circuitpython/atmel-samd/asf/sam0/drivers/sercom/usart/usart.h

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C

/**
*
* \file
*
* \brief SAM SERCOM USART Driver
*
* Copyright (C) 2012-2016 Atmel Corporation. All rights reserved.
*
* \asf_license_start
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
* Atmel microcontroller product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
/*
* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
*/
#ifndef USART_H_INCLUDED
#define USART_H_INCLUDED
/**
* \defgroup asfdoc_sam0_sercom_usart_group SAM Serial USART (SERCOM USART) Driver
*
* This driver for Atmel&reg; | SMART ARM&reg;-based microcontrollers provides
* an interface for the configuration and management of the SERCOM module in
* its USART mode to transfer or receive USART data frames. The following driver
* API modes are covered by this manual:
*
* - Polled APIs
* \if USART_CALLBACK_MODE
* - Callback APIs
* \endif
*
* The following peripheral is used by this module:
* - SERCOM (Serial Communication Interface)
*
* The following devices can use this module:
* - Atmel | SMART SAM D20/D21
* - Atmel | SMART SAM R21
* - Atmel | SMART SAM D09/D10/D11
* - Atmel | SMART SAM D10/D11
* - Atmel | SMART SAM L21/L22
* - Atmel | SMART SAM DA1
* - Atmel | SMART SAM C20/C21
*
* The outline of this documentation is as follows:
* - \ref asfdoc_sam0_sercom_usart_prerequisites
* - \ref asfdoc_sam0_sercom_usart_overview
* - \ref asfdoc_sam0_sercom_usart_special_considerations
* - \ref asfdoc_sam0_sercom_usart_extra_info
* - \ref asfdoc_sam0_sercom_usart_examples
* - \ref asfdoc_sam0_sercom_usart_api_overview
*
* \section asfdoc_sam0_sercom_usart_prerequisites Prerequisites
*
* To use the USART you need to have a GCLK generator enabled and running
* that can be used as the SERCOM clock source. This can either be configured
* in conf_clocks.h or by using the system clock driver.
*
* \section asfdoc_sam0_sercom_usart_overview Module Overview
*
* This driver will use one (or more) SERCOM interface(s) in the system
* and configure it to run as a USART interface in either synchronous
* or asynchronous mode.
*
* \subsection asfdoc_sam0_sercom_usart_features Driver Feature Macro Definition
* <table>
* <tr>
* <th>Driver Feature Macro</th>
* <th>Supported devices</th>
* </tr>
* <tr>
* <td>FEATURE_USART_SYNC_SCHEME_V2</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_OVER_SAMPLE</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_HARDWARE_FLOW_CONTROL</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_IRDA</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_LIN_SLAVE</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_COLLISION_DECTION</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_START_FRAME_DECTION</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_IMMEDIATE_BUFFER_OVERFLOW_NOTIFICATION</td>
* <td>SAM D21/R21/D09/D10/D11/L21/L22/DA1/C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_RS485</td>
* <td>SAM C20/C21</td>
* </tr>
* <tr>
* <td>FEATURE_USART_LIN_MASTER</td>
* <td>SAM L22/C20/C21</td>
* </tr>
* </table>
* \note The specific features are only available in the driver when the
* selected device supports those features.
*
* \subsection asfdoc_sam0_sercom_usart_overview_frame_format Frame Format
*
* Communication is based on frames, where the frame format can be customized
* to accommodate a wide range of standards. A frame consists of a start bit,
* a number of data bits, an optional parity bit for error detection as well
* as a configurable length stop bit(s) - see
* \ref asfdoc_sam0_sercom_usart_frame_diagram "the figure below".
* \ref asfdoc_sam0_sercom_usart_frame_params "The table below" shows the
* available parameters you can change in a frame.
*
* \anchor asfdoc_sam0_sercom_usart_frame_params
* <table>
* <caption>USART Frame Parameters</caption>
* <tr>
* <th>Parameter</th>
* <th>Options</th>
* </tr>
* <tr>
* <td>Start bit</td>
* <td>1</td>
* </tr>
* <tr>
* <td>Data bits</td>
* <td>5, 6, 7, 8, 9</td>
* </tr>
* <tr>
* <td>Parity bit</td>
* <td>None, Even, Odd</td>
* </tr>
* <tr>
* <td>Stop bits</td>
* <td>1, 2</td>
* </tr>
* </table>
*
* \anchor asfdoc_sam0_sercom_usart_frame_diagram
* \image html usart_frame.svg "USART Frame Overview" width=100%
*
* \subsection asfdoc_sam0_sercom_usart_overview_sync Synchronous Mode
*
* In synchronous mode a dedicated clock line is provided; either by the USART
* itself if in master mode, or by an external master if in slave mode.
* Maximum transmission speed is the same as the GCLK clocking the USART
* peripheral when in slave mode, and the GCLK divided by two if in
* master mode. In synchronous mode the interface needs three lines to
* communicate:
* - TX (Transmit pin)
* - RX (Receive pin)
* - XCK (Clock pin)
*
* \subsubsection asfdoc_sam0_sercom_usart_overview_sync_sampling Data Sampling
* In synchronous mode the data is sampled on either the rising or falling edge
* of the clock signal. This is configured by setting the clock polarity in the
* configuration struct.
*
* \subsection asfdoc_sam0_sercom_usart_overview_async Asynchronous Mode
*
* In asynchronous mode no dedicated clock line is used, and the communication
* is based on matching the clock speed on the transmitter and receiver. The
* clock is generated from the internal SERCOM baudrate generator, and the
* frames are synchronized by using the frame start bits. Maximum transmission
* speed is limited to the SERCOM GCLK divided by 16.
* In asynchronous mode the interface only needs two lines to communicate:
* - TX (Transmit pin)
* - RX (Receive pin)
*
* \subsubsection asfdoc_sam0_sercom_usart_overview_async_clock_matching Transmitter/receiver Clock Matching
*
* For successful transmit and receive using the asynchronous mode the receiver
* and transmitter clocks needs to be closely matched. When receiving a frame
* that does not match the selected baudrate closely enough the receiver will
* be unable to synchronize the frame(s), and garbage transmissions will
* result.
*
* \subsection asfdoc_sam0_sercom_usart_parity Parity
* Parity can be enabled to detect if a transmission was in error. This is done
* by counting the number of "1" bits in the frame. When using even parity the
* parity bit will be set if the total number of "1"s in the frame are an even
* number. If using odd parity the parity bit will be set if the total number
* of "1"s are odd.
*
* When receiving a character the receiver will count the number of "1"s in the
* frame and give an error if the received frame and parity bit disagree.
