@DOC_TITLE@ Xmega Application Note usart_example_polled.c File ReferenceDetailed Description XMEGA polled USART driver example source. This file contains an example application that demonstrates the polled USART driver. The code example sends all values between 0 and 255 and checks that the values received are equal to the values sent. It can be tested, using a loop-back wire between I/O pins PC2 and PC3. Application note:AVR1307: Using the XMEGA USART DocumentationFor comprehensive code documentation, supported compilers, compiler settings and supported devices see readme.html Author:Atmel Corporation: http://www.atmel.com Support email: [e-mail] Revision1694 Date2008-07-29 14:21:58 +0200 (ti, 29 jul 2008) Copyright (c) 2008, Atmel Corporation All rights reserved. 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. THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 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. Definition in file usart_example_polled.c. #include "usart_driver.h" #include "avr_compiler.h" Include dependency graph for usart_example_polled.c: Go to the source code of this file. Defines #define USART   USARTC0 Functions int main (void)  Example application. Variables bool success Define Documentation #define USART   USARTC0 Define that selects the Usart used in example. Definition at line 57 of file usart_example_polled.c. Function Documentation int main ( void   )  Example application. Example applicaton. This example configures USARTC0 for with the parameters: 8 bit character sizeNo parity1 stop bit9600 Baud This function then sends the values 0-255 and tests if the received data is equal to the sent data. The code can be tested by connecting PC3 to PC2. If the variable 'success' is true at the end of the function, the values have been successfully sent and received. Definition at line 77 of file usart_example_polled.c. References success, USART, USART_Baudrate_Set, USART_Format_Set, USART_GetChar, USART_IsRXComplete, USART_IsTXDataRegisterEmpty, USART_PutChar, USART_Rx_Disable, USART_Rx_Enable, USART_Tx_Disable, and USART_Tx_Enable. 00078 { 00079 00080 /* Variable used to send and receive data. */ 00081 uint8_t sendData; 00082 uint8_t receivedData; 00083 00084 /* This PORT setting is only valid to USARTC0 if other USARTs is used a 00085 * different PORT and/or pins is used. */ 00086 /* PIN3 (TXD0) as output. */ 00087 PORTC.DIRSET = PIN3_bm; 00088 00089 /* PC2 (RXD0) as input. */ 00090 PORTC.DIRCLR = PIN2_bm; 00091 00092 /* USARTC0, 8 Data bits, No Parity, 1 Stop bit. */ 00093 USART_Format_Set(&USART, USART_CHSIZE_8BIT_gc, USART_PMODE_DISABLED_gc, false); 00094 00095 /* Set Baudrate to 9600 bps: 00096 * Use the default I/O clock fequency that is 2 MHz. 00097 * Do not use the baudrate scale factor 00098 * 00099 * Baudrate select = (1/(16*(((I/O clock frequency)/Baudrate)-1) 00100 * = 12 00101 */ 00102 USART_Baudrate_Set(&USART, 12 , 0); 00103 00104 /* Enable both RX and TX. */ 00105 USART_Rx_Enable(&USART); 00106 USART_Tx_Enable(&USART); 00107 00108 00109 /* Assume that everything is OK. */ 00110 success = true; 00111 /* Send data from 255 down to 0*/ 00112 sendData = 255; 00113 while(sendData) { 00114 /* Send one char. */ 00115 do{ 00116 /* Wait until it is possible to put data into TX data register. 00117 * NOTE: If TXDataRegister never becomes empty this will be a DEADLOCK. */ 00118 }while(!USART_IsTXDataRegisterEmpty(&USART)); 00119 USART_PutChar(&USART, sendData); 00120 00121 uint16_t timeout = 1000; 00122 /* Receive one char. */ 00123 do{ 00124 /* Wait until data received or a timeout.*/ 00125 timeout--; 00126 }while(!USART_IsRXComplete(&USART) && timeout!=0); 00127 receivedData = USART_GetChar(&USART); 00128 00129 /* Check the received data. */ 00130 if (receivedData != sendData){ 00131 success = false; 00132 } 00133 sendData--; 00134 } 00135 00136 /* Disable both RX and TX. */ 00137 USART_Rx_Disable(&USART); 00138 USART_Tx_Disable(&USART); 00139 00140 /* If success the program ends up inside the if statment.*/ 00141 if(success){ 00142 while(true); 00143 }else{ 00144 while(true); 00145 } 00146 } Variable Documentation bool success Success variable, used to test driver. Definition at line 61 of file usart_example_polled.c. @DOC_TITLE@ Generated on Wed Nov 5 10:23:28 2008 for AVRxxxx Application note title by 1.5.5