uart_half_duplex.h
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/*
* Copyright (C) 2017 Inria
*
* This file is subject to the terms and conditions of the GNU Lesser General
* Public License v2.1. See the file LICENSE in the top level directory for more
* details.
*/
/**
* @defgroup drivers_uart_half_duplex half-duplex UART Driver
* @ingroup drivers_actuators
*
* This module contains drivers for UART half-duplex communication bus.
* It needs to manage the communication direction by enabling or disabling TX.
*
* @{
*
* @file
* @brief Interface definition for half-duplex UART driver
*
* @author Loïc Dauphin <loic.dauphin@inria.fr>
*/
#ifndef UART_HALF_DUPLEX_H
#define UART_HALF_DUPLEX_H
#include <stdlib.h>
#include "periph/uart.h"
#ifdef __cplusplus
extern "C" {
#endif
#ifndef UART_HALF_DUPLEX_DEFAULT_TIMEOUT_US
#define UART_HALF_DUPLEX_DEFAULT_TIMEOUT_US (20000LU) /**< Default recv timeout (in microseconds) */
#endif
/**
* @brief half-duplex UART direction management method type
*/
typedef struct {
void (*init)(uart_t); /**< function initializing direction management method */
void (*enable_tx)(uart_t); /**< function enabling TX */
void (*disable_tx)(uart_t); /**< function disabling TX */
} uart_half_duplex_dir_t;
#define UART_HALF_DUPLEX_DIR_NONE { NULL, NULL, NULL } /**< Don't manage direction */
/**
* @brief Configuration for half-duplex UART
*/
typedef struct {
uart_t uart; /**< the half-duplex UART bus to use */
uint32_t baudrate; /**< the baudrate to use */
uart_half_duplex_dir_t dir; /**< the direction management method */
} uart_half_duplex_params_t;
/**
* @brief Descriptor struct for half-duplex UART
*/
typedef struct {
uint8_t *buffer; /**< the buffer used for TX and RX */
size_t size; /**< the number of available elements for TX/RX */
size_t buffer_max_size; /**< the buffer size */
uint32_t timeout_us; /**< the maximum duration (in microseconds) for waiting data */
uart_half_duplex_params_t params; /**< the half-duplex UART configuration */
} uart_half_duplex_t;
/**
* @brief Possible UART_HALF_DUPLEX return values
*/
enum {
UART_HALF_DUPLEX_OK = UART_OK, /**< everything in order */
UART_HALF_DUPLEX_NODEV = UART_NODEV, /**< invalid UART device given */
UART_HALF_DUPLEX_NOBAUD = UART_NOBAUD, /**< given baudrate is not applicable */
UART_HALF_DUPLEX_INTERR = UART_INTERR, /**< all other internal errors */
UART_HALF_DUPLEX_NOMODE = UART_NOMODE, /**< given mode is not applicable */
UART_HALF_DUPLEX_NOBUFF = -5 /**< invalid buffer given */
};
/**
* @brief Initialize the half-duplex UART bus to communicate with devices
*
* @param[out] dev the device
* @param[in] buffer the buffer used for TX and RX
* @param[in] buffer_max_size the buffer size
* @param[in] params the initialization parameters
*
* @return UART_HALF_DUPLEX_OK if everything is in order
* @return UART_HALF_DUPLEX_NODEV if invalid UART device was given
* @return UART_HALF_DUPLEX_NOBAUD if given baudrate is not applicable
* @return UART_HALF_DUPLEX_INTERR if an other internal error occured
* @return UART_HALF_DUPLEX_NOMODE if the given mode is not applicable
* @return UART_HALF_DUPLEX_NOBUFF if an invalid buffer was given
*/
int uart_half_duplex_init(uart_half_duplex_t *dev, uint8_t *buffer, size_t buffer_max_size, const uart_half_duplex_params_t *params);
/**
* @brief Set the half-duplex UART bus in TX mode
*
* @param[in] dev the device
*/
static inline void uart_half_duplex_set_tx(uart_half_duplex_t *dev)
{
dev->size = dev->buffer_max_size;
}
/**
* @brief Set the half-duplex UART bus in RX mode
*
* @param[in] dev the device
*/
static inline void uart_half_duplex_set_rx(uart_half_duplex_t *dev)
{
dev->size = 0;
}
/**
* @brief Send the data contained in the driver's buffer
*
* @param[in] dev the device
* @param[in] size the number of characters to send
*
* @return the number of characters actually sent
*/
size_t uart_half_duplex_send(const uart_half_duplex_t *dev, size_t size);
/**
* @brief Recv data an fill the driver's buffer
*
* @param[in] dev the device
* @param[in] size the number of characters to receive
*
* @return the number of characters actually received
*/
size_t uart_half_duplex_recv(const uart_half_duplex_t *dev, size_t size);
#ifdef __cplusplus
}
#endif
#endif /* UART_HALF_DUPLEX_H */
/** @} */