*
* \subsection asfdoc_sam0_sercom_usart_overview_pin_configuration GPIO Configuration
*
* The SERCOM module has four internal pads; the RX pin can be placed freely on
* any one of the four pads, and the TX and XCK pins have two predefined
* positions that can be selected as a pair. The pads can then be routed to an
* external GPIO pin using the normal pin multiplexing scheme on the SAM.
*
* \section asfdoc_sam0_sercom_usart_special_considerations Special Considerations
*
* \if USART_CALLBACK_MODE
* Never execute large portions of code in the callbacks. These
* are run from the interrupt routine, and thus having long callbacks will
* keep the processor in the interrupt handler for an equally long time.
* A common way to handle this is to use global flags signaling the
* main application that an interrupt event has happened, and only do the
* minimal needed processing in the callback.
* \else
* No special considerations.
* \endif
*
* \section asfdoc_sam0_sercom_usart_extra_info Extra Information
*
* For extra information, see \ref asfdoc_sam0_sercom_usart_extra. This includes:
* - \ref asfdoc_sam0_sercom_usart_extra_acronyms
* - \ref asfdoc_sam0_sercom_usart_extra_dependencies
* - \ref asfdoc_sam0_sercom_usart_extra_errata
* - \ref asfdoc_sam0_sercom_usart_extra_history
*
* \section asfdoc_sam0_sercom_usart_examples Examples
*
* For a list of examples related to this driver, see
* \ref asfdoc_sam0_sercom_usart_exqsg.
*
* \section asfdoc_sam0_sercom_usart_api_overview API Overview
* @{
*/
#include <compiler.h>
#include <sercom.h>
#include <pinmux.h>
#if USART_CALLBACK_MODE == true
# include <sercom_interrupt.h>
#endif
#ifdef __cplusplus
extern "C" {
#endif
/**
* \name Driver Feature Definition
* Define SERCOM USART features set according to different device family.
* @{
*/
#if (SAMD21) || (SAMR21) || (SAMD09) || (SAMD10) || (SAMD11) || (SAML21) || \
(SAML22) ||(SAMDA1) || (SAMC20) || (SAMC21) || (SAMR30) || defined(__DOXYGEN__)
/** USART sync scheme version 2. */
# define FEATURE_USART_SYNC_SCHEME_V2
/** USART oversampling. */
# define FEATURE_USART_OVER_SAMPLE
/** USART hardware control flow. */
# define FEATURE_USART_HARDWARE_FLOW_CONTROL
/** IrDA mode. */
# define FEATURE_USART_IRDA
/** LIN slave mode. */
# define FEATURE_USART_LIN_SLAVE
/** USART collision detection. */
# define FEATURE_USART_COLLISION_DECTION
/** USART start frame detection. */
# define FEATURE_USART_START_FRAME_DECTION
/** USART start buffer overflow notification. */
# define FEATURE_USART_IMMEDIATE_BUFFER_OVERFLOW_NOTIFICATION
#endif
#if (SAML22) || defined(__DOXYGEN__)
/** ISO7816 for smart card interfacing. */
#define FEATURE_USART_ISO7816
#endif
#if (SAMC20) || (SAMC21) || defined(__DOXYGEN__)
/** LIN master mode. */
#define FEATURE_USART_LIN_MASTER
#endif
#if (SAML22) || (SAMC20) || (SAMC21) || defined(__DOXYGEN__)
/** RS485 mode. */
# define FEATURE_USART_RS485
#endif
/*@}*/
#ifdef FEATURE_USART_LIN_MASTER
/**
* \brief LIN node type
*
* LIN node type.
*/
enum lin_node_type {
/** LIN master mode */
LIN_MASTER_NODE = SERCOM_USART_CTRLA_FORM(0x02),
/** LIN slave mode */
LIN_SLAVE_NODE = SERCOM_USART_CTRLA_FORM(0x04),
/** Neither LIN master nor LIN slave mode */
LIN_INVALID_MODE = SERCOM_USART_CTRLA_FORM(0x00),
};
/**
* \brief LIN master command enum
*
* LIN master command enum.
*/
enum lin_master_cmd {
/** LIN master software control transmission command */
LIN_MASTER_SOFTWARE_CONTROL_TRANSMIT_CMD = SERCOM_USART_CTRLB_LINCMD(0x01),
/** LIN master automatically transmission command */
LIN_MASTER_AUTO_TRANSMIT_CMD = SERCOM_USART_CTRLB_LINCMD(0x02),
};
/**
* \brief LIN master header delay
*
* LIN master header delay between break and sync transmission,
* and between the sync and identifier (ID) fields.
* This field is only valid when using automatically transmission command
*/
enum lin_master_header_delay {
/** Delay between break and sync transmission is 1 bit time.
Delay between sync and ID transmission is 1 bit time. */
LIN_MASTER_HEADER_DELAY_0 = SERCOM_USART_CTRLC_HDRDLY(0x0),
/** Delay between break and sync transmission is 4 bit time.
Delay between sync and ID transmission is 4 bit time. */
LIN_MASTER_HEADER_DELAY_1 = SERCOM_USART_CTRLC_HDRDLY(0x01),
/** Delay between break and sync transmission is 8 bit time.
Delay between sync and ID transmission is 4 bit time. */
LIN_MASTER_HEADER_DELAY_2 = SERCOM_USART_CTRLC_HDRDLY(0x02),
/** Delay between break and sync transmission is 14 bit time.
Delay between sync and ID transmission is 4 bit time. */
LIN_MASTER_HEADER_DELAY_3 = SERCOM_USART_CTRLC_HDRDLY(0x03),
};
/**
* \brief LIN master break length
*
* Length of the break field transmitted when in LIN master mode
*/
enum lin_master_break_length {
/** Break field transmission is 13 bit times */
LIN_MASTER_BREAK_LENGTH_13_BIT = SERCOM_USART_CTRLC_BRKLEN(0x0),
/** Break field transmission is 17 bit times */
LIN_MASTER_BREAK_LENGTH_17_BIT = SERCOM_USART_CTRLC_BRKLEN(0x1),
/** Break field transmission is 21 bit times */
LIN_MASTER_BREAK_LENGTH_21_BIT = SERCOM_USART_CTRLC_BRKLEN(0x2),
/** Break field transmission is 26 bit times */
LIN_MASTER_BREAK_LENGTH_26_BIT = SERCOM_USART_CTRLC_BRKLEN(0x3),
};
#endif
#ifdef FEATURE_USART_ISO7816
/**
* \brief ISO7816 protocol type
*
* ISO7816 protocol type.
