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TM4C123 串口回环发送小例



通过串口中断接收数据,再把接收到的数据通过串口发送出去。

//*****************************************************************************
//
// uart_echo.c - Example for reading data from and writing data to the UART in
//               an interrupt driven fashion.
//
// Copyright (c) 2012-2014 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 2.1.0.12573 of the EK-TM4C123GXL Firmware Package.
//
//*****************************************************************************

#include <stdint.h>
#include <stdbool.h>
#include "inc/hw_ints.h"
#include "inc/hw_memmap.h"
#include "driverlib/debug.h"
#include "driverlib/fpu.h"
#include "driverlib/gpio.h"
#include "driverlib/interrupt.h"
#include "driverlib/pin_map.h"
#include "driverlib/rom.h"
#include "driverlib/sysctl.h"
#include "driverlib/uart.h"

//*****************************************************************************
//
//! \addtogroup example_list
//! <h1>UART Echo (uart_echo)</h1>
//!
//! This example application utilizes the UART to echo text.  The first UART
//! (connected to the USB debug virtual serial port on the evaluation board)
//! will be configured in 115,200 baud, 8-n-1 mode.  All characters received on
//! the UART are transmitted back to the UART.
//
//*****************************************************************************

//*****************************************************************************
//
// The error routine that is called if the driver library encounters an error.
//
//*****************************************************************************
#ifdef DEBUG
void
__error__(char *pcFilename, uint32_t ui32Line)
{
}
#endif

//*****************************************************************************
//
// The UART interrupt handler.
//
//*****************************************************************************
void
UARTIntHandler(void)
{
    uint32_t ui32Status;

    //
    // Get the interrrupt status.
    //
    ui32Status = ROM_UARTIntStatus(UART0_BASE, true);

    //
    // Clear the asserted interrupts.
    //
    ROM_UARTIntClear(UART0_BASE, ui32Status);

    //
    // Loop while there are characters in the receive FIFO.
    //
    while(ROM_UARTCharsAvail(UART0_BASE))
    {
        //
        // Read the next character from the UART and write it back to the UART.
        //
        ROM_UARTCharPutNonBlocking(UART0_BASE,
                                   ROM_UARTCharGetNonBlocking(UART0_BASE));

        //
        // Blink the LED to show a character transfer is occuring.
        //
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, GPIO_PIN_2);

        //
        // Delay for 1 millisecond.  Each SysCtlDelay is about 3 clocks.
        //
        SysCtlDelay(SysCtlClockGet() / (1000 * 3));

        //
        // Turn off the LED
        //
        GPIOPinWrite(GPIO_PORTF_BASE, GPIO_PIN_2, 0);

    }
}

//*****************************************************************************
//
// Send a string to the UART.
//
//*****************************************************************************
void
UARTSend(const uint8_t *pui8Buffer, uint32_t ui32Count)
{
    //
    // Loop while there are more characters to send.
    //
    while(ui32Count--)
    {
        //
        // Write the next character to the UART.
        //
        ROM_UARTCharPutNonBlocking(UART0_BASE, *pui8Buffer++);
    }
}

//*****************************************************************************
//
// This example demonstrates how to send a string of data to the UART.
//
//*****************************************************************************
int
main(void)
{
    //
    // Enable lazy stacking for interrupt handlers.  This allows floating-point
    // instructions to be used within interrupt handlers, but at the expense of
    // extra stack usage.
    //
    ROM_FPUEnable();
    ROM_FPULazyStackingEnable();

    //
    // Set the clocking to run directly from the crystal.
    //
    ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN |
                       SYSCTL_XTAL_16MHZ);

    //
    // Enable the GPIO port that is used for the on-board LED.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);

    //
    // Enable the GPIO pins for the LED (PF2).
    //
    ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2);

    //
    // Enable the peripherals used by this example.
    //
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Enable processor interrupts.
    //
    ROM_IntMasterEnable();

    //
    // Set GPIO A0 and A1 as UART pins.
    //
    GPIOPinConfigure(GPIO_PA0_U0RX);
    GPIOPinConfigure(GPIO_PA1_U0TX);
    ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Configure the UART for 115,200, 8-N-1 operation.
    //
    ROM_UARTConfigSetExpClk(UART0_BASE, ROM_SysCtlClockGet(), 115200,
                            (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
                             UART_CONFIG_PAR_NONE));

    //
    // Enable the UART interrupt.
    //
    ROM_IntEnable(INT_UART0);
    ROM_UARTIntEnable(UART0_BASE, UART_INT_RX | UART_INT_RT);

    //
    // Prompt for text to be entered.
    //
    UARTSend((uint8_t *)"\033[2JEnter text: ", 16);

    //
    // Loop forever echoing data through the UART.
    //
    while(1)
    {
    }
}
  • 启动文件中添加中断服务函数

    //*****************************************************************************
    //
    // startup_ccs.c - Startup code for use with TI's Code Composer Studio.
    //
    // Copyright (c) 2012-2014 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 2.1.0.12573 of the EK-TM4C123GXL Firmware Package.
    //
    //*****************************************************************************
    
