_val |= US_MR_USART_MODE_NORMAL;
    p_usart->US_MR |= ul_reg_val;
 
    return 0;
}

References sam_usart_opt_t::channel_mode, sam_usart_opt_t::char_length, sam_usart_opt_t::parity_type, sam_usart_opt_t::stop_bits, Usart::US_MR, US_MR_USART_MODE_NORMAL, usart_reset(), and usart_set_sync_slave_baudrate().

usart_is_rx_buf_end()

uint32_t usart_is_rx_buf_end

(

Usart *

p_usart

)

Check if one receive buffer is filled.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Receive is complete.
0	Receive is still pending.

Definition at line 660 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_ENDRX) > 0;
}

References Usart::US_CSR, and US_CSR_ENDRX.

usart_is_rx_buf_full()

uint32_t usart_is_rx_buf_full

(

Usart *

p_usart

)

Check if both receive buffers are full.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Receive buffers are full.
0	Receive buffers are not full.

Definition at line 646 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_RXBUFF) > 0;
}

References Usart::US_CSR, and US_CSR_RXBUFF.

usart_is_rx_ready()

uint32_t usart_is_rx_ready

(

Usart *

p_usart

)

Check if the received data are ready.

Check if Data have been received and loaded into USART_RHR.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Some data has been received.
0	No data has been received.

Definition at line 1688 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_RXRDY) > 0;
}

References Usart::US_CSR, and US_CSR_RXRDY.

Referenced by usart_serial_is_rx_ready().

usart_is_tx_buf_empty()

uint32_t usart_is_tx_buf_empty

(

Usart *

p_usart

)

Check if both transmit buffers are empty.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Transmit buffers are empty.
0	Transmit buffers are not empty.

Definition at line 686 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_TXBUFE) > 0;
}

References Usart::US_CSR, and US_CSR_TXBUFE.

usart_is_tx_buf_end()

uint32_t usart_is_tx_buf_end

(

Usart *

p_usart

)

Check if one transmit buffer is empty.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Transmit is complete.
0	Transmit is still pending.

Definition at line 673 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_ENDTX) > 0;
}

References Usart::US_CSR, and US_CSR_ENDTX.

usart_is_tx_empty()

uint32_t usart_is_tx_empty

(

Usart *

p_usart

)

Check if Transmit Holding Register is empty.

Check if the last data written in USART_THR have been loaded in TSR and the last data loaded in TSR have been transmitted.

Parameters

p_usart

Pointer to a USART instance.

Return values

1	Transmitter is empty.
0	Transmitter is not empty.

Definition at line 1674 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_TXEMPTY) > 0;
}

References Usart::US_CSR, and US_CSR_TXEMPTY.

usart_is_tx_ready()

uint32_t usart_is_tx_ready

(

Usart *

p_usart

)

Check if Transmit is Ready.

Check if data have been loaded in USART_THR and are waiting to be loaded into the Transmit Shift Register (TSR).

Parameters

p_usart

Pointer to a USART instance.

Return values

1	No data is in the Transmit Holding Register.
0	There is data in the Transmit Holding Register.

Definition at line 1659 of file usart.c.

{
    return (p_usart->US_CSR & US_CSR_TXRDY) > 0;
}

References Usart::US_CSR, and US_CSR_TXRDY.

usart_man_disable_drift_compensation()

void usart_man_disable_drift_compensation

(

Usart *

p_usart

)

Disable drift compensation.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 2037 of file usart.c.

{
    p_usart->US_MAN &= ~US_MAN_DRIFT;
}

References Usart::US_MAN, and US_MAN_DRIFT.

usart_man_enable_drift_compensation()

void usart_man_enable_drift_compensation

(

Usart *

p_usart

)

Enable drift compensation.

Note

The 16X clock mode must be enabled.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 2027 of file usart.c.

{
    p_usart->US_MAN |= US_MAN_DRIFT;
}

References Usart::US_MAN, and US_MAN_DRIFT.

usart_man_set_rx_polarity()

void usart_man_set_rx_polarity	(	Usart *	p_usart,
		uint8_t	uc_polarity )

Configure the receiver Manchester polarity when the Manchester encode/decode is enabled.