*/
enum iso7816_protocol_type {
/** ISO7816 protocol type 0 */
ISO7816_PROTOCOL_T_0 = SERCOM_USART_CTRLA_CMODE,
/** ISO7816 protocol type 1 */
ISO7816_PROTOCOL_T_1 = (0x0ul << SERCOM_USART_CTRLA_CMODE_Pos),
};
/**
* \brief ISO7816 guard time
*
* The value of ISO7816 guard time.
*/
enum iso7816_guard_time {
/** The guard time is 2-bit times */
ISO7816_GUARD_TIME_2_BIT = 2,
/** The guard time is 3-bit times */
ISO7816_GUARD_TIME_3_BIT,
/** The guard time is 4-bit times */
ISO7816_GUARD_TIME_4_BIT,
/** The guard time is 5-bit times */
ISO7816_GUARD_TIME_5_BIT,
/** The guard time is 6-bit times */
ISO7816_GUARD_TIME_6_BIT,
/** The guard time is 7-bit times */
ISO7816_GUARD_TIME_7_BIT,
};
/**
* \brief ISO7816 receive NACK inhibit
*
* The value of ISO7816 receive NACK inhibit.
*/
enum iso7816_inhibit_nack {
/** The NACK is generated */
ISO7816_INHIBIT_NACK_DISABLE = (0x0ul << SERCOM_USART_CTRLC_INACK_Pos),
/** The NACK is not generated */
ISO7816_INHIBIT_NACK_ENABLE = SERCOM_USART_CTRLC_INACK,
};
/**
* \brief ISO7816 disable successive receive NACK
*
* The value of ISO7816 disable successive receive NACK.
*/
enum iso7816_successive_recv_nack {
/** The successive receive NACK is enable. */
ISO7816_SUCCESSIVE_RECV_NACK_DISABLE = (0x0ul << SERCOM_USART_CTRLC_INACK_Pos),
/** The successive receive NACK is disable. */
ISO7816_SUCCESSIVE_RECV_NACK_ENABLE = SERCOM_USART_CTRLC_DSNACK,
};
/**
* \brief ISO7816 configuration struct
*
* ISO7816 configuration structure.
*/
struct iso7816_config_t {
/* ISO7816 mode enable */
bool enabled;
/** ISO7816 protocol type */
enum iso7816_protocol_type protocol_t;
/** Enable inverse transmission and reception */
bool enable_inverse;
/** Guard time, which lasts two bit times */
enum iso7816_guard_time guard_time;
/**
* Inhibit Non Acknowledge:
* - 0: the NACK is generated;
* - 1: the NACK is not generated.
*/
enum iso7816_inhibit_nack inhibit_nack;
/**
* Disable successive NACKs.
* - 0: NACK is sent on the ISO line as soon as a parity error occurs
* in the received character. Successive parity errors are counted up to
* the value in the max_iterations field. These parity errors generate
* a NACK on the ISO line. As soon as this value is reached, no additional
* NACK is sent on the ISO line. The ITERATION flag is asserted.
*/
enum iso7816_successive_recv_nack successive_recv_nack;
/* Max number of repetitions */
uint32_t max_iterations;
};
#endif
#ifndef PINMUX_DEFAULT
/** Default pinmux */
# define PINMUX_DEFAULT 0
#endif
#ifndef PINMUX_UNUSED
/** Unused pinmux */
# define PINMUX_UNUSED 0xFFFFFFFF
#endif
#ifndef USART_TIMEOUT
/** USART timeout value */
# define USART_TIMEOUT 0xFFFF
#endif
#if USART_CALLBACK_MODE == true
/**
* \brief USART callback enum
*
* Callbacks for the Asynchronous USART driver.
*/
enum usart_callback {
/** Callback for buffer transmitted */
USART_CALLBACK_BUFFER_TRANSMITTED,
/** Callback for buffer received */
USART_CALLBACK_BUFFER_RECEIVED,
/** Callback for error */
USART_CALLBACK_ERROR,
#ifdef FEATURE_USART_LIN_SLAVE
/** Callback for break character is received */
USART_CALLBACK_BREAK_RECEIVED,
#endif
#ifdef FEATURE_USART_HARDWARE_FLOW_CONTROL
/** Callback for a change is detected on the CTS pin */
USART_CALLBACK_CTS_INPUT_CHANGE,
#endif
#ifdef FEATURE_USART_START_FRAME_DECTION
/** Callback for a start condition is detected on the RxD line */
USART_CALLBACK_START_RECEIVED,
#endif
# if !defined(__DOXYGEN__)
/** Number of available callbacks */
USART_CALLBACK_N,
# endif
};
#endif
/**
* \brief USART Data Order enum
*
* The data order decides which MSB or LSB is shifted out first when data is
* transferred.
*/
enum usart_dataorder {
/** The MSB will be shifted out first during transmission,
* and shifted in first during reception */
USART_DATAORDER_MSB = 0,
/** The LSB will be shifted out first during transmission,
* and shifted in first during reception */
USART_DATAORDER_LSB = SERCOM_USART_CTRLA_DORD,
};
/**
* \brief USART Transfer mode enum
*
* Select USART transfer mode.
*/
enum usart_transfer_mode {
/** Transfer of data is done synchronously */
USART_TRANSFER_SYNCHRONOUSLY = (SERCOM_USART_CTRLA_CMODE),
/** Transfer of data is done asynchronously */
USART_TRANSFER_ASYNCHRONOUSLY = (0x0ul << SERCOM_USART_CTRLA_CMODE_Pos),
};
/**
* \brief USART Parity enum
*
* Select parity USART parity mode.
*/
enum usart_parity {
/** For odd parity checking, the parity bit will be set if number of
* ones being transferred is even */
USART_PARITY_ODD = SERCOM_USART_CTRLB_PMODE,
/** For even parity checking, the parity bit will be set if number of
* ones being received is odd */
USART_PARITY_EVEN = 0,
/** No parity checking will be executed, and there will be no parity bit
* in the received frame */
USART_PARITY_NONE = 0xFF,
};
/**
* \brief USART signal MUX settings
*
* Set the functionality of the SERCOM pins.
*
* See \ref asfdoc_sam0_sercom_usart_mux_settings for a description of the
* various MUX setting options.