    #include <stdint.h>
    #include "inc/hw_nvic.h"
    #include "inc/hw_types.h"
    
    //*****************************************************************************
    //
    // Forward declaration of the default fault handlers.
    //
    //*****************************************************************************
    void ResetISR(void);
    static void NmiSR(void);
    static void FaultISR(void);
    static void IntDefaultHandler(void);
    
    //*****************************************************************************
    //
    // External declaration for the reset handler that is to be called when the
    // processor is started
    //
    //*****************************************************************************
    extern void _c_int00(void);
    
    //*****************************************************************************
    //
    // Linker variable that marks the top of the stack.
    //
    //*****************************************************************************
    extern uint32_t __STACK_TOP;
    
    //*****************************************************************************
    //
    // External declaration for the interrupt handler used by the application.
    //
    //*****************************************************************************
    extern void UARTIntHandler(void);
    
    //*****************************************************************************
    //
    // The vector table.  Note that the proper constructs must be placed on this to
    // ensure that it ends up at physical address 0x0000.0000 or at the start of
    // the program if located at a start address other than 0.
    //
    //*****************************************************************************
    #pragma DATA_SECTION(g_pfnVectors, ".intvecs")
    void (* const g_pfnVectors[])(void) =
    {
        (void (*)(void))((uint32_t)&__STACK_TOP),
                                                // The initial stack pointer
        ResetISR,                               // The reset handler
        NmiSR,                                  // The NMI handler
        FaultISR,                               // The hard fault handler
        IntDefaultHandler,                      // The MPU fault handler
        IntDefaultHandler,                      // The bus fault handler
        IntDefaultHandler,                      // The usage fault handler
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // SVCall handler
        IntDefaultHandler,                      // Debug monitor handler
        0,                                      // Reserved
        IntDefaultHandler,                      // The PendSV handler
        IntDefaultHandler,                      // The SysTick handler
        IntDefaultHandler,                      // GPIO Port A
        IntDefaultHandler,                      // GPIO Port B
        IntDefaultHandler,                      // GPIO Port C
        IntDefaultHandler,                      // GPIO Port D
        IntDefaultHandler,                      // GPIO Port E
        UARTIntHandler,                         // UART0 Rx and Tx
        IntDefaultHandler,                      // UART1 Rx and Tx
        IntDefaultHandler,                      // SSI0 Rx and Tx
        IntDefaultHandler,                      // I2C0 Master and Slave
        IntDefaultHandler,                      // PWM Fault
        IntDefaultHandler,                      // PWM Generator 0
        IntDefaultHandler,                      // PWM Generator 1
        IntDefaultHandler,                      // PWM Generator 2
        IntDefaultHandler,                      // Quadrature Encoder 0
        IntDefaultHandler,                      // ADC Sequence 0
        IntDefaultHandler,                      // ADC Sequence 1
        IntDefaultHandler,                      // ADC Sequence 2
        IntDefaultHandler,                      // ADC Sequence 3
        IntDefaultHandler,                      // Watchdog timer
        IntDefaultHandler,                      // Timer 0 subtimer A
        IntDefaultHandler,                      // Timer 0 subtimer B
        IntDefaultHandler,                      // Timer 1 subtimer A
        IntDefaultHandler,                      // Timer 1 subtimer B
        IntDefaultHandler,                      // Timer 2 subtimer A
        IntDefaultHandler,                      // Timer 2 subtimer B
        IntDefaultHandler,                      // Analog Comparator 0
        IntDefaultHandler,                      // Analog Comparator 1
        IntDefaultHandler,                      // Analog Comparator 2
        IntDefaultHandler,                      // System Control (PLL, OSC, BO)
        IntDefaultHandler,                      // FLASH Control
        IntDefaultHandler,                      // GPIO Port F
        IntDefaultHandler,                      // GPIO Port G
        IntDefaultHandler,                      // GPIO Port H
        IntDefaultHandler,                      // UART2 Rx and Tx
        IntDefaultHandler,                      // SSI1 Rx and Tx
        IntDefaultHandler,                      // Timer 3 subtimer A
        IntDefaultHandler,                      // Timer 3 subtimer B
        IntDefaultHandler,                      // I2C1 Master and Slave
        IntDefaultHandler,                      // Quadrature Encoder 1
        IntDefaultHandler,                      // CAN0
        IntDefaultHandler,                      // CAN1
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // Hibernate
        IntDefaultHandler,                      // USB0
        IntDefaultHandler,                      // PWM Generator 3
        IntDefaultHandler,                      // uDMA Software Transfer
        IntDefaultHandler,                      // uDMA Error
        IntDefaultHandler,                      // ADC1 Sequence 0
        IntDefaultHandler,                      // ADC1 Sequence 1
        IntDefaultHandler,                      // ADC1 Sequence 2
        IntDefaultHandler,                      // ADC1 Sequence 3
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // GPIO Port J
        IntDefaultHandler,                      // GPIO Port K
        IntDefaultHandler,                      // GPIO Port L
        IntDefaultHandler,                      // SSI2 Rx and Tx
        IntDefaultHandler,                      // SSI3 Rx and Tx
        IntDefaultHandler,                      // UART3 Rx and Tx
        IntDefaultHandler,                      // UART4 Rx and Tx
        IntDefaultHandler,                      // UART5 Rx and Tx
        IntDefaultHandler,                      // UART6 Rx and Tx
        IntDefaultHandler,                      // UART7 Rx and Tx
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // I2C2 Master and Slave
        IntDefaultHandler,                      // I2C3 Master and Slave
        IntDefaultHandler,                      // Timer 4 subtimer A
        IntDefaultHandler,                      // Timer 4 subtimer B
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // Timer 5 subtimer A
        IntDefaultHandler,                      // Timer 5 subtimer B
        IntDefaultHandler,                      // Wide Timer 0 subtimer A
        IntDefaultHandler,                      // Wide Timer 0 subtimer B
        IntDefaultHandler,                      // Wide Timer 1 subtimer A
        IntDefaultHandler,                      // Wide Timer 1 subtimer B
        IntDefaultHandler,                      // Wide Timer 2 subtimer A
        IntDefaultHandler,                      // Wide Timer 2 subtimer B
        IntDefaultHandler,                      // Wide Timer 3 subtimer A
        IntDefaultHandler,                      // Wide Timer 3 subtimer B
        IntDefaultHandler,                      // Wide Timer 4 subtimer A
        IntDefaultHandler,                      // Wide Timer 4 subtimer B
        IntDefaultHandler,                      // Wide Timer 5 subtimer A
        IntDefaultHandler,                      // Wide Timer 5 subtimer B
        IntDefaultHandler,                      // FPU
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // I2C4 Master and Slave
        IntDefaultHandler,                      // I2C5 Master and Slave
        IntDefaultHandler,                      // GPIO Port M
        IntDefaultHandler,                      // GPIO Port N
        IntDefaultHandler,                      // Quadrature Encoder 2
        0,                                      // Reserved
        0,                                      // Reserved
        IntDefaultHandler,                      // GPIO Port P (Summary or P0)
        IntDefaultHandler,                      // GPIO Port P1
        IntDefaultHandler,                      // GPIO Port P2
        IntDefaultHandler,                      // GPIO Port P3
        IntDefaultHandler,                      // GPIO Port P4
        IntDefaultHandler,                      // GPIO Port P5
        IntDefaultHandler,                      // GPIO Port P6
        IntDefaultHandler,                      // GPIO Port P7
        IntDefaultHandler,                      // GPIO Port Q (Summary or Q0)
        IntDefaultHandler,                      // GPIO Port Q1
        IntDefaultHandler,                      // GPIO Port Q2
        IntDefaultHandler,                      // GPIO Port Q3
        IntDefaultHandler,                      // GPIO Port Q4
        IntDefaultHandler,                      // GPIO Port Q5
        IntDefaultHandler,                      // GPIO Port Q6
        IntDefaultHandler,                      // GPIO Port Q7
        IntDefaultHandler,                      // GPIO Port R
        IntDefaultHandler,                      // GPIO Port S
        IntDefaultHandler,                      // PWM 1 Generator 0
        IntDefaultHandler,                      // PWM 1 Generator 1
        IntDefaultHandler,                      // PWM 1 Generator 2
        IntDefaultHandler,                      // PWM 1 Generator 3
        IntDefaultHandler                       // PWM 1 Fault
    };
    