Parameters

p_usart	Pointer to a USART instance.
uc_polarity	Indicate the receiver Manchester polarity, which should be 0 or 1.

Definition at line 2014 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_RX_MPOL) |
            (uc_polarity << 28);
}

References Usart::US_MAN, and US_MAN_RX_MPOL.

usart_man_set_rx_pre_len()

void usart_man_set_rx_pre_len	(	Usart *	p_usart,
		uint8_t	uc_len )

Configure the detected receiver preamble length when the Manchester encode/decode is enabled.

Parameters

p_usart	Pointer to a USART instance.
uc_len	The detected receiver preamble length, which should be 0 ~ 15.

Definition at line 1984 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_RX_PL_Msk) |
            US_MAN_RX_PL(uc_len);
}

References Usart::US_MAN, US_MAN_RX_PL, and US_MAN_RX_PL_Msk.

usart_man_set_rx_pre_pattern()

void usart_man_set_rx_pre_pattern	(	Usart *	p_usart,
		uint8_t	uc_pattern )

Configure the detected receiver preamble pattern when the Manchester encode/decode is enabled, which should be 0 ~ 3.

Parameters

p_usart	Pointer to a USART instance.
uc_pattern	0 if the preamble is composed of '1's; 1 if the preamble is composed of '0's; 2 if the preamble is composed of '01's; 3 if the preamble is composed of '10's.

Definition at line 2000 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_RX_PP_Msk) |
            (uc_pattern << US_MAN_RX_PP_Pos);
}

References Usart::US_MAN, US_MAN_RX_PP_Msk, and US_MAN_RX_PP_Pos.

usart_man_set_tx_polarity()

void usart_man_set_tx_polarity	(	Usart *	p_usart,
		uint8_t	uc_polarity )

Configure the transmitter Manchester polarity when the Manchester encode/decode is enabled.

Parameters

p_usart	Pointer to a USART instance.
uc_polarity	Indicate the transmitter Manchester polarity, which should be 0 or 1.

Definition at line 1971 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_TX_MPOL) |
            (uc_polarity << 12);
}

References Usart::US_MAN, and US_MAN_TX_MPOL.

usart_man_set_tx_pre_len()

void usart_man_set_tx_pre_len	(	Usart *	p_usart,
		uint8_t	uc_len )

Configure the transmitter preamble length when the Manchester encode/decode is enabled.

Parameters

p_usart	Pointer to a USART instance.
uc_len	The transmitter preamble length, which should be 0 ~ 15.

Definition at line 1941 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_TX_PL_Msk) |
            US_MAN_TX_PL(uc_len);
}

References Usart::US_MAN, US_MAN_TX_PL, and US_MAN_TX_PL_Msk.

usart_man_set_tx_pre_pattern()

void usart_man_set_tx_pre_pattern	(	Usart *	p_usart,
		uint8_t	uc_pattern )

Configure the transmitter preamble pattern when the Manchester encode/decode is enabled, which should be 0 ~ 3.

Parameters

p_usart	Pointer to a USART instance.
uc_pattern	0 if the preamble is composed of '1's; 1 if the preamble is composed of '0's; 2 if the preamble is composed of '01's; 3 if the preamble is composed of '10's.

Definition at line 1957 of file usart.c.

{
    p_usart->US_MAN = (p_usart->US_MAN & ~US_MAN_TX_PP_Msk) |
            (uc_pattern << US_MAN_TX_PP_Pos);
}

References Usart::US_MAN, US_MAN_TX_PP_Msk, and US_MAN_TX_PP_Pos.

usart_putchar()

uint32_t usart_putchar	(	Usart *	p_usart,
		uint32_t	c )

Write to USART Transmit Holding Register.

Note

Before writing user should check if tx is ready (or empty).

Parameters

p_usart	Pointer to a USART instance.
c	Data to be sent.

Return values

0	on success.
1	on failure.

Definition at line 1725 of file usart.c.