*/
enum usart_signal_mux_settings {
#ifdef FEATURE_USART_HARDWARE_FLOW_CONTROL
/** MUX setting RX_0_TX_0_XCK_1 */
USART_RX_0_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(0) | SERCOM_USART_CTRLA_TXPO(0)),
/** MUX setting RX_0_TX_2_XCK_3 */
USART_RX_0_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(0) | SERCOM_USART_CTRLA_TXPO(1)),
/** MUX setting USART_RX_0_TX_0_RTS_2_CTS_3 */
USART_RX_0_TX_0_RTS_2_CTS_3 = (SERCOM_USART_CTRLA_RXPO(0) | SERCOM_USART_CTRLA_TXPO(2)),
/** MUX setting RX_1_TX_0_XCK_1 */
USART_RX_1_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(1) | SERCOM_USART_CTRLA_TXPO(0)),
/** MUX setting RX_1_TX_2_XCK_3 */
USART_RX_1_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(1) | SERCOM_USART_CTRLA_TXPO(1)),
/** MUX setting USART_RX_1_TX_0_RTS_2_CTS_3 */
USART_RX_1_TX_0_RTS_2_CTS_3 = (SERCOM_USART_CTRLA_RXPO(1) | SERCOM_USART_CTRLA_TXPO(2)),
/** MUX setting RX_2_TX_0_XCK_1 */
USART_RX_2_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(2) | SERCOM_USART_CTRLA_TXPO(0)),
/** MUX setting RX_2_TX_2_XCK_3 */
USART_RX_2_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(2) | SERCOM_USART_CTRLA_TXPO(1)),
/** MUX setting USART_RX_2_TX_0_RTS_2_CTS_3 */
USART_RX_2_TX_0_RTS_2_CTS_3 = (SERCOM_USART_CTRLA_RXPO(2) | SERCOM_USART_CTRLA_TXPO(2)),
/** MUX setting RX_3_TX_0_XCK_1 */
USART_RX_3_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(3) | SERCOM_USART_CTRLA_TXPO(0)),
/** MUX setting RX_3_TX_2_XCK_3 */
USART_RX_3_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(3) | SERCOM_USART_CTRLA_TXPO(1)),
/** MUX setting USART_RX_3_TX_0_RTS_2_CTS_3 */
USART_RX_3_TX_0_RTS_2_CTS_3 = (SERCOM_USART_CTRLA_RXPO(3) | SERCOM_USART_CTRLA_TXPO(2)),
#ifdef FEATURE_USART_RS485
/** MUX setting USART_RX_0_TX_0_XCK_1_TE_2 */
USART_RX_0_TX_0_XCK_1_TE_2 = (SERCOM_USART_CTRLA_RXPO(0) | SERCOM_USART_CTRLA_TXPO(3)),
/** MUX setting USART_RX_1_TX_0_XCK_1_TE_2 */
USART_RX_1_TX_0_XCK_1_TE_2 = (SERCOM_USART_CTRLA_RXPO(1) | SERCOM_USART_CTRLA_TXPO(3)),
/** MUX setting USART_RX_2_TX_0_XCK_1_TE_2 */
USART_RX_2_TX_0_XCK_1_TE_2 = (SERCOM_USART_CTRLA_RXPO(2) | SERCOM_USART_CTRLA_TXPO(3)),
/** MUX setting USART_RX_3_TX_0_XCK_1_TE_2 */
USART_RX_3_TX_0_XCK_1_TE_2 = (SERCOM_USART_CTRLA_RXPO(3) | SERCOM_USART_CTRLA_TXPO(3)),
#endif
#else
/** MUX setting RX_0_TX_0_XCK_1 */
USART_RX_0_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(0)),
/** MUX setting RX_0_TX_2_XCK_3 */
USART_RX_0_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(0) | SERCOM_USART_CTRLA_TXPO),
/** MUX setting RX_1_TX_0_XCK_1 */
USART_RX_1_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(1)),
/** MUX setting RX_1_TX_2_XCK_3 */
USART_RX_1_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(1) | SERCOM_USART_CTRLA_TXPO),
/** MUX setting RX_2_TX_0_XCK_1 */
USART_RX_2_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(2)),
/** MUX setting RX_2_TX_2_XCK_3 */
USART_RX_2_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(2) | SERCOM_USART_CTRLA_TXPO),
/** MUX setting RX_3_TX_0_XCK_1 */
USART_RX_3_TX_0_XCK_1 = (SERCOM_USART_CTRLA_RXPO(3)),
/** MUX setting RX_3_TX_2_XCK_3 */
USART_RX_3_TX_2_XCK_3 = (SERCOM_USART_CTRLA_RXPO(3) | SERCOM_USART_CTRLA_TXPO),
#endif
};
/**
* \brief USART Stop Bits enum
*
* Number of stop bits for a frame.
*/
enum usart_stopbits {
/** Each transferred frame contains one stop bit */
USART_STOPBITS_1 = 0,
/** Each transferred frame contains two stop bits */
USART_STOPBITS_2 = SERCOM_USART_CTRLB_SBMODE,
};
/**
* \brief USART Character Size
*
* Number of bits for the character sent in a frame.
*/
enum usart_character_size {
/** The char being sent in a frame is five bits long */
USART_CHARACTER_SIZE_5BIT = SERCOM_USART_CTRLB_CHSIZE(5),
/** The char being sent in a frame is six bits long */
USART_CHARACTER_SIZE_6BIT = SERCOM_USART_CTRLB_CHSIZE(6),
/** The char being sent in a frame is seven bits long */
USART_CHARACTER_SIZE_7BIT = SERCOM_USART_CTRLB_CHSIZE(7),
/** The char being sent in a frame is eight bits long */
USART_CHARACTER_SIZE_8BIT = SERCOM_USART_CTRLB_CHSIZE(0),
/** The char being sent in a frame is nine bits long */
USART_CHARACTER_SIZE_9BIT = SERCOM_USART_CTRLB_CHSIZE(1),
};
#ifdef FEATURE_USART_OVER_SAMPLE
/**
* \brief USART Sample Rate
*
* The value of sample rate and baudrate generation mode.
*/
enum usart_sample_rate {
/** 16x over-sampling using arithmetic baudrate generation */
USART_SAMPLE_RATE_16X_ARITHMETIC = SERCOM_USART_CTRLA_SAMPR(0),
/** 16x over-sampling using fractional baudrate generation */
USART_SAMPLE_RATE_16X_FRACTIONAL = SERCOM_USART_CTRLA_SAMPR(1),
/** 8x over-sampling using arithmetic baudrate generation */
USART_SAMPLE_RATE_8X_ARITHMETIC = SERCOM_USART_CTRLA_SAMPR(2),
/** 8x over-sampling using fractional baudrate generation */
USART_SAMPLE_RATE_8X_FRACTIONAL = SERCOM_USART_CTRLA_SAMPR(3),
/** 3x over-sampling using arithmetic baudrate generation */
USART_SAMPLE_RATE_3X_ARITHMETIC = SERCOM_USART_CTRLA_SAMPR(4),
};
/**
* \brief USART Sample Adjustment
*
* The value of sample number used for majority voting.
