uart.rar_distant7fo

//***************************************************************************** // // uart_polled.c - Example demonstrating UART polled I/O. // // Copyright (c) 2010-2011 Texas Instruments Incorporated. All rights reserved. // Software License Agreement // // Texas Instruments (TI) is supplying this software for use solely and // exclusively on TI's microcontroller products. The software is owned by // TI and/or its suppliers, and is protected under applicable copyright // laws. You may not combine this software with "viral" open-source // software in order to form a larger program. // // THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS. // NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT // NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY // CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL // DAMAGES, FOR ANY REASON WHATSOEVER. // // This is part of revision 7243 of the Stellaris Firmware Development Package. // //***************************************************************************** #include "inc/hw_memmap.h" #include "inc/hw_types.h" #include "driverlib/sysctl.h" #include "driverlib/uart.h" #include "driverlib/gpio.h" //***************************************************************************** // //! \addtogroup uart_examples_list //! <h1>UART Polled I/O (uart_polled)</h1> //! //! This example shows how to set up the UART and use polled I/O methods //! for transmitting and receiving UART data. The example receives characters //! from UART0 and retransmits the same character using UART0. It can be //! tested by using a serial terminal program on a host computer. This //! example will echo every character that is type until the return/enter key //! is pressed. //! //! This example uses the following peripherals and I/O signals. You must //! review these and change as needed for your own board: //! - UART0 peripheral //! - GPIO Port A peripheral (for UART0 pins) //! - UART0RX - PA0 //! - UART0TX - PA1 //! // //***************************************************************************** //***************************************************************************** // // Configure the UART and perform reads and writes using polled I/O. // //***************************************************************************** int main(void) { char cThisChar; // // Set the clocking to run directly from the external crystal/oscillator. // TODO: The SYSCTL_XTAL_ value must be changed to match the value of the // crystal on your board. // SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ); // // Enable the peripherals used by this example. // The UART itself needs to be enabled, as well as the GPIO port // containing the pins that will be used. // SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0); SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA); // // Configure the GPIO pin muxing for the UART function. // This is only necessary if your part supports GPIO pin function muxing. // Study the data sheet to see which functions are allocated per pin. // TODO: change this to select the port/pin you are using // GPIOPinConfigure(GPIO_PA0_U0RX); GPIOPinConfigure(GPIO_PA1_U0TX); // // Since GPIO A0 and A1 are used for the UART function, they must be // configured for use as a peripheral function (instead of GPIO). // TODO: change this to match the port/pin you are using // GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1); // // Configure the UART for 115,200, 8-N-1 operation. // This function uses SysCtlClockGet() to get the system clock // frequency. This could be also be a variable or hard coded value // instead of a function call. // UARTConfigSetExpClk(UART0_BASE, SysCtlClockGet(), 115200, (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE | UART_CONFIG_PAR_NONE)); // // Put a character to show start of example. This will display on the // terminal. // UARTCharPut(UART0_BASE, '!'); // // Enter a loop to read characters from the UART, and write them back // (echo). When a line end is received, the loop terminates. // do { // // Read a character using the blocking read function. This function // will not return until a character is available. // cThisChar = UARTCharGet(UART0_BASE); // // Write the same character using the blocking write function. This // function will not return until there was space in the FIFO and // the character is written. // UARTCharPut(UART0_BASE, cThisChar); // // Stay in the loop until either a CR or LF is received. // } while((cThisChar != '\n') && (cThisChar != '\r')); // // Put a character to show the end of the example. This will display on // the terminal. // UARTCharPut(UART0_BASE, '@'); // // Return no errors // return(0); }