{
    while (!(p_usart->US_CSR & US_CSR_TXRDY)) {
    }
 
    p_usart->US_THR = US_THR_TXCHR(c);
 
    return 0;
}

References Usart::US_CSR, US_CSR_TXRDY, Usart::US_THR, and US_THR_TXCHR.

Referenced by usart_write_line().

usart_read()

uint32_t usart_read	(	Usart *	p_usart,
		uint32_t *	c )

Read from USART Receive Holding Register.

Note

Before reading user should check if rx is ready.

Parameters

p_usart	Pointer to a USART instance.
c	Pointer where the one-byte received data will be stored.

Return values

0	on success.
1	if no data is available or errors.

Definition at line 1759 of file usart.c.

{
    if (!(p_usart->US_CSR & US_CSR_RXRDY)) {
        return 1;
    }
 
    /* Read character */
    *c = p_usart->US_RHR & US_RHR_RXCHR_Msk;
 
    return 0;
}

References Usart::US_CSR, US_CSR_RXRDY, Usart::US_RHR, and US_RHR_RXCHR_Msk.

Referenced by usart_serial_getchar().

usart_reset()

void usart_reset

(

Usart *

p_usart

)

Reset the USART and disable TX and RX.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 240 of file usart.c.

{
    /* Disable the Write Protect. */
    usart_disable_writeprotect(p_usart);
 
    /* Reset registers that could cause unpredictable behavior after reset. */
    p_usart->US_MR = 0;
    p_usart->US_RTOR = 0;
    p_usart->US_TTGR = 0;
 
    /* Disable TX and RX. */
    usart_reset_tx(p_usart);
    usart_reset_rx(p_usart);
    /* Reset status bits. */
    usart_reset_status(p_usart);
    /* Turn off RTS and DTR if exist. */
    usart_drive_RTS_pin_high(p_usart);
#if (SAM3S || SAM4S || SAM3U || SAM4L || SAM4E)
    usart_drive_DTR_pin_high(p_usart);
#endif
}

References Usart::US_MR, Usart::US_RTOR, Usart::US_TTGR, usart_disable_writeprotect(), usart_drive_DTR_pin_high(), usart_drive_RTS_pin_high(), usart_reset_rx(), usart_reset_status(), and usart_reset_tx().

Referenced by usart_init_iso7816(), usart_init_rs232(), usart_init_spi_master(), usart_init_spi_slave(), usart_init_sync_master(), and usart_init_sync_slave().

usart_reset_iterations()

void usart_reset_iterations

(

Usart *

p_usart

)

Reset the ITERATION in US_CSR when the ISO7816 mode is enabled.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 623 of file usart.c.

{
    p_usart->US_CR = US_CR_RSTIT;
}

References Usart::US_CR, and US_CR_RSTIT.

usart_reset_nack()

void usart_reset_nack

(

Usart *

p_usart

)

Reset NACK in US_CSR.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 633 of file usart.c.

{
    p_usart->US_CR = US_CR_RSTNACK;
}

References Usart::US_CR, and US_CR_RSTNACK.

usart_reset_rx()

void usart_reset_rx

(

Usart *

p_usart

)

Immediately stop and disable USART receiver.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1446 of file usart.c.

{
    /* Reset Receiver */
    p_usart->US_CR = US_CR_RSTRX | US_CR_RXDIS;
}

References Usart::US_CR, US_CR_RSTRX, and US_CR_RXDIS.

Referenced by usart_reset().

usart_reset_status()

void usart_reset_status

(

Usart *

p_usart

)

Reset status bits (PARE, OVER, MANERR, UNRE and PXBRK in US_CSR).

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1514 of file usart.c.

{
    p_usart->US_CR = US_CR_RSTSTA;
}

References Usart::US_CR, and US_CR_RSTSTA.

Referenced by usart_reset().

usart_reset_tx()

void usart_reset_tx

(

Usart *

p_usart

)

Immediately stop and disable USART transmitter.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1404 of file usart.c.

{
    /* Reset transmitter */
    p_usart->US_CR = US_CR_RSTTX | US_CR_TXDIS;
}

References Usart::US_CR, US_CR_RSTTX, and US_CR_TXDIS.