*/
enum usart_sample_adjustment {
/** The first, middle and last sample number used for majority voting is 7-8-9 */
USART_SAMPLE_ADJUSTMENT_7_8_9 = SERCOM_USART_CTRLA_SAMPA(0),
/** The first, middle and last sample number used for majority voting is 9-10-11 */
USART_SAMPLE_ADJUSTMENT_9_10_11 = SERCOM_USART_CTRLA_SAMPA(1),
/** The first, middle and last sample number used for majority voting is 11-12-13 */
USART_SAMPLE_ADJUSTMENT_11_12_13 = SERCOM_USART_CTRLA_SAMPA(2),
/** The first, middle and last sample number used for majority voting is 13-14-15 */
USART_SAMPLE_ADJUSTMENT_13_14_15 = SERCOM_USART_CTRLA_SAMPA(3),
};
#endif
#ifdef FEATURE_USART_RS485
/**
* \brief RS485 Guard Time
*
* The value of RS485 guard time.
*/
enum rs485_guard_time {
/** The guard time is 0-bit time */
RS485_GUARD_TIME_0_BIT = 0,
/** The guard time is 1-bit time */
RS485_GUARD_TIME_1_BIT,
/** The guard time is 2-bit times */
RS485_GUARD_TIME_2_BIT,
/** The guard time is 3-bit times */
RS485_GUARD_TIME_3_BIT,
/** The guard time is 4-bit times */
RS485_GUARD_TIME_4_BIT,
/** The guard time is 5-bit times */
RS485_GUARD_TIME_5_BIT,
/** The guard time is 6-bit times */
RS485_GUARD_TIME_6_BIT,
/** The guard time is 7-bit times */
RS485_GUARD_TIME_7_BIT,
};
#endif
/**
* \brief USART Transceiver
*
* Select Receiver or Transmitter.
*/
enum usart_transceiver_type {
/** The parameter is for the Receiver */
USART_TRANSCEIVER_RX,
/** The parameter is for the Transmitter */
USART_TRANSCEIVER_TX,
};
/**
* \brief USART configuration struct
*
* Configuration options for USART.
*/
struct usart_config {
/** USART bit order (MSB or LSB first) */
enum usart_dataorder data_order;
/** USART in asynchronous or synchronous mode */
enum usart_transfer_mode transfer_mode;
/** USART parity */
enum usart_parity parity;
/** Number of stop bits */
enum usart_stopbits stopbits;
/** USART character size */
enum usart_character_size character_size;
/** USART pin out */
enum usart_signal_mux_settings mux_setting;
#ifdef FEATURE_USART_OVER_SAMPLE
/** USART sample rate */
enum usart_sample_rate sample_rate;
/** USART sample adjustment */
enum usart_sample_adjustment sample_adjustment;
#endif
#ifdef FEATURE_USART_IMMEDIATE_BUFFER_OVERFLOW_NOTIFICATION
/** Controls when the buffer overflow status bit is asserted when a buffer overflow occurs */
bool immediate_buffer_overflow_notification;
#endif
#ifdef FEATURE_USART_IRDA
/** Enable IrDA encoding format */
bool encoding_format_enable;
/** The minimum pulse length required for a pulse to be accepted by the IrDA receiver */
uint8_t receive_pulse_length;
#endif
#ifdef FEATURE_USART_LIN_SLAVE
/** Enable LIN Slave Support */
bool lin_slave_enable;
#endif
#ifdef FEATURE_USART_LIN_MASTER
/** LIN node type */
enum lin_node_type lin_node;
/** LIN master header delay */
enum lin_master_header_delay lin_header_delay;
/** LIN Master Break Length */
enum lin_master_break_length lin_break_length;
#endif
#ifdef FEATURE_USART_START_FRAME_DECTION
/** Enable start of frame dection */
bool start_frame_detection_enable;
#endif
#ifdef FEATURE_USART_ISO7816
/** Enable ISO7816 for smart card interfacing */
struct iso7816_config_t iso7816_config;
#endif
#ifdef FEATURE_USART_RS485
/** RS485 guard time */
enum rs485_guard_time rs485_guard_time;
#endif
#ifdef FEATURE_USART_COLLISION_DECTION
/** Enable collision dection */
bool collision_detection_enable;
#endif
/** USART baudrate */
uint32_t baudrate;
/** Enable receiver */
bool receiver_enable;
/** Enable transmitter */
bool transmitter_enable;
/** USART Clock Polarity.
* If true, data changes on falling XCK edge and
* is sampled at rising edge.
* If false, data changes on rising XCK edge and
* is sampled at falling edge.
* */
bool clock_polarity_inverted;
/** States whether to use the external clock applied to the XCK pin.
* In synchronous mode the shift register will act directly on the XCK clock.
* In asynchronous mode the XCK will be the input to the USART hardware module.
*/
bool use_external_clock;
/** External clock frequency in synchronous mode.
* This must be set if \c use_external_clock is true. */
uint32_t ext_clock_freq;
/** If true the USART will be kept running in Standby sleep mode */
bool run_in_standby;
/** GCLK generator source */
enum gclk_generator generator_source;
/** PAD0 pinmux.
*
* If current USARTx has several alternative multiplexing I/O pins for PAD0, then
* only one peripheral multiplexing I/O can be enabled for current USARTx PAD0
* function. Make sure that no other alternative multiplexing I/O is associated
* with the same USARTx PAD0.
*/
uint32_t pinmux_pad0;
/** PAD1 pinmux.
*
* If current USARTx has several alternative multiplexing I/O pins for PAD1, then
* only one peripheral multiplexing I/O can be enabled for current USARTx PAD1
* function. Make sure that no other alternative multiplexing I/O is associated
* with the same USARTx PAD1.
*/
uint32_t pinmux_pad1;
/** PAD2 pinmux.
*
* If current USARTx has several alternative multiplexing I/O pins for PAD2, then
* only one peripheral multiplexing I/O can be enabled for current USARTx PAD2
* function. Make sure that no other alternative multiplexing I/O is associated
* with the same USARTx PAD2.
*/
uint32_t pinmux_pad2;
/** PAD3 pinmux.
*
* If current USARTx has several alternative multiplexing I/O pins for PAD3, then
* only one peripheral multiplexing I/O can be enabled for current USARTx PAD3
* function. Make sure that no other alternative multiplexing I/O is associated
* with the same USARTx PAD3.
*/
uint32_t pinmux_pad3;
};
#if USART_CALLBACK_MODE == true
/**
* \brief USART module instance
*
* Forward Declaration for the device instance.
