1 /* 2 * Author: Thomas Ingleby <thomas.c.ingleby (at) intel.com> 3 * Contributions: Jon Trulson <jtrulson (at) ics.com> 4 * Brendan Le Foll <brendan.le.foll (at) intel.com> 5 * Copyright (c) 2014 - 2015 Intel Corporation 6 * 7 * Permission is hereby granted, free of charge, to any person obtaining 8 * a copy of this software and associated documentation files (the 9 * "Software"), to deal in the Software without restriction, including 10 * without limitation the rights to use, copy, modify, merge, publish, 11 * distribute, sublicense, and/or sell copies of the Software, and to 12 * permit persons to whom the Software is furnished to do so, subject to 13 * the following conditions: 14 * 15 * The above copyright notice and this permission notice shall be 16 * included in all copies or substantial portions of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 21 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 22 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 23 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 24 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 25 */ 26 27 #pragma once 28 29 /** 30 * @file 31 * @brief UART module 32 * 33 * UART is the Universal asynchronous receiver/transmitter interface to 34 * libmraa. It allows the exposure of UART pins on supported boards. 35 * With functionality to expand at a later date. 36 * 37 * @snippet uart.c Interesting 38 */ 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 #include <stdio.h> 45 46 #include "common.h" 47 48 typedef struct _uart* mraa_uart_context; 49 50 /** 51 * Initialise uart_context, uses board mapping 52 * 53 * @param uart the index of the uart set to use 54 * @return uart context or NULL 55 */ 56 mraa_uart_context mraa_uart_init(int uart); 57 58 /** 59 * Initialise a raw uart_context. No board setup. 60 * 61 * @param path for example "/dev/ttyS0" 62 * @return uart context or NULL 63 */ 64 mraa_uart_context mraa_uart_init_raw(const char* path); 65 66 /** 67 * Flush the outbound data. 68 * Blocks until complete. 69 * 70 * @param dev The UART context 71 * @return Result of operation 72 */ 73 mraa_result_t mraa_uart_flush(mraa_uart_context dev); 74 75 /** 76 * Set the baudrate. 77 * Takes an int and will attempt to decide what baudrate is 78 * to be used on the UART hardware. 79 * 80 * @param dev The UART context 81 * @param baud unsigned int of baudrate i.e. 9600 82 * @return Result of operation 83 */ 84 mraa_result_t mraa_uart_set_baudrate(mraa_uart_context dev, unsigned int baud); 85 86 /** 87 * Set the transfer mode 88 * For example setting the mode to 8N1 would be 89 * "mraa_uart_set_mode(dev, 8,MRAA_UART_PARITY_NONE , 1)" 90 * 91 * @param dev The UART context 92 * @param bytesize data bits 93 * @param parity Parity bit setting 94 * @param stopbits stop bits 95 * @return Result of operation 96 */ 97 mraa_result_t mraa_uart_set_mode(mraa_uart_context dev, int bytesize, mraa_uart_parity_t parity, int stopbits); 98 99 /** 100 * Set the flowcontrol 101 * 102 * @param dev The UART context 103 * @param xonxoff XON/XOFF Software flow control. 104 * @param rtscts RTS/CTS out of band hardware flow control 105 * @return Result of operation 106 */ 107 mraa_result_t mraa_uart_set_flowcontrol(mraa_uart_context dev, mraa_boolean_t xonxoff, mraa_boolean_t rtscts); 108 109 /** 110 * Set the timeout for read and write operations 111 * <= 0 will disable that timeout 112 * 113 * @param dev The UART context 114 * @param read read timeout 115 * @param write write timeout 116 * @param interchar inbetween char timeout 117 * @return Result of operation 118 */ 119 mraa_result_t mraa_uart_set_timeout(mraa_uart_context dev, int read, int write, int interchar); 120 121 /** 122 * Get Char pointer with tty device path within Linux 123 * For example. Could point to "/dev/ttyS0" 124 * 125 * @param dev uart context 126 * @return char pointer of device path 127 */ 128 const char* mraa_uart_get_dev_path(mraa_uart_context dev); 129 130 /** 131 * Destroy a mraa_uart_context 132 * 133 * @param dev uart context 134 * @return mraa_result_t 135 */ 136 mraa_result_t mraa_uart_stop(mraa_uart_context dev); 137 138 /** 139 * Read bytes from the device into a buffer 140 * 141 * @param dev uart context 142 * @param buf buffer pointer 143 * @param length maximum size of buffer 144 * @return the number of bytes read, or -1 if an error occurred 145 */ 146 int mraa_uart_read(mraa_uart_context dev, char* buf, size_t length); 147 148 /** 149 * Write bytes in buffer to a device 150 * 151 * @param dev uart context 152 * @param buf buffer pointer 153 * @param length maximum size of buffer 154 * @return the number of bytes written, or -1 if an error occurred 155 */ 156 int mraa_uart_write(mraa_uart_context dev, const char* buf, size_t length); 157 158 /** 159 * Check to see if data is available on the device for reading 160 * 161 * @param dev uart context 162 * @param millis number of milliseconds to wait, or 0 to return immediately 163 * @return 1 if there is data available to read, 0 otherwise 164 */ 165 mraa_boolean_t mraa_uart_data_available(mraa_uart_context dev, unsigned int millis); 166 167 #ifdef __cplusplus 168 } 169 #endif 170