Referenced by usart_reset().

usart_restart_rx_timeout()

void usart_restart_rx_timeout

(

Usart *

p_usart

)

Restart the receive timeout.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1580 of file usart.c.

{
    p_usart->US_CR = US_CR_RETTO;
}

References Usart::US_CR, and US_CR_RETTO.

usart_send_address()

uint32_t usart_send_address	(	Usart *	p_usart,
		uint32_t	ul_addr )

In Multidrop mode only, the next character written to the US_THR is sent with the address bit set.

Parameters

p_usart	Pointer to a USART instance.
ul_addr	The address to be sent out.

Return values

0	on success.
1	on failure.

Definition at line 1560 of file usart.c.

{
    if ((p_usart->US_MR & US_MR_PAR_MULTIDROP) != US_MR_PAR_MULTIDROP) {
        return 1;
    }
 
    p_usart->US_CR = US_CR_SENDA;
 
    if (usart_write(p_usart, ul_addr)) {
        return 1;
    } else {
        return 0;
    }
}

References Usart::US_CR, US_CR_SENDA, Usart::US_MR, US_MR_PAR_MULTIDROP, and usart_write().

usart_set_async_baudrate()

uint32_t usart_set_async_baudrate	(	Usart *	p_usart,
		uint32_t	baudrate,
		uint32_t	ul_mck )

Calculate a clock divider(CD) and a fractional part (FP) for the USART asynchronous modes to generate a baudrate as close as possible to the baudrate set point.

Note

Baud rate calculation: Baudrate = ul_mck/(Over * (CD + FP/8)) (Over being 16 or 8). The maximal oversampling is selected if it allows to generate a baudrate close to the set point.

Parameters

p_usart	Pointer to a USART instance.
baudrate	Baud rate set point.
ul_mck	USART module input clock frequency.

Return values

0	Baud rate is successfully initialized.
1	Baud rate set point is out of range for the given input clock frequency.

Definition at line 111 of file usart.c.

{
    uint32_t over;
    uint32_t cd_fp;
    uint32_t cd;
    uint32_t fp;
 
    /* Calculate the receiver sampling divide of baudrate clock. */
    if (ul_mck >= HIGH_FRQ_SAMPLE_DIV * baudrate) {
        over = HIGH_FRQ_SAMPLE_DIV;
    } else {
        over = LOW_FRQ_SAMPLE_DIV;
    }
 
    /* Calculate clock divider according to the fraction calculated formula. */
    cd_fp = (8 * ul_mck + (over * baudrate) / 2) / (over * baudrate);
    cd = cd_fp >> 3;
    fp = cd_fp & 0x07;
    if (cd < MIN_CD_VALUE || cd > MAX_CD_VALUE) {
        return 1;
    }
 
    /* Configure the OVER bit in MR register. */
    if (over == 8) {
        p_usart->US_MR |= US_MR_OVER;
    }
 
    /* Configure the baudrate generate register. */
    p_usart->US_BRGR = (cd << US_BRGR_CD_Pos) | (fp << US_BRGR_FP_Pos);
 
    return 0;
}

References HIGH_FRQ_SAMPLE_DIV, LOW_FRQ_SAMPLE_DIV, MAX_CD_VALUE, Usart::US_BRGR, US_BRGR_CD_Pos, US_BRGR_FP_Pos, Usart::US_MR, and US_MR_OVER.

Referenced by usart_init_rs232().

usart_set_iso7816_clock()

uint32_t usart_set_iso7816_clock ( Usart * p_usart, uint32_t clock, uint32_t ul_mck )

static

Calculate a clock divider (CD) for the USART ISO7816 mode to generate an ISO7816 clock as close as possible to the clock set point.

Note

ISO7816 clock calculation: Clock = ul_mck / cd

Parameters

p_usart	Pointer to a USART instance.
clock	ISO7816 clock set point.
ul_mck	USART module input clock frequency.

Return values

0	ISO7816 clock is successfully initialized.
1	ISO7816 clock set point is out of range for the given input clock frequency.

Definition at line 524 of file usart.c.