*/
struct usart_module;
/**
* \brief USART callback type
*
* Type of the callback functions.
*/
typedef void (*usart_callback_t)(struct usart_module *const module);
#endif
/**
* \brief SERCOM USART driver software device instance structure.
*
* SERCOM USART driver software instance structure, used to retain software
* state information of an associated hardware module instance.
*
* \note The fields of this structure should not be altered by the user
* application; they are reserved for module-internal use only.
*/
struct usart_module {
#if !defined(__DOXYGEN__)
/** Pointer to the hardware instance */
Sercom *hw;
/** Module lock */
volatile bool locked;
/** Character size of the data being transferred */
enum usart_character_size character_size;
/** Receiver enabled */
bool receiver_enabled;
/** Transmitter enabled */
bool transmitter_enabled;
#ifdef FEATURE_USART_LIN_SLAVE
/** LIN Slave Support enabled */
bool lin_slave_enabled;
#endif
#ifdef FEATURE_USART_START_FRAME_DECTION
/** Start of frame dection enabled */
bool start_frame_detection_enabled;
#endif
#ifdef FEATURE_USART_ISO7816
/** ISO7816 mode enable */
bool iso7816_mode_enabled;
#endif
# if USART_CALLBACK_MODE == true
/** Array to store callback function pointers in */
usart_callback_t callback[USART_CALLBACK_N];
/** Buffer pointer to where the next received character will be put */
volatile uint8_t *rx_buffer_ptr;
/** Buffer pointer to where the next character will be transmitted from
**/
volatile uint8_t *tx_buffer_ptr;
/** Remaining characters to receive */
volatile uint16_t remaining_rx_buffer_length;
/** Remaining characters to transmit */
volatile uint16_t remaining_tx_buffer_length;
/** Bit mask for callbacks registered */
uint8_t callback_reg_mask;
/** Bit mask for callbacks enabled */
uint8_t callback_enable_mask;
/** Holds the status of the ongoing or last read operation */
volatile enum status_code rx_status;
/** Holds the status of the ongoing or last write operation */
volatile enum status_code tx_status;
# endif
#endif
};
/**
* \name Lock/Unlock
* @{
*/
/**
* \brief Attempt to get lock on driver instance
*
* This function checks the instance's lock, which indicates whether or not it
* is currently in use, and sets the lock if it was not already set.
*
* The purpose of this is to enable exclusive access to driver instances, so
* that, e.g., transactions by different services will not interfere with each
* other.
*
* \param[in,out] module Pointer to the driver instance to lock
*
* \retval STATUS_OK If the module was locked
* \retval STATUS_BUSY If the module was already locked
*/
static inline enum status_code usart_lock(
struct usart_module *const module)
{
enum status_code status;
system_interrupt_enter_critical_section();
if (module->locked) {
status = STATUS_BUSY;
} else {
module->locked = true;
status = STATUS_OK;
}
system_interrupt_leave_critical_section();
return status;
}
/**
* \brief Unlock driver instance
*
* This function clears the instance lock, indicating that it is available for
* use.
*
* \param[in,out] module Pointer to the driver instance to lock
*
*/
static inline void usart_unlock(struct usart_module *const module)
{
module->locked = false;
}
/** @} */
/**
* \brief Check if peripheral is busy syncing registers across clock domains
*
* Return peripheral synchronization status. If doing a non-blocking
* implementation this function can be used to check the sync state and hold of
* any new actions until sync is complete. If this function is not run; the
* functions will block until the sync has completed.
*
* \param[in] module Pointer to peripheral module
*
* \return Peripheral sync status.
*
* \retval true Peripheral is busy syncing
* \retval false Peripheral is not busy syncing and can be read/written without
* stalling the bus
*/
static inline bool usart_is_syncing(
const struct usart_module *const module)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
SercomUsart *const usart_hw = &(module->hw->USART);
#ifdef FEATURE_USART_SYNC_SCHEME_V2
return (usart_hw->SYNCBUSY.reg);
#else
return (usart_hw->STATUS.reg & SERCOM_USART_STATUS_SYNCBUSY);
#endif
}
#if !defined (__DOXYGEN__)
/**
* \internal
* Waits until synchronization is complete
*/
static inline void _usart_wait_for_sync(
const struct usart_module *const module)
{
/* Sanity check */
Assert(module);
while (usart_is_syncing(module)) {
/* Wait until the synchronization is complete */
}
}
#endif
/**
* \brief Initializes the device to predefined defaults
*
* Initialize the USART device to predefined defaults:
* - 8-bit asynchronous USART
* - No parity
* - One stop bit
* - 9600 baud
* - Transmitter enabled
* - Receiver enabled
* - GCLK generator 0 as clock source
* - Default pin configuration
*
* The configuration struct will be updated with the default
* configuration.
*
* \param[in,out] config Pointer to configuration struct
*/
static inline void usart_get_config_defaults(
struct usart_config *const config)
{
/* Sanity check arguments */
Assert(config);
/* Set default config in the config struct */
config->data_order = USART_DATAORDER_LSB;
config->transfer_mode = USART_TRANSFER_ASYNCHRONOUSLY;
config->parity = USART_PARITY_NONE;
config->stopbits = USART_STOPBITS_1;
config->character_size = USART_CHARACTER_SIZE_8BIT;
config->baudrate = 9600;
config->receiver_enable = true;
config->transmitter_enable = true;
config->clock_polarity_inverted = false;
config->use_external_clock = false;
config->ext_clock_freq = 0;
config->mux_setting = USART_RX_1_TX_2_XCK_3;
config->run_in_standby = false;
config->generator_source = GCLK_GENERATOR_0;
config->pinmux_pad0 = PINMUX_DEFAULT;
config->pinmux_pad1 = PINMUX_DEFAULT;
config->pinmux_pad2 = PINMUX_DEFAULT;
config->pinmux_pad3 = PINMUX_DEFAULT;
#ifdef FEATURE_USART_OVER_SAMPLE
config->sample_adjustment = USART_SAMPLE_ADJUSTMENT_7_8_9;
config->sample_rate = USART_SAMPLE_RATE_16X_ARITHMETIC;
#endif
#ifdef FEATURE_USART_LIN_SLAVE
config->lin_slave_enable = false;
#endif
#ifdef FEATURE_USART_LIN_MASTER
config->lin_node = LIN_INVALID_MODE;
config->lin_header_delay = LIN_MASTER_HEADER_DELAY_0;
config->lin_break_length = LIN_MASTER_BREAK_LENGTH_13_BIT;
#endif
#ifdef FEATURE_USART_IMMEDIATE_BUFFER_OVERFLOW_NOTIFICATION
config->immediate_buffer_overflow_notification = false;
#endif
#ifdef FEATURE_USART_START_FRAME_DECTION
config->start_frame_detection_enable = false;
#endif
#ifdef FEATURE_USART_IRDA
config->encoding_format_enable = false;
config->receive_pulse_length = 19;
#endif
#ifdef FEATURE_USART_ISO7816
config->iso7816_config.enabled = false;
config->iso7816_config.guard_time = ISO7816_GUARD_TIME_2_BIT;
config->iso7816_config.protocol_t = ISO7816_PROTOCOL_T_0;
config->iso7816_config.enable_inverse = false;
config->iso7816_config.inhibit_nack = ISO7816_INHIBIT_NACK_DISABLE;
config->iso7816_config.successive_recv_nack = ISO7816_SUCCESSIVE_RECV_NACK_DISABLE;
config->iso7816_config.max_iterations = 7;
#endif
#ifdef FEATURE_USART_COLLISION_DECTION
config->collision_detection_enable = false;
#endif
#ifdef FEATURE_USART_RS485
config->rs485_guard_time = RS485_GUARD_TIME_0_BIT;
#endif
}
enum status_code usart_init(
struct usart_module *const module,
Sercom *const hw,
const struct usart_config *const config);
/**
* \brief Enable the module
*
* Enables the USART module.