    //*****************************************************************************
    //
    // This is the code that gets called when the processor first starts execution
    // following a reset event.  Only the absolutely necessary set is performed,
    // after which the application supplied entry() routine is called.  Any fancy
    // actions (such as making decisions based on the reset cause register, and
    // resetting the bits in that register) are left solely in the hands of the
    // application.
    //
    //*****************************************************************************
    void
    ResetISR(void)
    {
        //
        // Jump to the CCS C initialization routine.  This will enable the
        // floating-point unit as well, so that does not need to be done here.
        //
        __asm("    .global _c_int00\n"
              "    b.w     _c_int00");
    }
    
    //*****************************************************************************
    //
    // This is the code that gets called when the processor receives a NMI.  This
    // simply enters an infinite loop, preserving the system state for examination
    // by a debugger.
    //
    //*****************************************************************************
    static void
    NmiSR(void)
    {
        //
        // Enter an infinite loop.
        //
        while(1)
        {
        }
    }
    
    //*****************************************************************************
    //
    // This is the code that gets called when the processor receives a fault
    // interrupt.  This simply enters an infinite loop, preserving the system state
    // for examination by a debugger.
    //
    //*****************************************************************************
    static void
    FaultISR(void)
    {
        //
        // Enter an infinite loop.
        //
        while(1)
        {
        }
    }
    
    //*****************************************************************************
    //
    // This is the code that gets called when the processor receives an unexpected
    // interrupt.  This simply enters an infinite loop, preserving the system state
    // for examination by a debugger.
    //
    //*****************************************************************************
    static void
    IntDefaultHandler(void)
    {
        //
        // Go into an infinite loop.
        //
        while(1)
        {
        }
    }