{
    uint32_t cd;
 
    /* Calculate clock divider according to the formula in ISO7816 mode. */
    cd = (ul_mck + clock / 2) / clock;
 
    if (cd < MIN_CD_VALUE || cd > MAX_CD_VALUE) {
        return 1;
    }
 
    p_usart->US_MR = (p_usart->US_MR & ~(US_MR_USCLKS_Msk | US_MR_SYNC |
            US_MR_OVER)) | US_MR_USCLKS_MCK | US_MR_CLKO;
 
    /* Configure the baudrate generate register. */
    p_usart->US_BRGR = cd << US_BRGR_CD_Pos;
 
    return 0;
}

References MAX_CD_VALUE, Usart::US_BRGR, US_BRGR_CD_Pos, Usart::US_MR, US_MR_CLKO, US_MR_OVER, US_MR_SYNC, US_MR_USCLKS_MCK, and US_MR_USCLKS_Msk.

Referenced by usart_init_iso7816().

usart_set_rx_timeout()

void usart_set_rx_timeout	(	Usart *	p_usart,
		uint32_t	timeout )

Configure the receive timeout register.

Parameters

p_usart	Pointer to a USART instance.
timeout	The value of receive timeout.

Definition at line 1458 of file usart.c.

{
    p_usart->US_RTOR = timeout;
}

References Usart::US_RTOR.

usart_set_spi_master_baudrate()

uint32_t usart_set_spi_master_baudrate ( Usart * p_usart, uint32_t baudrate, uint32_t ul_mck )

static

Calculate a clock divider (CD) for the USART SPI master mode to generate a baud rate as close as possible to the baud rate set point.

Note

Baud rate calculation: \( Baudrate = \frac{SelectedClock}{CD} \).

Parameters

p_usart	Pointer to a USART instance.
baudrate	Baud rate set point.
ul_mck	USART module input clock frequency.

Return values

0	Baud rate is successfully initialized.
1	Baud rate set point is out of range for the given input clock frequency.

Definition at line 206 of file usart.c.

{
    uint32_t cd;
 
    /* Calculate the clock divider according to the formula in SPI mode. */
    cd = (ul_mck + baudrate / 2) / baudrate;
 
    if (cd < MIN_CD_VALUE_SPI || cd > MAX_CD_VALUE) {
        return 1;
    }
 
    p_usart->US_BRGR = cd << US_BRGR_CD_Pos;
 
    return 0;
}

References MAX_CD_VALUE, Usart::US_BRGR, and US_BRGR_CD_Pos.

Referenced by usart_init_spi_master().

usart_set_spi_slave_baudrate()

void usart_set_spi_slave_baudrate ( Usart * p_usart )

static

Select the SCK pin as the source of baudrate for the USART SPI slave mode.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 229 of file usart.c.

{
    p_usart->US_MR &= ~US_MR_USCLKS_Msk;
    p_usart->US_MR |= US_MR_USCLKS_SCK;
}

References Usart::US_MR, US_MR_USCLKS_Msk, and US_MR_USCLKS_SCK.

Referenced by usart_init_spi_slave().

usart_set_sync_master_baudrate()

uint32_t usart_set_sync_master_baudrate ( Usart * p_usart, uint32_t baudrate, uint32_t ul_mck )

static

Calculate a clock divider for the USART synchronous master modes to generate a baudrate as close as possible to the baudrate set point.

Note

Synchronous baudrate calculation: baudrate = ul_mck / cd

Parameters

p_usart	Pointer to a USART instance.
baudrate	Baud rate set point.
ul_mck	USART module input clock frequency.

Return values

0	Baud rate is successfully initialized.
1	Baud rate set point is out of range for the given input clock frequency.

Definition at line 159 of file usart.c.

{
    uint32_t cd;
 
    /* Calculate clock divider according to the formula in synchronous mode. */
    cd = (ul_mck + baudrate / 2) / baudrate;
 
    if (cd < MIN_CD_VALUE || cd > MAX_CD_VALUE) {
        return 1;
    }
 
    /* Configure the baudrate generate register. */
    p_usart->US_BRGR = cd << US_BRGR_CD_Pos;
 
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USCLKS_Msk) |
            US_MR_USCLKS_MCK | US_MR_SYNC;
    return 0;
}

References MAX_CD_VALUE, Usart::US_BRGR, US_BRGR_CD_Pos, Usart::US_MR, US_MR_SYNC, US_MR_USCLKS_MCK, and US_MR_USCLKS_Msk.