*
* \param[in] module Pointer to USART software instance struct
*/
static inline void usart_enable(
const struct usart_module *const module)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
#if USART_CALLBACK_MODE == true
/* Enable Global interrupt for module */
system_interrupt_enable(_sercom_get_interrupt_vector(module->hw));
#endif
/* Wait until synchronization is complete */
_usart_wait_for_sync(module);
/* Enable USART module */
usart_hw->CTRLA.reg |= SERCOM_USART_CTRLA_ENABLE;
}
/**
* \brief Disable module
*
* Disables the USART module.
*
* \param[in] module Pointer to USART software instance struct
*/
static inline void usart_disable(
const struct usart_module *const module)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
#if USART_CALLBACK_MODE == true
/* Disable Global interrupt for module */
system_interrupt_disable(_sercom_get_interrupt_vector(module->hw));
#endif
/* Wait until synchronization is complete */
_usart_wait_for_sync(module);
/* Disable USART module */
usart_hw->CTRLA.reg &= ~SERCOM_USART_CTRLA_ENABLE;
}
/**
* \brief Resets the USART module
*
* Disables and resets the USART module.
*
* \param[in] module Pointer to the USART software instance struct
*/
static inline void usart_reset(
const struct usart_module *const module)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
usart_disable(module);
/* Wait until synchronization is complete */
_usart_wait_for_sync(module);
/* Reset module */
usart_hw->CTRLA.reg = SERCOM_USART_CTRLA_SWRST;
}
/**
* \name Writing and Reading
* @{
*/
enum status_code usart_write_wait(
struct usart_module *const module,
const uint16_t tx_data);
enum status_code usart_read_wait(
struct usart_module *const module,
uint16_t *const rx_data);
enum status_code usart_write_buffer_wait(
struct usart_module *const module,
const uint8_t *tx_data,
uint16_t length);
enum status_code usart_read_buffer_wait(
struct usart_module *const module,
uint8_t *rx_data,
uint16_t length);
/** @} */
/**
* \name Enabling/Disabling Receiver and Transmitter
* @{
*/
/**
* \brief Enable Transceiver
*
* Enable the given transceiver. Either RX or TX.
*
* \param[in] module Pointer to USART software instance struct
* \param[in] transceiver_type Transceiver type
*/
static inline void usart_enable_transceiver(
struct usart_module *const module,
enum usart_transceiver_type transceiver_type)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
/* Wait until synchronization is complete */
_usart_wait_for_sync(module);
switch (transceiver_type) {
case USART_TRANSCEIVER_RX:
/* Enable RX */
usart_hw->CTRLB.reg |= SERCOM_USART_CTRLB_RXEN;
module->receiver_enabled = true;
break;
case USART_TRANSCEIVER_TX:
/* Enable TX */
usart_hw->CTRLB.reg |= SERCOM_USART_CTRLB_TXEN;
module->transmitter_enabled = true;
break;
}
_usart_wait_for_sync(module);
}
/**
* \brief Disable Transceiver
*
* Disable the given transceiver (RX or TX).
*
* \param[in] module Pointer to USART software instance struct
* \param[in] transceiver_type Transceiver type
*/
static inline void usart_disable_transceiver(
struct usart_module *const module,
enum usart_transceiver_type transceiver_type)
{
/* Sanity check arguments */
Assert(module);
Assert(module->hw);
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
/* Wait until synchronization is complete */
_usart_wait_for_sync(module);
switch (transceiver_type) {
case USART_TRANSCEIVER_RX:
/* Disable RX */
usart_hw->CTRLB.reg &= ~SERCOM_USART_CTRLB_RXEN;
module->receiver_enabled = false;
break;
case USART_TRANSCEIVER_TX:
/* Disable TX */
usart_hw->CTRLB.reg &= ~SERCOM_USART_CTRLB_TXEN;
module->transmitter_enabled = false;
break;
}
}
/** @} */
#ifdef FEATURE_USART_LIN_MASTER
/**
* \name LIN Master Command and Status
* @{
*/
/**
* \brief Sending LIN command.
*
* Sending LIN command.
*
* \param[in] module Pointer to USART software instance struct
* \param[in] cmd Cammand type
*/
static inline void lin_master_send_cmd(
struct usart_module *const module,
enum lin_master_cmd cmd)
{
SercomUsart *const usart_hw = &(module->hw->USART);
_usart_wait_for_sync(module);
usart_hw->CTRLB.reg |= cmd;
}
/**
* \brief Get LIN transmission status
*
* Get LIN transmission status.
*
* \param[in] module Pointer to USART software instance struct
*
* \return Status of LIN master transmission.
* \retval true Data transmission completed
* \retval false Transmission is ongoing
*/
static inline bool lin_master_transmission_status(struct usart_module *const module)
{
SercomUsart *const usart_hw = &(module->hw->USART);
return ((usart_hw->STATUS.reg & SERCOM_USART_STATUS_TXE)? true:false);
}
/** @} */
#endif
#ifdef __cplusplus
}
#endif
/** @} */
/**
* \page asfdoc_sam0_sercom_usart_extra Extra Information for SERCOM USART Driver
*
* \section asfdoc_sam0_sercom_usart_extra_acronyms Acronyms
*
* Below is a table listing the acronyms used in this module, along with their
* intended meanings.
*
* <table>
* <tr>
* <th>Acronym</th>
* <th>Description</th>
* </tr>
* <tr>
* <td>SERCOM</td>
* <td>Serial Communication Interface</td>
* </tr>
* <tr>
* <td>USART</td>
* <td>Universal Synchronous and Asynchronous Serial Receiver and Transmitter</td>
* </tr>
* <tr>
* <td>LSB</td>
* <td>Least Significant Bit</td>
* </tr>
* <tr>
* <td>MSB</td>
* <td>Most Significant Bit</td>
* </tr>
* <tr>
* <td>DMA</td>
* <td>Direct Memory Access</td>
* </tr>
* </table>
*
*
* \section asfdoc_sam0_sercom_usart_extra_dependencies Dependencies
* This driver has the following dependencies:
*
* - \ref asfdoc_sam0_system_pinmux_group "System Pin Multiplexer Driver"
* - \ref asfdoc_sam0_system_clock_group "System clock configuration"
*
*
* \section asfdoc_sam0_sercom_usart_extra_errata Errata
* There are no errata related to this driver.
*
*
* \section asfdoc_sam0_sercom_usart_extra_history Module History
* An overview of the module history is presented in the table below, with
* details on the enhancements and fixes made to the module since its first
* release. The current version of this corresponds to the newest version in
* the table.
*
* <table>
* <tr>
* <th>Changelog</th>
* </tr>
* <tr>
* <td>Added new feature as below:
* \li ISO7816
* </tr>
* <tr>
* <td>Added new features as below:
* \li LIN master
* \li RS485
* </tr>
* <tr>
* <td>Added new features as below:
* \li Oversample
* \li Buffer overflow notification
* \li Irda
* \li Lin slave
* \li Start frame detection
* \li Hardware flow control
* \li Collision detection
* \li DMA support </td>
* </tr>
* <tr>
* <td>\li Added new \c transmitter_enable and \c receiver_enable Boolean
* values to \c struct usart_config
* \li Altered \c usart_write_* and usart_read_* functions to abort with
* an error code if the relevant transceiver is not enabled
* \li Fixed \c usart_write_buffer_wait() and \c usart_read_buffer_wait()
* not aborting correctly when a timeout condition occurs</td>
* </tr>
* <tr>
* <td>Initial Release</td>
* </tr>
* </table>
*/
/**
* \page asfdoc_sam0_sercom_usart_exqsg Examples for SERCOM USART Driver
*
* This is a list of the available Quick Start guides (QSGs) and example
* applications for \ref asfdoc_sam0_sercom_usart_group. QSGs are simple examples with
* step-by-step instructions to configure and use this driver in a selection of
* use cases. Note that a QSG can be compiled as a standalone application or be
* added to the user application.
*
* - \subpage asfdoc_sam0_sercom_usart_basic_use_case
* \if USART_CALLBACK_MODE
* - \subpage asfdoc_sam0_sercom_usart_callback_use_case
* \endif
* - \subpage asfdoc_sam0_sercom_usart_dma_use_case
* - \subpage asfdoc_sam0_sercom_usart_lin_use_case
*/
/**
* \page asfdoc_sam0_sercom_usart_mux_settings SERCOM USART MUX Settings
*
* The following lists the possible internal SERCOM module pad function
* assignments, for the four SERCOM pads when in USART mode. Note that this is
* in addition to the physical GPIO pin MUX of the device, and can be used in
* conjunction to optimize the serial data pin-out.
*
* When TX and RX are connected to the same pin, the USART will operate in
* half-duplex mode if both one transmitter and several receivers are enabled.
*
* \note When RX and XCK are connected to the same pin, the receiver must not
* be enabled if the USART is configured to use an external clock.
*
*
* <table>
* <tr>
* <th>MUX/Pad</th>
* <th>PAD 0</th>
* <th>PAD 1</th>
* <th>PAD 2</th>
* <th>PAD 3</th>
* </tr>
* <tr>
* <td>RX_0_TX_0_XCK_1</td>
* <td>TX / RX</td>
* <td>XCK</td>
* <td>-</td>
* <td>-</td>
* </tr>
* <tr>
* <td>RX_0_TX_2_XCK_3</td>
* <td>RX</td>
* <td>-</td>
* <td>TX</td>
* <td>XCK</td>
* </tr>
* <tr>
* <td>RX_1_TX_0_XCK_1</td>
* <td>TX</td>
* <td>RX / XCK</td>
* <td>-</td>
* <td>-</td>
* </tr>
* <tr>
* <td>RX_1_TX_2_XCK_3</td>
* <td>-</td>
* <td>RX</td>
* <td>TX</td>
* <td>XCK</td>
* </tr>
* <tr>
* <td>RX_2_TX_0_XCK_1</td>
* <td>TX</td>
* <td>XCK</td>
* <td>RX</td>
* <td>-</td>
* </tr>
* <tr>
* <td>RX_2_TX_2_XCK_3</td>
* <td>-</td>
* <td>-</td>
* <td>TX / RX</td>
* <td>XCK</td>
* </tr>
* <tr>
* <td>RX_3_TX_0_XCK_1</td>
* <td>TX</td>
* <td>XCK</td>
* <td>-</td>
* <td>RX</td>
* </tr>
* <tr>
* <td>RX_3_TX_2_XCK_3</td>
* <td>-</td>
* <td>-</td>
* <td>TX</td>
* <td>RX / XCK</td>
* </tr>
* </table>
*
* \page asfdoc_sam0_sercom_usart_document_revision_history Document Revision History
*
* <table>
* <tr>
* <th>Doc. Rev.</td>
* <th>Date</td>
* <th>Comments</td>
* </tr>
* <tr>
* <td>42118F</td>
* <td>12/2015</td>
* <td>Added support for SAM L21/L22, SAM DA1, SAM D09, SAMR30 and SAM C20/C21</td>
* </tr>
* <tr>
* <td>42118E</td>
* <td>12/2014</td>
* <td>Added support for SAM R21 and SAM D10/D11</td>
* </tr>
* <tr>
* <td>42118D</td>
* <td>01/2014</td>
* <td>Added support for SAM D21</td>
* </tr>
* <tr>
* <td>42118C</td>
* <td>10/2013</td>
* <td>Replaced the pad multiplexing documentation with a condensed table</td>
* </tr>
* <tr>
* <td>42118B</td>
* <td>06/2013</td>
* <td>Corrected documentation typos</td>
* </tr>
* <tr>
* <td>42118A</td>
* <td>06/2013</td>
* <td>Initial release</td>
* </tr>
* </table>
*/
#endif /* USART_H_INCLUDED */