Referenced by usart_init_sync_master().

usart_set_sync_slave_baudrate()

void usart_set_sync_slave_baudrate ( Usart * p_usart )

static

Select the SCK pin as the source of baud rate for the USART synchronous slave modes.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 185 of file usart.c.

{
    p_usart->US_MR = (p_usart->US_MR & ~US_MR_USCLKS_Msk) |
            US_MR_USCLKS_SCK | US_MR_SYNC;
}

References Usart::US_MR, US_MR_SYNC, US_MR_USCLKS_Msk, and US_MR_USCLKS_SCK.

Referenced by usart_init_sync_slave().

usart_set_tx_timeguard()

void usart_set_tx_timeguard	(	Usart *	p_usart,
		uint32_t	timeguard )

Configure the transmit timeguard register.

Parameters

p_usart	Pointer to a USART instance.
timeguard	The value of transmit timeguard.

Definition at line 1416 of file usart.c.

{
    p_usart->US_TTGR = timeguard;
}

References Usart::US_TTGR.

usart_spi_force_chip_select()

void usart_spi_force_chip_select

(

Usart *

p_usart

)

Drive the slave select line NSS (RTS pin) to 0 in SPI master mode.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1634 of file usart.c.

{
    p_usart->US_CR = US_CR_FCS;
}

References Usart::US_CR, and US_CR_FCS.

usart_spi_release_chip_select()

void usart_spi_release_chip_select

(

Usart *

p_usart

)

Drive the slave select line NSS (RTS pin) to 1 in SPI master mode.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1644 of file usart.c.

{
    p_usart->US_CR = US_CR_RCS;
}

References Usart::US_CR, and US_CR_RCS.

usart_start_rx_timeout()

void usart_start_rx_timeout

(

Usart *

p_usart

)

Start waiting for a character before clocking the timeout count.

Reset the status bit TIMEOUT in US_CSR.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1545 of file usart.c.

{
    p_usart->US_CR = US_CR_STTTO;
}

References Usart::US_CR, and US_CR_STTTO.

usart_start_tx_break()

void usart_start_tx_break

(

Usart *

p_usart

)

Start transmission of a break.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1524 of file usart.c.

{
    p_usart->US_CR = US_CR_STTBRK;
}

References Usart::US_CR, and US_CR_STTBRK.

usart_stop_tx_break()

void usart_stop_tx_break

(

Usart *

p_usart

)

Stop transmission of a break.

Parameters

p_usart

Pointer to a USART instance.

Definition at line 1534 of file usart.c.

{
    p_usart->US_CR = US_CR_STPBRK;
}

References Usart::US_CR, and US_CR_STPBRK.

usart_write()

uint32_t usart_write	(	Usart *	p_usart,
		uint32_t	c )

Write to USART Transmit Holding Register.

Note

Before writing user should check if tx is ready (or empty).

Parameters

p_usart	Pointer to a USART instance.
c	Data to be sent.

Return values

0	on success.
1	on failure.

Definition at line 1704 of file usart.c.

{
    if (!(p_usart->US_CSR & US_CSR_TXRDY)) {
        return 1;
    }
 
    p_usart->US_THR = US_THR_TXCHR(c);
    return 0;
}

References Usart::US_CSR, US_CSR_TXRDY, Usart::US_THR, and US_THR_TXCHR.

Referenced by usart_send_address(), and usart_serial_putchar().

usart_write_line()

void usart_write_line	(	Usart *	p_usart,
		const char *	string )

Write one-line string through USART.

Parameters

p_usart	Pointer to a USART instance.
string	Pointer to one-line string to be sent.

Definition at line 1741 of file usart.c.

{
    while (*string != '\0') {
        usart_putchar(p_usart, *string++);
    }
}

References usart_putchar().